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Early studies of genetic variation in moose (Alces alces) indicated little variation. Recent studies have indicated higher levels of variation in nuclear markers; nonetheless, genetic heterogeneity of moose is relatively low compared with other mammals. Similarly, variation in mitochondrial DNA of moose is limited worldwide, indicating low historic effective population size and a common ancestry for moose within the last 60,000 years. That ancestor most likely lived in central Asia. Moose likely exhibit low levels of heterogeneity because of population bottlenecks in the late Pleistocene caused by latitudinal shifts in habitat from recurrent climate reversals. A northward movement of boreal forest associated with the end of the last ice age facilitated the northward advance of Asian populations and colonization of the New World, which occurred as a single entry by relatively few moose immediately prior to the last flooding of the Bering land bridge. Despite suffering serial population bottlenecks historically, moose have exhibited a notable ability to adapt to a changing environment, indicating that limited neutral genetic variation may not indicate limited adaptive genetic variation. We conclude that morphological variation among moose worldwide occurred within a few thousand years and indicates that moose underwent episodes of rapid and occasionally convergent evolution. Genetic change in moose populations over very short time scales (tens or hundreds of years) is possible under harvest management regimes and those changes may not be beneficial to moose in the long term. Modeling exercises have demonstrated that harvest strategies can have negative consequences on neutral genetic variation as well as alleles underpinning fitness traits. Biologists should consider such outcomes when evaluating management options.
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Kris J. Hundertmark1 and R. Terry Bowyer2
1Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks,
Fairbanks, AK 99775, USA; 2Department of Biological Sciences, Idaho State University, Pocatello,
ID 83209, USA
ABSTRACT: Early studies of genetic variation in moose (Alces alces) indicated little variation.
Recent studies have indicated higher levels of variation in nuclear markers; nonetheless, genetic
heterogeneity of moose is relatively low compared with other mammals. Similarly, variation in
mitochondrial DNA of moose is limited worldwide, indicating low historic effective population size
and a common ancestry for moose within the last 60,000 years. That ancestor most likely lived in
central Asia. Moose likely exhibit low levels of heterogeneity because of population bottlenecks
in the late Pleistocene caused by latitudinal shifts in habitat from recurrent climate reversals. A
northward movement of boreal forest associated with the end of the last ice age facilitated the
northward advance of Asian populations and colonization of the New World, which occurred as
a single entry by relatively few moose immediately prior to the last flooding of the Bering land bridge.
Despite suffering serial population bottlenecks historically, moose have exhibited a notable ability
to adapt to a changing environment, indicating that limited neutral genetic variation may not indicate
limited adaptive genetic variation. We conclude that morphological variation among moose
worldwide occurred within a few thousand years and indicates that moose underwent episodes of
rapid and occasionally convergent evolution. Genetic change in moose populations over very short
time scales (tens or hundreds of years) is possible under harvest management regimes and those
changes may not be beneficial to moose in the long term. Modeling exercises have demonstrated
that harvest strategies can have negative consequences on neutral genetic variation as well as
alleles underpinning fitness traits. Biologists should consider such outcomes when evaluating
management options.
ALCES VOL. 40: 103-122 (2004)
Key words: adaptation, Alces, convergent evolution, moose, mtDNA, phylogeography, Pleistocene,
range expansion
Genetics have long had a central role in
biological investigations, and provide ana-
lytical tools that are applicable across a
broad spectrum of investigation. For in-
stance, genetic analysis can provide insights
into such diverse investigations as evolu-
tionary histories of species (Avise et al.
1987, 2000), interactions and relationships
among populations (Blundell et al. 2002) or
individuals (Quellar et al. 1993), evaluation
of the success of specific management ac-
tions (Vernesi et al. 2002), population and
behavioral ecology (Scribner and Chesser
2001), and food habits (Symondson 2002).
Recent advances in collection and analysis
of genetic data have facilitated more re-
fined approaches to evolutionary and popu-
lation genetic questions, and our under-
standing of moose biology has benefited as
a result of those advances.
Evolution and taxonomy of moose (Alces
alces) have been reviewed previously
(Peterson 1955; Groves and Grubb 1987;
Geist, 1987a,b, 1998; Sher 1987; Lister 1993;
Guthrie 1995; Bubenik 1998; Bowyer et al.
2003) and have encompassed aspects of
behavior, morphology, paleontology, and
genetics, but no review has dealt specifi-
cally with genetics. In this review, our goal
is to provide an overview of older studies
while focusing on recent advances in genet-
ics and phylogeography (see definition in
Appendix 1) of moose and the insights they
The broad scope of genetic and evolu-
tionary investigations in species biology
would make a complete review of all studies
disjointed. Yet, approximately half of all
published studies of moose genetics have
been published since the comprehensive
treatise “Ecology and Management of the
North American Moose” (Franzmann and
Schwartz 1998) was compiled; thus, we
were compelled to present the most com-
plete review possible. In an effort to present
a cogent summary of all relevant studies,
we have divided this review into 3 parts: (1)
assessing genetic diversity, where we re-
view the different types of markers exam-
ined in studies of moose genetics and the
conclusions drawn from those studies; (2)
moose evolution and phylogeography, where
we examine the evolutionary descent of
moose and processes that have shaped the
genetic variation and structure observed
today; and (3) genetic effects of harvest,
which reviews a small but important body of
work composed of management-based
modeling that examined effects of various
harvest regimes on population and genetic
One potential difficulty in discussing
genetic analyses is the use of specialized
terminology. To avoid uncertainty and en-
hance understanding, we provide a brief
glossary of terms used in this review (Ap-
pendix 1). Terms defined in the glossary
are highlighted in bold in the text at their first
The Allozyme Era
First reports of genetic investigations of
moose were published by Braend (1962,
cited by Gyllensten et al. 1980), Nadler et
al. (1967), and Shubin (1969, cited by
Gyllensten et al. 1980), wherein those au-
thors examined electrophoretic variation in
proteins from blood serum; no variation in
those genetic markers occurred in Scandi-
navia, North America, and central Russia,
respectively. The first study to report ge-
netic variability was Ryman et al. (1977),
who examined 1,384 moose from 3 areas of
Sweden for polymorphism at 23 allozyme
loci. That study reported only 1 locus to be
polymorphic, however, and only in 1 region.
Although they suspected that allele fre-
quencies varied geographically within the 1
variable region, the difference was not sta-
tistically significant. Those authors con-
cluded that genetic drift associated with a
severe population bottleneck (reduction in
population size) in Sweden in the 19th cen-
tury was a probable cause of the observed
lack of diversity. Wilhelmson et al. (1978),
examining variation in serum proteins, noted
no differences between Canadian and Eu-
ropean moose. From that evidence, they
concluded that moose populations on sepa-
rate continents had not undergone signifi-
cant genetic drift despite being separated
for thousands of years, implying that effec-
tive population sizes of moose populations
historically had been large.
Wilhelmson et al. (1978) also proposed
that historic population bottlenecks in Swe-
den had not been severe enough to have had
an effect on genetic diversity of moose.
Gyllensten et al. (1980) conducted exten-
sive screening of a transferrin locus from
moose across Fennoscandia and detected a
single polymorphism occurring in Norway,
Sweden, and Finland. Nonetheless, the poly-
morphism was present in only 6 of 16
populations and the uncommon allele never
exceeded 6% in any population. The au-
thors presented differences in frequency of
the uncommon allele as evidence of differ-
entiation of populations geographically, sup-
porting observations of Ryman et al. (1977).
Reliance on the occurrence of a single rare
polymorphism to demonstrate population
subdivision, however, is tenuous at best.
Those early studies and others created
an impression among some biologists that
certain species, including moose, possessed
little genetic variation across the genome.
Hypotheses explaining this in evolutionary
terms were proposed. Selander and
Kaufman (1973) proposed the environmen-
tal-grain hypothesis, which stated that large,
highly mobile animals exhibited less genetic
variability than small, sedentary species.
That hypothesis further stated that highly
mobile mammals would exhibit greater ho-
mogeneity across large areas than more
sedentary forms. Other hypotheses pro-
posed that r-strategists were less variable
than K-strategists (Harrington 1985), ge-
netic heterogeneity was greater in species
inhabiting broad arrays of habitats com-
pared with habitat specialists (Nevo 1978),
or that northern cervids inhabiting boreal
forests were less variable than their rela-
tives to the south (Smith et al. 1990).
Analyses of 23 allozyme loci in > 700
individuals representing 18 moose
populations in Scandinavia were required to
reveal extensive genetic variation in moose
(Ryman et al. 1980). Those authors refuted
the environmental-grain hypothesis, con-
cluding that large mammals in general, and
large cervids in particular, are not naturally
monomorphic; previous studies of moose
had examined too few loci or individuals to
detect variation. Nonetheless, those au-
thors noted that genetic variability in moose
was somewhat less than that observed in
many other species of mammals (Nevo
1978), but that genetic drift due to small
historic population size was a more likely
explanation than any specific evolutionary
strategy. Thus, genetic drift was once again
proposed as being an important factor in
determining the structure of genetic diver-
sity. In another comprehensive study,
Chesser et al. (1982) examined 1,169 indi-
viduals from 4 regions in Sweden for a
single polymorphic locus and reported vari-
ation in allele frequencies among those re-
gions and, perhaps more importantly, sig-
nificant variation within 1 of those regions.
Detecting variation at geographic scales
small enough to be considered within a
single population illustrated that structure of
moose populations existed at scales smaller
than previously imagined, and that vagility
was not inconsistent with genetic structur-
ing.The most recent study of allozyme vari-
ation in moose reported extensive variation
in a moose population in Alaska
(Hundertmark et al. 1992). The level of
genetic diversity observed was greater than
that reported elsewhere in moose and was
similar to levels observed in white-tailed
deer, a species known for extensive allozyme
diversity (Smith et al. 1984). Hundertmark
et al. (1992) hypothesized that lesser levels
of variability described in moose from Scan-
dinavia and other regions of North America
were attributable to glacial history. All
other moose populations studied to that point
occurred in previously glaciated terrain that
was colonized by moose after retreat of
Pleistocene ice sheets. Colonization of
previously glaciated areas could have re-
sulted in serial founder events that reduced
genetic diversity (Sage and Wolff 1986).
Hundertmark et al. (1992) argued that
Alaska could have served as a refugium for
moose in which genetic diversity could have
been maintained because of a large effec-
tive population size.
Assessing Variation at the Sequence
The first investigation of highly poly-
morphic molecular markers in moose docu-
mented 4 alleles in a microsatellite-like
locus in 17 individuals from Sweden (Ellegren
et al. 1991). Eight genotypes were re-
ported, which represented a heretofore un-
thinkable level of polymorphism. Those
authors investigated the inheritance of that
locus in a 2-generation pedigree and deter-
mined that the alleles exhibited Mendelian
inheritance. That study and others like it
laid the foundation for the explosion of
interest in population genetics and
phylogenetics based on molecular markers
and the polymerase chain reaction (PCR;
Mullis et al. 1986).
The advent of PCR represented one of
the truly significant advances in the history
of molecular biology and genetics. The
process allows in-vitro amplification of DNA
from miniscule amounts of starting material
(theoretically as little as 1 molecule of DNA)
to provide sufficient quantities for analysis.
No longer were researchers required to
sacrifice animals to acquire sufficient quan-
tities and types of tissues for genetic analy-
ses because any nucleated cell held the
complete genetic complement of the indi-
vidual. PCR offered unsurpassed access to
the genome, and researchers soon applied
that to study genetics of moose.
Mikko and Andersson (1995) conducted
the first analysis of functional loci in an
analysis of variation in the major histocom-
patibility complex (MHC) in moose from
Sweden and Canada. The MHC is a family
of genes important in immune system func-
tion, and low levels of diversity of MHC
alleles have been interpreted as indicators
of lost evolutionary potential and increased
susceptibility to pathogens (Hedrick 1994).
Mikko and Andersson (1995) noted very
low levels of MHC variation in both Swed-
ish and Canadian moose. Moreover, those
authors documented similarity among alleles
between continents and inferred the exist-
ence of a bottleneck in an ancient moose
lineage prior to divergence of European and
Canadian lineages. Mikko and Andersson
(1995) applied a molecular clock to DNA
sequence variation in the control region
of mitochondrial DNA (mtDNA) to date
the time of divergence of Swedish and
Canadian moose, which they estimated at
165,000-350,000 years ago.
The time since divergence of European
moose also was analyzed by Ellegren et al.
(1996). They assessed variation in
minisatellite loci of Swedish moose and
concluded that normal evolutionary proc-
esses could have generated the amount of
variation observed within 10,000-50,000
years after a severe bottleneck. Their
implication, therefore, was that the estimate
of divergence provided by Mikko and
Andersson (1995) was too old by perhaps 1
order of magnitude. Surprisingly, the two
data sets are not inconsistent; indeed, they
show similar levels of variation considering
differences in evolutionary rates among
marker types. The differences in estimates
for date of divergence relate more to the
evolutionary rate estimates used than to
differences in genetic variability.
Microsatellite loci were first described
for moose by Wilson et al. (1997) and Røed
and Midthjell (1998). Broders et al. (1999)
demonstrated the utility of microsatellites
for assessing population structure in moose
by assessing consequences of founder
events in Canada. Heterozygosity in 3
populations founded by few individuals de-
creased from 14-30% compared with the
source population. Broders et al. (1999), in
assessing variability of moose on the island
of Newfoundland, Canada, demonstrated
that 2 consecutive founder events reduced
heterozygosity by 46%. Although they could
not discern any decrease in fitness as a
result of the decrease in diversity, the au-
thors questioned the long-term viability of
those moose populations. Nonetheless, lev-
els of diversity in neutral microsatellite loci
were not indicative of diversity in functional
loci in moose (Wilson et al. 2003).
The Future
Microsatellites have replaced allozymes
as the most widely used molecular marker
for assessing nuclear genetic diversity, and
will be the choice of geneticists for the
foreseeable future (Bruford et al. 1996).
There are problems, however, with analysis
of microsatellites because the ways in which
they mutate into new forms are not entirely
understood (Hancock 1999). In the future,
a new type of analysis called single nucle-
otide polymorphism (SNP, pronounced
“snip”) may replace microsatellites for some
applications (Fries and Durstewitz 2001,
Brumfield et al. 2003). This new technol-
ogy allows a single nucleotide site to be
queried for presence of a particular nucle-
otide and presence or absence can be con-
verted to a binary code. Current technology
(so-called “real-time PCR” and “DNA
chips”) allows for fast and accurate exami-
nation of many individuals and SNPs, but
we must await the development and char-
acterization of marker loci before broad
application of this new family of molecular
markers can be considered.
Origins of Modern Moose
Moose (Alces alces) are a young spe-
cies in the evolutionary scheme of large
mammals. The genus Alces first appears in
the fossil record 2 million years ago
(Thouveny and Bonifay 1984) and fossils
attributable to A. alces are first recorded
approximately 100,000 years ago (Lister
1993). Those dates are very recent consid-
ering that the subfamily Odocoileinae, to
which moose belong, diverged from other
deer lineages 9-12 million years ago
(Miyamoto et al. 1990).
Paleontological evidence indicated Eu-
rope as the place of origin of the genus
Alces (Lister 1993). The genus never was
diverse, with only one species present in the
fossil record at any particular time. Yet, the
species assumed to be the precursor to A.
alces, the broad-fronted moose (A.
latifrons) was distributed across Eurasia
and into northwestern North America for a
time before becoming extinct in Beringia at
the end of the Pleistocene (Guthrie 1995).
Thus, the widespread distribution of modern
moose and its immediate ancestor indicate
a degree of evolutionary success despite a
paucity of species diversity.
Up to 8 subspecies of moose are recog-
nized worldwide (Fig. 1); 4 in Eurasia and 4
in North America (Peterson 1955). That
number is open to question, however. Geist
(1987a, 1998) contends that there are 2
predominant types of moose in the world:
American and European, following the con-
vention of Flerov (1952). To the former
type he assigns all North American moose
as well as eastern Asian subspecies A. a.
burturlini and A. a. pfizenmayeri. He
based his opinion primarily on morphology
and noted similar geographic divisions in
taxonomy among reindeer and caribou
(Rangifer tarandus) and red deer and North
American elk (Cervus elaphus; Geist 1998).
He further contended that those morpho-
logical types should correspond to subspe-
cies designations. Therefore, Geist (1998)
recognized A. a. alces of Europe and A. a.
americana in eastern Asia and North
America. He also suggested that A. a.
americanus has precedence under
nomenclatural conventions as the proper
name for the east Asian-North American
subspecies. He referred to A. a.
cameloides in northern China, Mongolia,
and southeastern Russia as part of a primi-
tive fauna native to that region and recog-
nized that subspecies as a valid taxon al-
though he also refers to it as an American-
type moose (Geist 1998:230).
The 2-types hypothesis is supported to
some degree by karyotype (Boeskorov 1996,
1997) and some data on mtDNA (Mikko
Fig. 1. Approximate ranges of 8 subspecies of moose worldwide. A. a. a. = A. a. alces, A. a. p. = A.
a. pfizenmayeri, A. a. c. = A. a. cameloides, A. a. b. = A. a. burturlini, A. a. g. = A. a. gigas, A. a.
an. = A. a. andersoni, A. a. s. = A. a. shirasi, A. a. am. = A. a. americana, * = introduced population
in Newfoundland.
and Andersson 1995). Most Eurasian moose
have a karyotype of 2N = 68, whereas
North American moose have 2N = 70. That
difference derives from a Robertsonian
translocation of 2 acrocentric chromosomes
into a single metacentric chromosome or
vice versa. Although that chromosomal
polymorphism originally was thought to sepa-
rate Eurasian and North American moose
(Groves and Grubb 1987), the 2N = 70 form
was recently discovered in eastern Asia
(Boeskorov 1996, 1997). Similarly, a length
mutation (insertion-deletion, or indel) within
the control region of mtDNA originally was
described as discriminating between North
American and European moose (Mikko and
Andersson 1995), but subsequent investiga-
tions documented that indel in moose from
Eastern Asia (Hundertmark et al. 2002b,
Udina et al. 2002). Although the precise
geographic distributions of those
polymorphisms in karyotype and mtDNA
length are not well described, they seem to
correspond geographically with a zone of
intergradation in east-central Asia, similar
to that proposed for American and Eurasian
types of moose (Flerov 1952, Geist 1998).
More work is needed to determine the ex-
tent of that geographic correspondence and
to determine if it coincides with subspecies
boundaries. Moreover, the question of re-
productive viability of the two chromosomal
races must be addressed. Indeed, Boeskorov
(1997) has proposed that the chromosomal
races are different species and Groves and
Grubb (1987) have identified them as “semi-
species.” We caution, however, that chro-
mosome numbers may be a poor designator
of species among large mammals (Bowyer
et al. 2000).
Hundertmark et al. (2002b) tested the
2-types hypothesis by examining the distri-
bution of genetic variance of mtDNA among
and within different hypothetical population
structures. Those authors sampled moose
throughout their worldwide distribution and
arranged them into either 2 groups (corre-
sponding to the 2-types hypothesis) or 3
groups corresponding to continent of origin
(Asia, Europe, and North America). They
then examined the distribution of genetic
variance within and among or between
groups, predicting that the correct structure
would minimize within-group variation and
maximize among-group variation. Percent-
age of total variation observed among the 3
groups was slightly greater than variation
between the 2 groups (61.5% vs. 58.1%),
and variation among populations within
groups was minimized in the 3-group com-
parison (21.6% vs. 28.8% in the 2-group
comparison). Therefore, Hundertmark et
al. (2002b) concluded that mtDNA data
provided no support for a 2-type over a 3-
type hypothesis. That finding can be visu-
alized by a phylogenetic tree constructed
from haplotypes originally reported by
Hundertmark et al. (2002b, 2003), which
shows North American moose as distinct
from both Asian and European forms
(Fig. 2).
Ancient Bottlenecks and the Mother of
All Moose
Moose worldwide exhibit little varia-
tion in a fragment of the mitochondrial cyto-
chrome-b gene (Hundertmark et al. 2002a).
Cytochrome b is useful for constructing
mammalian phylogenies (Irwin et al. 1991)
and a paucity of variation in moose indi-
cated a recent common ancestry likely due
to a severe bottleneck that affected all
extant lineages (Hundertmark et al. 2002a),
which is in agreement with the findings of
Mikko and Andersson (1995). Analysis of
variation within the mitochondrial control
region, which evolves at a much faster rate
than cytochrome b (Lopez et al. 1997), was
Fig. 2. Unrooted phylogenetic tree of moose
populations and subspecies worldwide, with
the exception of A. a. pfizenmayeri, using FST
as the distance measure [data from
Hundertmark et al. (2002b, 2003)]. Note the
distinct positions of the 3 Eurasian subspe-
cies and North American moose, which do not
support an hypothesis of 2 or 3 races of moose
Fig. 3. A phylogenetic tree of haplotypes of the
mitochondrial control region of moose. Sym-
bols indicate region of origin, with black sym-
bols indicating Asian origin. Distinct clades
or phylogroups are indicated on the right.
From Hundertmark et al. (2002b).
necessary to reveal significant levels of
variation in moose and subsequently geo-
graphic patterns were revealed.
Control region haplotypes of moose
can be divided into 3 clades, or haplogroups
(Fig. 3). The basal haplogroup (i.e., the
group that diverges first from the base of
the tree) is entirely Asian, which suggests
that those are the oldest moose haplotypes.
The two other haplogroups are primarily
European and primarily North American,
although some Asian haplotypes occur in
both. The distribution of haplogroups on a
worldwide scale illustrates the age of con-
tinental assemblages of haplotypes (Fig. 4).
The Yakutia area contains moose from all 3
haplogroups. The Russian Far East con-
tains both European and Asian haplogroups,
but not North American, and both Europe
and North America contain only 1
haplogroup each. Therefore, Yakutia can
be identified as the area from which all
extant moose lineages were derived, i.e., it
is the oldest extant moose population that
has been sampled.
Yakutia probably was the center of a
single moose population during the last ice
age, or at least was the location of the only
population to provide descendants of mod-
ern moose. Moose would have been re-
stricted in their distribution because the
cooler climate in Asia at that time would
have resulted in a shift of boreal forest
habitat to the south. That habitat could have
shifted only so far southward, because of
prominent mountains running east-west,
which would have formed an effective bar-
rier to further movement to the south (Hewitt
During the last ice age, there were 2
periods of maximum glacial advance, termed
the lower and upper pleniglacials. Those
episodes occurred at approximately 62,000
and 20,000 years ago, respectively (Fulton
et al. 1986). Boreal forest habitats in Asia
would have shifted to the south during those
cooling episodes and would have been com-
pressed against the northern slopes of moun-
Fig. 4. Distribution of mitochondrial haplogroups
worldwide. Note that moose from the Yakutia
area have the most diverse composition and
that moose from North America do not share
haplogroups with moose from Russian Far
59,000 and 14,000 years ago. When expan-
sion times of moose are overlaid on a profile
of global temperature change for the last ice
age (Jouzel et al. 1987), population expan-
sion is correlated with warming trends fol-
lowing the pleniglacials (Fig. 6). Conse-
quently, the evolution and geographic distri-
bution of moose seems to have been af-
fected substantially by climate change, par-
ticularly climate reversals associated with
the late Pleistocene and early Holocene.
Coming to America
Cronin (1992) analyzed subspecific vari-
ation in North American cervids using re-
striction fragment length polymorphisms
(RFLP) of mtDNA. Despite analyzing 32
moose sampled from different regions of
North America, he documented no varia-
tion among haplotypes from that continent.
In comparison to other North American
cervids, the lack of variation among subspe-
cies of moose was interpreted as an indica-
Fig. 5. Glacial coverage during the last glacial
maximum, superimposed on a map of present-
day sea level. Note that the Bering land bridge
between North America and Asia would have
been exposed during the glacial maximum due
to lower sea levels. Names of major ice sheets
are provided.
tain ranges. During subsequent warming
intervals, moose habitat would have spread
to the north, allowing moose populations to
expand (Guthrie 1995). Unlike North
America, much of Eurasia was not glaci-
ated during those periods (Arkhipov et al.
1986), providing potential dispersal routes
across the continent (Fig. 5). The process
of latitudinal shifts of range associated with
episodes of climate change results in de-
creases of existing genetic diversity (Hewitt
1996) and leaves characteristic signatures
in the genome of modern moose.
Moose in Eurasia underwent 2 distinct,
recent population expansions (Hundertmark
et al. 2002b). Any other historic population
processes preceding those expansions are
not detectable because low population sizes
eliminated much of the genetic variation
present in the pre-bottleneck populations,
and hence no signature from those times
exists in the present genome. By applying a
molecular clock to those expansion data,
Hundertmark et al. (2002b) estimated that
the expansions occurred approximately
160 140 120 100 80 60 40 20 0
Thousands of years ago
Temperature di
Fig. 6. Representation of mean global tempera-
tures during the last 160,000 years relative to
mean temperature in 1900. Negative tempera-
ture differences indicate periods colder than
today. The 2 glacial maxima of the last ice age
are indicated by arrows. Estimated dates of
moose population expansion are indicated by
dashed lines and correspond to periods of
warming associated with glacial retreat and
northward advance of the boreal forest in
Eurasia. Temperature profile adapted from
ity in composition of mtDNA haplotypes.
As noted previously, North American sub-
species are distinct from European and
Asian subspecies (Fig. 2) and none of the
Asian haplotypes in the North American
haplogroup were found in the Russian Far
East. All haplotypes found in the Russian
Far East (Magadan Oblast) are restricted to
haplogroup 2 (Fig. 3), which contains all
European haplotypes. A likely colonization
scenario entails closely related moose from
central Asia colonizing both Europe and
North America.
Lack of genetic similarity between
moose in Alaska and the Russian Far East
is inconsistent with the scenario proposed
by Hundertmark et al. (2002b) concerning a
colonizing wave of moose traveling from
Asia to North America through Beringia. A
single wave of moose colonizing North
America through Beringia would have left
genetically similar populations on either side
of the Bering Strait after the Bering land
bridge flooded. Yet, ages of subfossil re-
mains of moose from North America indi-
cate clearly that A. alces was present in
Alaska prior to anywhere else on the conti-
nent (Guthrie 1990, Hundertmark et al. 2003),
unequivocally supporting an entry through
Beringia. One hypothesis that accounts for
this seeming paradox is that 1 or both of
those populations underwent population bot-
tlenecks shortly after the colonization of
North America, and have only recently
reestablished populations in those areas,
leading to the presence of different genetic
lineages in each. Moose in the Russian Far
East show evidence of an expansion ap-
proximately 1,200 years ago (Hundertmark
et al. 2002b) and continue to expand their
range toward the Bering Sea (Zheleznov
Similarly, Alaskan moose show a sur-
prising lack of mitochondrial diversity com-
pared with moose elsewhere on the conti-
nent (Hundertmark et al. 2003), which is
tion of a recent common ancestry, consist-
ent with colonization of the continent after
the retreat of ice sheets from the last ice
age (Cronin 1992). Similarly, no variation
was detected within a fragment of cyto-
chrome b in North American moose com-
pared with slight variation in Eurasia
(Hundertmark et al. 2002a).
Moose populations in North America
were established as a result of a single entry
into the continent, and that entry occurred
during the population expansion of moose
14,000 years ago at the end of the last ice
age, just before the closure of the Bering
land bridge (Guthrie 1995, Hundertmark et
al. 2002b). A recent entry into North
America is the only conclusion that is con-
sistent with limited variation in the mtDNA
control region both within North America
and between North America and Eurasia.
If moose had existed in 4 separate refugia in
North America during the last ice age, as
suggested by Peterson (1955), or had en-
tered North America from Asia more than
once, a more distant common ancestor
would be indicated. The timing of the entry
is supported not only by genetic data but
also by the distribution of suitable moose
habitat at the end of the last ice age. The
cold, dry grassland habitat that prevailed in
Beringia for most of the last ice age was
unsuitable for moose and was replaced by
boreal forest only within the last 14,000
years (Guthrie 1995).
Evidence from mtDNA variation also
indicates that North American moose did
not originate in Beringia, as some have
speculated (Cronin 1992, Geist 1998), or
recolonize the Russian Far East from North
America (Coady 1982). Moose in North
America are not closely related to moose on
the western side of the Bering Strait (Rus-
sian Far East). If those moose were once
part of the same population recently sepa-
rated by the flooding of the Bering land
bridge, we would still expect to find similar-
indicative of a bottleneck notwithstanding
the moderate levels of allozyme diversity
reported for Alaskan moose by Hundertmark
et al. (1992). Diversity of mtDNA can be
reduced to a much greater degree by a
bottleneck than diversity of nuclear DNA
because mtDNA is 4 times more sensitive
to genetic drift due to its haploid, uniparental
mode of inheritance (Birky et al. 1983).
Simultaneous bottlenecks in moose from
both sides of the Bering Strait suggest a
widespread causal factor. Recent studies
have found evidence of significant biotic
effects of climate reversals in Beringia af-
ter flooding of the Bering land bridge (Elias
2000, Mason et al. 2001, Anderson et al.
2002). Those effects offer an intriguing
mechanism for bottlenecks in Beringian
moose populations.
The greatest variation in mtDNA in
North American moose occurs within the
range of A. a. andersoni (Hundertmark et
al. 2003). Alces a. shirasi from Colorado
exhibited no diversity and A. a. gigas and A.
a. americana exhibited very little diversity.
If the paucity of mitochondrial diversity in
Alaska is due to a bottleneck and recent
expansion, those data would be consistent
with the serial-founder-events hypothesis
of North American colonization
(Hundertmark et al. 1992).
The pattern of colonization of North
America undoubtedly was influenced by
the retreating glaciers and may have had
some effect on genetic structure
(Hundertmark et al. 2003). Based on the
reconstruction of the retreat of the
Laurentide ice sheet by Dyke and Prest
(1987), we offer the following scenario of
colonization. At the last glacial maximum,
the Cordilleran and Laurentide ice sheets
created an effective barrier between east-
ern Beringia (Alaska) and other parts of the
continent (Fig. 5). As glaciers retreated, a
corridor opened on the eastern slopes of the
Rocky Mountains allowing passage to the
south. By 10,000 years ago, western Canada
was ice-free but central and eastern Canada
remained covered by the Laurentide ice
sheet and large proglacial lakes (Fig. 7).
Passage to eastern Canada north of the
Great Lakes was impossible at this time and
the only dispersal corridor was south of the
lakes. By 8,400 years ago, moose arriving
in the eastern continent could have dis-
persed westward north of the lakes, skirting
the southern shores of the proglacial lakes
to the north, and come into secondary con-
tact with moose from the west once the
proglacial lakes receded. Moose in the
eastern part of the continent (A. a.
americana) would have been on the end of
a series of founder events, explaining their
low mitochondrial variability and the pres-
ence of a contact zone between A. a.
americana and the much more variable A.
a. andersoni in Ontario between the Great
Lakes and Hudson Bay.
Morphological Adaptation
Moose of the Pleistocene and those that
entered North America at the beginning of
the Holocene were significantly larger than
those living today, a trait shared with other
northern ruminants (Guthrie 1984). Guthrie
(1984) proposed that the reduction in body
size was an adaptation to changes in sea-
sonal forage availability that occurred as a
result of climate amelioration at the end of
the last ice age. The ability of moose to
respond to a rapidly changing environment
belies the relatively low levels of genetic
variation documented by the studies we
have reviewed and demonstrates that evo-
lutionary potential is not easily predicted
solely by genetic variability but ultimately is
determined by the presence of adaptive
genetic variation and heritability of traits
that improve fitness (Lynch 1996).
A general reduction in body size is not
the only change to occur since the coloniza-
tion of North America. Moose in
Fig. 7. Coverage of North America by the
Cordilleran and Laurentide ice sheets and
proglacial lakes at 14,000, 10,000, and 8,400
years ago (adapted from Dyke and Prest 1987).
North America exhibit many differences in
behavior and morphology. Alaskan moose
are perhaps the most divergent; they exhibit
a degree of sociality not observed else-
where (Molvar and Bowyer 1994) and have
more distinctive body markings, also indica-
tive of increased sociality (Bowyer et al.
1991). Molvar and Bowyer (1994) sug-
gested that moose in Alaska have evolved
sociality recently as a response to living in
open environments. Adaptation to open
environments also applies to their mating
system, which is harem-based. Harem
mating is adaptive in open environments
(Hirth 1977) where a male can protect a
harem from competitors. Moose elsewhere
in North America exhibit a tending-bond
system of mating, which is adaptive for
forested environments.
Moose in Alaska and Siberia exhibit the
largest body size of moose in North America
and Eurasia, respectively. The similar ap-
pearance of moose occurring on either side
of the Bering Strait has caused some inves-
tigators to consider them the same subspe-
cies (e.g., Telfer 1984). As moose from
those 2 regions are not closely related
(Hundertmark et al. 2002a,b), their similar-
ity in size must result from convergent evo-
lution. Both subspecies have adapted to
open, northern habitats by increasing body
size. Adaptation to open habitats was dem-
onstrated with a multivariate analysis of
antler size among moose inhabiting differ-
ent areas and habitats in Alaska (Bowyer et
al. 2002). Those moose inhabiting open
habitats (tundra) tended to have larger ant-
lers overall than those living in boreal forest
(taiga). Similarly, moose occupying moun-
tainous habitat in the southern portions of
their range in North America (A. a. shirasi)
and Asia (A. a. cameloides) are similar;
exhibiting small body and antler size (Geist
1998). Bubenik (1998) explained that simi-
larity by proposing a second entry into North
America by Asian moose—an entry that
bypassed Beringia by traveling along the
southern coast of Alaska. Neither genetic
nor fossil data support that hypothesis
(Guthrie 1990, Hundertmark et al. 2002a,b,
To this point we have discussed distri-
bution of genetic and morphological diver-
sity over space and time in the context of
genetic drift and selection for locally adap-
tive traits. Those patterns are developed
over relatively long periods of time and are
integral to the process of evolution. Genetic
change also can occur over short periods
due to human influences, notably harvest
management, and those changes may have
unintended and undesirable consequences
on individuals and populations (Harris et al.
2002) and therefore are important to recog-
Although it might be assumed that a
well-designed harvest plan acts in a random
fashion on genetic makeup of individuals, in
reality even a managed harvest can be a
highly selective force with measurable con-
sequences in just a few generations
(Coltman et al. 2003). Ryman et al. (1981)
modeled the effect of different harvest strat-
egies on 2 factors critical in determining the
extent of genetic drift and inbreeding in
populations: effective population size and
generation interval, respectively. Hunt-
ing strategies were defined by different
probabilities of harvest for both juveniles
and adult females, and resulted in stable
populations with decreased generation in-
tervals and effective sizes compared with
unhunted populations. Moreover, temporal
changes in genetic diversity differed for
different harvest strategies but always de-
creased. Thus, Ryman et al. (1981) demon-
strated that improperly designed harvest
regimes can affect genetic characteristics
of populations and by extension may have
an influence on evolutionary potential. Con-
versely, Cronin et al. (2001) detected no
differences in numbers of alleles or levels
of heterozygosity for 5 microsatellite loci
among 3 moose populations in Quebec, 1
heavily hunted, 1 lightly hunted, and 1 not
Another critical factor in management
is the effect of harvest on genetic loci
underlying characters having a direct effect
on reproductive fitness, e.g., antler size in
moose. Controlling harvest by defining
legal males according to antler size is com-
mon in management of North American elk
(Thelen 1991) and is a strategy employed in
moose management in British Columbia,
Canada, and Alaska, USA (Child 1983,
Schwartz et al. 1992). In an effort to
evaluate genetic effects of the selective
harvest system in Alaska, Hundertmark et
al. (1993, 1998) modeled moose populations
subject to harvest strategies employing dif-
ferent definitions of legal males. They
concluded that selective harvest systems
could result in allele frequency changes at
loci coding for antler characteristics
(Hundertmark et al. 1993) and that the
position of a population relative to nutri-
tional carrying capacity of the habitat af-
fected the rate of change in allele frequen-
cies (Hundertmark et al. 1998). Those
results indicated that limiting harvest to
moose with large antlers could cause a
genetically based decrease in antler size
over time. Such a reduction in adaptive
genetic variation runs counter to general
conservation goals (Lynch 1996). A stun-
ning example of the effect of harvest on
fitness traits was recently reported by
Coltman et al. (2003), who documented
significant genetic effects on horn size and
body mass in bighorn sheep (Ovis
canadensis) as a result of selective harvest
of males with large horns.
Detecting potential changes in genetic
composition of moose as they respond to
various anthropogenic influences, whether
related to management or to changes in the
environment, is a difficult task. Nonethe-
less, it is an important area of investigation
and deserves attention. Modeling exercises
and studies of genetic variation have not
addressed interrelationships of moose
populations at fine scales. The effects of
management and habitat alteration on proc-
esses involved in maintenance of connec-
tivity of moose populations, such as male-
mediated gene flow via yearling dispersal
are extremely important and should be de-
scribed. Moose are highly adaptable ani-
mals, but the intensive management of moose
populations and the environmental factors
influencing their habitat (e.g., wildfire) may
have unintended and significant conse-
quences on the moose genome through a
change in selective forces. Proper conser-
vation of this species requires that we rec-
ognize and avoid that possibility.
We thank the organizers of the 5th Inter-
national Moose Symposium for the opportu-
nity to synthesize and present this informa-
tion. We wish to acknowledge funding sup-
port from Federal Aid in Wildlife Restora-
tion through the Alaska Department of Fish
and Game as well as the Institute of Arctic
Biology, University of Alaska Fairbanks. S.
Côté and an anonymous reviewer provided
constructive comments for improving the
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Term Definition
Adaptive genetic variation Genotypic variation at loci that control traits important to fitness, such as morphology,
physiology, and behavior.
Allozyme A gene product (protein) that is distinguished by its migratory characteristics in a gel
exposed to an electric field (electrophoresis). Differences among alleles (different variants
of the same gene) at allozyme loci relate to amino acid composition and secondary
structure of the protein. Only mutations that create proteins with different migratory
characteristics are detectable.
Control region A portion of mtDNA that evolves (incorporates mutations) at a very fast rate, which makes
it a valuable marker for examining intraspecific genetic variation. Occasionally referred to
as the D-loop.
DNA sequence The ultimate level of analysis of genetic material. This technique deduces the identity and
order of nucleotides in a fragment of DNA. Mutations (nucleotide substitutions) are
detectable whether or not they create different gene products.
Effective population size The size of a standardized population that has the same degree of genetic drift as the
population being studied. An ideal population is a closed population of constant size with
non-overlapping generations and no variance in reproductive success. The smaller the
effective size of a population, the faster it will lose genetic diversity through drift
regardless of actual population size. Effective population size (Ne) is almost always a
fraction of the true population size (N).
Generation interval Mean age of all parents.
Genetic drift Changes in allele frequencies across generations due to random sampling error associated
with less than infinite population size.
Haplotype The haploid equivalent of genotype. Genetic type of an individual when haploid DNA,
such as mtDNA, is analyzed.
Heritability The proportion of variance in the expression of a trait, such as antler size or body size, that
is due to genetic effects (as opposed to environmental effects), i.e., the degree to which a
trait can be passed on to the next generation.
Microsatellite Segments of DNA composed of sequence units varying from 2-4 nucleotides in length that
are tandemly repeated. Size variation (number of repeated units) defines alleles.
Microsatellites are Mendelian in their inheritance, i.e., they are diploid, specific to a site on
a chromosome, and occur in either a homozygous or heterozygous genotype.
Minisatellite Similar to microsatellites except that the repeat units vary from 16-64 nucleotides in length
and occur at many sites throughout the chromosomes, thus exhibiting more than 2 alleles
per individual and creating complex genotypes of gel banding patterns that resemble bar
codes. This is the technique that pioneered genetic fingerprinting.
Mitochondrial DNA (mtDNA) A circular DNA molecule occurring in the mitochondrion. Unlike chromosomes, which
occur in pairs (diploid), mtDNA occurs as a single copy (haploid) because it is inherited
only from the maternal line. Therefore, it is not subject to recombination and changes only
via mutation. That property makes it particularly useful for tracing lineages through time.
Molecular clock The assumption that the average rate of mutation for a particular DNA sequence is
constant over evolutionary time. If a molecular clock can be assumed, the amount of
genetic divergence between populations or species can be converted to time since
Phylogeography The study of genetic lineages in a spatial and temporal context, revealing historic
population processes and evolutionary histories.
RFLP Restriction Fragment Length Polymorphism – a section of DNA of known length is
digested with restriction enzymes (endonucleases), which cleave DNA at sites with
specific target sequences of 4-6 nucleotides. The digested fragments are separated by
length (number of nucleotides) using gel electrophoresis and haplotypes are characterized
by numbers and sizes of fragments.
Appendix 1. Glossary of specialized terms used in this review.
... Moose (Alces alces) are the sole extant members of the Alces genus and are widely distributed among subarctic regions of the northern hemisphere (Geist 1998;Hundertmark and Bowyer 2004). In North America, four subspecies have been described based on biogeography and morphology (Peterson 1955;Hall 1981), with three of the subspecies' boundaries extending south into the contiguous United States (U.S.): A. a. shirasi (Shiras moose), A. a. andersoni (Western moose), and A. a. americana (Eastern moose), and the fourth subspecies, A. a. gigas (Alaskan moose), inhabiting Alaska and northwestern Canada (Fig. 1). ...
... The subsequent reduction in genetic diversity may reduce the fitness of individuals and the evolutionary potential of a species, thereby increasing the probability of population extinction (Bouzat 2010;Bijlsma and Loeschcke 2012;Mimura et al. 2017). Low genetic diversity is a known trait among the North American moose populations and likely reminiscent of a founder effect (Hundertmark and Bowyer 2004). The North American moose population is estimated to have been founded 11 to 14 Ka as a small population of moose entered the Americas via the Beringian land bridge (Guthrie 1995;Hundertmark et al. 2002b;Meiri et al. 2014). ...
... Since the 1990's, genetic studies of moose have relied on cytogenic, mitochondrial DNA (mtDNA), and microsatellite markers to investigate genetic structure and subspecies designations (Boeskorov 1997;Hundertmark et al. 2002aHundertmark et al. , 2003Hundertmark and Bowyer 2004;DeCesare et al. 2020), though genome-wide analyses are rare (e.g., Kalbfleisch et al. 2018). While mtDNA and microsatellites have been useful for elucidating subspecies boundaries, the use of genomic techniques provides increased capability for local-scale analysis that can better inform state and regional conservation and management planning (e.g., Funk et al. 2012Funk et al. , 2019Coates et al. 2018). ...
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Genome-wide evaluations of genetic diversity and population structure are important for informing management and conservation of trailing-edge populations. North American moose (Alces alces) are declining along portions of the southern edge of their range due to disease, species interactions, and marginal habitat, all of which may be exacerbated by climate change. We employed a genotyping by sequencing (GBS) approach in an effort to collect baseline information on the genetic variation of moose inhabiting the species’ southern range periphery in the contiguous United States. We identified 1920 single nucleotide polymorphisms (SNPs) from 155 moose representing three subspecies from five states: A. a. americana (New Hampshire), A. a. andersoni (Minnesota), and A. a. shirasi (Idaho, Montana, and Wyoming). Molecular analyses supported three geographically isolated clusters, congruent with currently recognized subspecies. Additionally, while moderately low genetic diversity was observed, there was little evidence of inbreeding. Results also indicated > 20% shared ancestry proportions between A. a. shirasi samples from northern Montana and A. a. andersoni samples from Minnesota, indicating a putative hybrid zone warranting further investigation. GBS has proven to be a simple and effective method for genome-wide SNP discovery in moose and provides robust data for informing herd management and conservation priorities. With increasing disease, predation, and climate related pressure on range edge moose populations in the United States, the use of SNP data to identify gene flow between subspecies may prove a powerful tool for moose management and recovery, particularly if hybrid moose are more able to adapt.
... The North American and some of the eastern Asian group also lack a 75 bp section of the mtDNA CR. At present, the geographical border between specimens expressing these differences in Asia is poorly defined (Hundertmark & Bowyer, 2004;Nemoikina, Kholodova, Tyutenkov, & Moskvitina, 2016;Niedziałkowska, 2017). ...
... North American moose comprise only one haplogroup (Hundertmark & Bowyer, 2004) while the east Asian region contains all three or four reported haplogroups of moose worldwide Hundertmark, Shields, Udina, et al., 2002). However, North American moose share no haplotypes with the geographically closest moose population, on the Asian side of the Bering Strait in northeast Siberia. ...
... Moose, as a boreal species, might be expected to be confined to southern refugia during the LGM, and to move northwards during interstadials and interglacials. Hundertmark and Bowyer (2004) suggested a single refugium around southern Yakutia (ca. 60°N). ...
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Aim Late Quaternary climate oscillations had major impacts on species distributions and abundances across the northern Holarctic. While many large mammals in this region went extinct towards the end of the Quaternary, some species survived and flourished. Here, we examine population dynamics and range shifts of one of the most widely distributed of these, the moose (Alces alces ). Location Northern Holarctic. Taxon Moose (A. alces ). Methods We collected samples of modern and ancient moose from across their present and former range. We assessed their phylogeographical relations using part of the mitochondrial DNA in conjunction with radiocarbon dating to investigate the history of A. alces during the last glacial. Results This species has a relatively shallow history, with the most recent common ancestor estimated at ca. 150–50 kyr. Ancient samples corroborate that its region of greatest diversity is in east Asia, supporting proposals that this is the region of origin of all extant moose. Both eastern and western haplogroups occur in the Ural Mountains during the last glacial period, implying a broader contact zone than previously proposed. It seems that this species went extinct over much of its northern range during the last glacial maximum (LGM) and recolonized the region with climate warming beginning around 15,000 yr bp . The post‐LGM expansion included a movement from northeast Siberia to North America via Beringia, although the northeast Siberian source population is not the one currently occupying that area. Main conclusions Moose are a relatively recently evolved species but have had a dynamic history. As a large‐bodied subarctic browsing species, they were seemingly confined to refugia during full‐glacial periods and expanded their range northwards when the boreal forest returned after the LGM. The main modern phylogeographical division is ancient, though its boundary has not remained constant. Moose population expansion into America was roughly synchronous with human and red deer expansion.
... The genus Alces contains one species, divided into six (according to Whitehead 1993) to eight (Dzięciołowski and Pielowski 1993;Hundertmark 2016) or nine subspecies: Alces alces alces (Linnaeus, 1758) in Europe and Asia: A. a. cameloides Milne-Edwards 1867, A. a. pfizenmayeri Żukowski 1910, A. a. buturlini (division according to Hundertmark 2016), and A. a. caucasicus Verestsagin 1955 (extinct since the nineteenth century) in Asia, and the other four in North America (Peterson 1955). Hundertmark and Bowyer (2004) provided a distribution map of the eight extant subspecies. This division into subspecies is based on morphology and geographic distribution. ...
... The overall nucleotide diversity (π) was also the highest in Asian moose population (π ¼ 0.019, Hundertmark et al. 2002) in comparison with European (π ¼ 0.013, Niedziałkowska et al. 2014) and North American (π ¼ 0.007, Hundertmark et al. 2002) populations, which is probably a result of the ancestral character of the Asiatic population of the species (Hundertmark et al. 2002;Meiri et al. 2020). Moreover, both European and the North American populations suffered from founder effects and bottlenecks in the past as consequences of climatic oscillations and overhunting (Hundertmark et al. 2002;Hundertmark and Bowyer 2004;Niedziałkowska et al. 2014;Dussex et al. 2020). Also, the European moose mtDNA lineage differs from Asian and American mtDNA lineages by a 75-bp length mutation (indel, insertion in European sequences or deletion in Asian-American sequences) within the control region of mtDNA (Hundertmark et al. 2002;Niedziałkowska et al. 2014;Meiri et al. 2020). ...
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This comprehensive species-specific chapter covers all aspects of the mammalian biology, including palaeontology, physiology, genetics, reproduction and development, ecology, habitat, diet, mortality, and behavior. The economic significance and management of mammals and future challenges for research and conservation are addressed as well. The chapter includes a distribution map, a photograph of the animal, and a list of key literature.
... We found that the majority of ROH were short (< 2 Mb) in all moose genomes, which indicates that most of the observed inbreeding is due to background relatedness [53,54], potentially resulting from glacial or post-glacial bottleneck events [17,20,28,43]. For example, the three American samples showed the highest background inbreeding and lowest diversity, consistent with a single or several founder effects when colonizing North America at the end of the last glaciation [27]. ...
... The modern Swedish moose belongs to the Western European clade. Even though limited to one sample, this supports the hypothesis that contemporary Scandinavian moose originate from a refugial population in western/central Europe via a southern colonization that happened after the last glaciation[43]. In fact, our oldest ancient moose sample from Germany, Meng37 (10 ka BP), is also part of this Western clade, indicating that this clade was present in central Europe at the onset of the Holocene. ...
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Background Numerous megafauna species from northern latitudes went extinct during the Pleistocene/Holocene transition as a result of climate-induced habitat changes. However, several ungulate species managed to successfully track their habitats during this period to eventually flourish and recolonise the holarctic regions. So far, the genomic impacts of these climate fluctuations on ungulates from high latitudes have been little explored. Here, we assemble a de-novo genome for the European moose (Alces alces) and analyse it together with re-sequenced nuclear genomes and ancient and modern mitogenomes from across the moose range in Eurasia and North America. Results We found that moose demographic history was greatly influenced by glacial cycles, with demographic responses to the Pleistocene/Holocene transition similar to other temperate ungulates. Our results further support that modern moose lineages trace their origin back to populations that inhabited distinct glacial refugia during the Last Glacial Maximum (LGM). Finally, we found that present day moose in Europe and North America show low to moderate inbreeding levels resulting from post-glacial bottlenecks and founder effects, but no evidence for recent inbreeding resulting from human-induced population declines. Conclusions Taken together, our results highlight the dynamic recent evolutionary history of the moose and provide an important resource for further genomic studies.
... Furthermore, the nominate subspecies, A.a.alces (the European moose), has a karyotype of 2N = 68 while the other subspecies, sometimes referred to as the American moose group, have 2N = 70, which is why a split into two separate species has been suggested (Boeskorov et al. 1996, Boeskorov 1997). Yet, these moose karyotypes live sympatrically in Western Siberia, with no verified reproductive isolation, keeping the debate unsettled for the present (Hundertmark & Bowyer 2004). In this thesis, the name 'moose' is used narrowly, referring only to the European subspecies (unless stated otherwise), for simplicity. ...
... According to the present knowledge, the modern moose originated in Asia approximately 100,000 years ago (Lister 1993), from where it spread to Europe and North America during the Late Pleistocene (Hundertmark & Bowyer 2004). However, during the Last Glacial Maximum (c. ...
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Spatial and temporal variation is a universal feature in most organisms in nature, commonly reflecting the past evolutionary history of the species as well as the prevailing environmental conditions. The purpose of this doctoral thesis study was to investigate the genetic and phenotypic variation, and to assess the roles of the different processes affecting them in the moose (Alces alces). Altogether 809 DNA samples of moose, gathered throughout Finland and the Republic of Karelia in Russia, were analysed with a variety of population genetic methods. Furthermore, the shape of the moose mandible was investigated with the help of geometric morphometrics using a subset of samples gathered from 179 moose in Finland. This study showed that the Finnish and especially the Karelian moose population harboured relatively high genetic diversity, albeit with clear regional differences in its spatial distribution. In the northern half of Finland, a secondary contact of two diverged mitochondrial lineages was revealed. The presence of the two lineages was interpreted to reflect the existence of allopatric refugia of moose during the Last Glacial Maximum and the subsequent bi-directional recolonisation of Fennoscandia. Furthermore, a spatially explicit Bayesian clustering analysis suggested existence of three genetic clusters, which were estimated to have split after the post-glacial recolonisation. The results also showed that past declines in the moose numbers during the 18th and 19th centuries led to population bottlenecks, leaving a genetic imprint. Thus, the present moose population in eastern Fennoscandia carries the signs of both ancient and more recent events in its genetic composition. Finally, a significant latitudinal shift was revealed in the shape of the moose mandible. The pattern was considered independent of the genetic clustering of the population. The main changes included an enlargement of the attachment surfaces of the muscles controlling biting and mastication, implying more effective mastication in the north compared with the south, possibly an adaptive response to a longer period of hard wintertime diet. The results of this thesis encourage continuation of studies on the moose in order to fully reveal the impact of particular historical events and especially anthropogenic factors on the genetic and phenotypic variation of this species. They also provide the starting point for ‘genetically enlightened’ moose management and conservation in Finland.
... The moose (Alces alces), the largest species of cervid, inhabits the boreal forests of central and northern Europe, northern America and Asia [8]. The southernmost area of its distribution runs through Poland, which is also the western border of its European range [9]. ...
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Parasitic infections have a negative impact on the fecundity and survival of wild ruminants,particularly moose; however, despite being more susceptible to parasitic diseases than other wildcervids, they remain poorly examined in this regard. Therefore, the aim of the present study wasto identify gastrointestinal and liver helminth species of the moose population in central Europe,assess the factors contributing to infection intensities and examine their impact on moose health.Abomasum, small intestine, caecum and liver samples were collected from 46 moose in Poland andevaluated for helminth parasite fauna and histopathological changes. Additionally, 289 moose fecalsamples were analyzed for the presence of eggs, oocysts and larvae of parasites. In total, 19 parasitetaxa were identified. The most prevalent wereMazamastrongylus dagestanicaandOstertagia antipini,which are typical nematodes of moose, together withSpiculopteragia boehmiandO. leptospicularis,characteristic also of other cervids. Parasite species diversity and abomasal parasitic infectionintensity were higher in adult moose than in yearlings and calves. The numbers of histopathologicallesions depended on the intensity of parasitic infections, and were most severe in the livers of mooseinfected withParafasciolopsis fasciolaemorpha. The analysis of fecal samples revealed several regionaldifferences in the levels of parasite eggs, oocysts and larvae shedding. Our findings indicate anaccumulation of parasite infections over time in moose, which may be related to high environmentalparasite pressure, possibly connected with high moose density and the presence of wetlands; theyalso serve as the most comprehensive study of moose parasites in central Europe to date.
... The moose is a large mammalian herbivore inhabiting northern Europe, Siberia and north America (Hundertmark and Bowyer, 2004). Exploitation of the species in Poland in the 1970s and 80s resulted in a decline in the moose population by over 70%, and the subsequent imposition of a ban on moose hunting in 2001. ...
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Lungworms from the genus Dictyocaulus are the causative agents of verminous pneumonia in domestic and wild ungulates. Recently, in 2017, a new species was isolated from red deer and described as Dictyocaulus cervi; however, little is known about its epidemiology and pathogenicity in other cervids. The aim of our study was to determine the extent of infection with Dictyocaulus nematodes in the moose population in Poland. Parasitological necropsies were performed in 18 moose and 249 faecal samples were analysed. A combination of multiplex PCR and analysis of the partial SSU, cox1 and cyt B regions revealed the presence of D. cervi infection in two of the necropsied moose. Histopathological examinations revealed changes, including multiple cross sections of larvae of nematodes in alveoli, massive pulmonary fibrosis, mononuclear cell infiltration and diffuse alveolar damage in the lungs of four animals. The lesions were more pronounced when adult Dictyocaulus nematodes were present in the bronchi and bronchioles. Some of the observed pathological changes could be attributed to co-infection by nematodes of the Protostrongylidae, whose larvae were found in all four animals with lung pathologies. In the faeces, Dictyocaulus sp. larvae only occurred together with Protostrongylidae larvae; in addition, higher numbers of Protostrongylidae larvae were excreted in the faeces of animals with dictyocaulosis. The present study is the first report of the presence of D. cervi in moose, and demonstrates the value of multiplex PCR in the identification of Dictyocaulus nematodes. Our findings indicate that co-infections with multiple species of lung nematodes in moose may be commonplace, and this should be considered as a factor aggravating the course of parasitosis.
... The moose (Alces alces) is a large, sexually size-dimorphic, boreal ungulate with a vast area of distribution throughout the Holarctic region (Garel et al. 2006). Currently, the species is divided into up to eight subspecies displaying differences in body size, coloration, and behavior, some of which are considered as ecological adaptations to the major habitat types within the moose range, i.e., tundra, boreal forests, and alpine areas (Peterson 1955;Geist 1987;Hundertmark and Bowyer 2004;Lister 2005). However, the masticatory system of the moose is globally regarded to show strict specialization (Breda 2010). ...
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Intra-specific geographic variation is probably one of the most common patterns studied in ungulate morphology. However, the shape of the mandible, a crucial feature with regard to feeding, has been greatly understudied in this context. Here, we utilized a museum collection of moose (Alces alces) mandibles to investigate whether we could detect significant variation in this species, and test for the existence of geographic patterns and associations with population genetic structure. We applied a landmark-based geometric morphometrics approach, analyzing shape data with principal component analysis and linear mixed models. A significant geographic shift in the shape of the moose mandible was revealed. The main pattern was similar in both sexes; however, there was a consistent difference in shape between males and females over the latitudinal scale. The main changes included an enlargement in the attachment surfaces of the muscles controlling biting and mastication, suggesting more effective mastication towards the north, plausibly as an adaptive response to a harder and tougher wintertime diet. Additionally, more subtle, yet statistically significant age-related shape variation was discovered. Interestingly, no or only a weak association between the morphometric variation and the genetic population structure was detected with neutral molecular markers.
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The study analyses patterns of endoparasite eggs, oocysts and larvae shedding by moose from the relict population in the Biebrza marshland, NE Poland, which has grown to be one of the largest in Central Europe since the ban on hunting imposed in 2001. The analysis identified 10 species or groups of parasites among 230 faecal moose samples collected over 16 consequent months. The most prevalent were the eggs of Trichostrongylidae, Trichuris spp., Nematodirella alcidis, Parafasciolopsis fasciolaemorpha and the larvae of Elaphostrongylus sp. Four parasite species were more prevalent in males, indicating male-biased parasitism, and the studied moose population exhibited a female-skewed sex ratio. Nematodirella alcidis eggs and Protostrongylid larvae were more prevalent during winter, which indicated their resistance to harsh weather conditions. The prevalence of Eimeria alces and Aonchotheca sp. increased during the growing season, as did the number of eggs per gram of faeces (EPG) of P. fasciolaemorpha, possibly due to the availability of water sources. Higher mean monthly temperature was also found to have a positive effect on the excretion of Trichostrongylidae and Moniezia spp. eggs. In addition, the time of infection and the specificity of the parasite life cycle, being sensitive to certain climatic conditions, also appeared to have a strong influence on eggs, oocysts and larvae shedding in this non-harvested moose population.
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The Arctic tundra biome has had a brief but highly variable history of formation compared with other world biomes, culminating in the modern northern flora and fauna that collectively maintain biodiversity connections on a global scale. Terrestrial Arctic tundra mammals constitute a fauna of approximately 80 species, to varying degrees adapted for life north of treeline. In addition to specializations for cold environments, Arctic mammals have evolved in response to dramatic climate cycling through the last 3 million years of the Quaternary period, developing life histories that reflect changing associations with other species and other biomes through time. This article focuses on evolutionary development of the modern Arctic tundra mammal assemblage, the environmental processes that have influenced their diversity and distribution across the northern hemisphere through time, and their collective ecology that drives continued community changes. In modern times, the Arctic is experiencing climate warming and associated anthropogenic environmental disturbances that are approaching the limits of what tundra mammals have experienced at any time through the history of this biome. Continued persistence of mammals within the Arctic tundra will depend on resilience and plasticity among species, and on concerted efforts by us to understand the processes that impact Arctic biodiversity in general. By doing so, scientists may anticipate focal species, local communities, or geographic regions at highest risk of population declines, investigate the consequences of changing species associations for competition, future evolutionary potential, and spread of disease, and ultimately manage and conserve these ecosystems and tundra wildlife more effectively.
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Intraspecific variation in mitochondrial DNA of North American cervids was assessed with restriction enzymes to determine relationships among populations and subspecies. No variation was detected in moose (Alces alces) and little in elk (Cervus elaphus). Caribou (Rangifer tarandus), white-tailed deer (Odocoileus virginianus), and mule deer (Odocoileus hemionus) possessed considerable variation. Characteristic genotypes exist in caribou and white-tailed deer from different geographic areas although subspecies are not discernable as distinct mtDNA assemblages. Except for O. hemionus, intraspecific mtDNA sequence divergences are small (< 2%). Subspecies of mule deer have divergent mtDNA (7%) and are the only subspecies of cervids with distinct genotypes.