Loren Cassin SackettUniversity of Louisiana at Lafayette | ULL · Department of Biology
Loren Cassin Sackett
PhD
Seeking grad students, especialmente hispanohablantes, to work on prairie dog genomics +conservation, disease, landscape
About
36
Publications
10,945
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Introduction
My research interests center around the evolution of small populations and the influence of pathogens on evolution of their hosts. I investigate the interactive effects of host genetic variation and dynamics of the introduced pathogen Yersinia pestis in fragmented populations of black-tailed prairie dogs in the western U.S. I am also working to characterize the genomic basis of tolerance to avian malaria among Hawaiian honeycreepers, and to understand constraints on adaptation to pathogens.
Additional affiliations
August 2014 - August 2014
Smithsonian National Zoological Park
Position
- Instructor
Description
- Developed a summer course on the ways in which humans influence evolution of plants and wildlife.
September 2006 - December 2012
June 2013 - July 2016
Education
September 2006 - December 2012
September 1999 - May 2003
Publications
Publications (36)
Introduced diseases can cause dramatic declines in-and even the loss of-natural populations. Extirpations may be followed by low recolonization rates, leading to inbreeding and a loss of genetic variation, with consequences on population viability. Conversely, extirpations may create vacant habitat patches that individuals from multiple source popu...
Population sizes of endemic songbirds on Kaua‘i have decreased by an order of magnitude over the past 10–15 years to dangerously low numbers. The primary cause appears to be the ascent of invasive mosquitoes and Plasmodium relictum, the agent of avian malaria, into elevations formerly free of introduced malarial parasites and their vectors. Given t...
Adaptation in nature is ubiquitous, yet characterizing its genomic basis is difficult because population demographics cause correlations with non‐adaptive loci. Introduction events provide opportunities to observe adaptation over known spatial and temporal scales, facilitating the identification of genes involved in adaptation. The pathogen causing...
Prairie dogs (genus Cynomys) are a charismatic symbol of the American West. Their large social aggregations and complex vocalizations have been the subject of scientific and popular interest for decades. A large body of literature has documented their role as keystone species of western North America's grasslands: They generate habitat for other ve...
Emerging infectious diseases are one of the foremost contemporary threats to biodiversity conservation. Outbreaks of novel pathogens can lead to extinction of host populations, loss of gene flow due to extirpation, and bottlenecks in host populations with surviving individuals. In outbreaks with survivors, pathogens can exert strong selection on ho...
The unprecedented rise in the number of new and emerging infectious diseases in the last quarter century pose direct threats to human and wildlife health. The introduction to the Hawaiian archipelago of Plasmodium relictum and the mosquito vector that transmits the parasite has led to dramatic losses in endemic Hawaiian forest bird species. Underst...
Soil microbial communities both reflect and influence biotic and abiotic processes occurring at or near the soil surface. Ecosystem engineers that physically alter the soil surface, such as burrowing ground squirrels, are expected to influence the distribution of soil microbial communities. Black-tailed prairie dogs (Cynomys ludovicianus) construct...
The malaria parasite Plasmodium relictum (lineage GRW4) was introduced less than a century ago to the native avifauna of Hawaiʻi, where it has since caused major declines of endemic bird populations. One of the native bird species that is frequently infected with GRW4 is the Hawaiʻi ʻamakihi (Chlorodrepanis virens). To achieve a better understandin...
Genomic resources are under-developed for rodents, including well-studied species such as prairie dogs (Cynomys spp.). We conducted whole-genome resequencing on 10 Gunnison’s prairie dogs (C. gunnisoni, GUPD) and identified 12,842,055 high-quality SNPs, from which four sets of bait sequences were created. We designed two sets each (containing eithe...
Genomic technologies continue to shed light on important ecological and evolutionary questions. Nonetheless, these new tools are applied disproportionately in a small fraction of global biodiversity, partly because of technical challenges to studying highly diverse taxa that occur in low abundances in an environment (e.g., marine and microbial comm...
The world’s birds are in trouble, and scientific research, including genetic and genomic methods, can play an important role in understanding and mitigating these problems. In this review, we summarize several ways that the concepts and methods of genomics can help with bird conservation and how the dramatically increasing power and decreasing cost...
Parasitism of mammals is ubiquitous, but the processes driving parasite aggregation on hosts are poorly understood, as each system seems to show unique correlations between parasitism and host traits such as sex, age, size and body mass. Genetic diversity is also posited to influence susceptibility to parasitism, and provides a quantifiable measure...
Species of restricted distribution are considered more vulnerable to extinction because of low levels of genetic variation relative to widespread taxa. Species of the subgenus Cynomys are an excellent system to compare genetic variation and degree of genetic structure in contrasting geographic distributions. We assessed levels of genetic variation,...
Preliminary findings on pre- and post-plague genetics in black-tailed prairie dogs
This is a script for simulating heterozygosity in a hypothetical population by drawing from values in real populations. Ho = observed heterozygosity preplague3 are the real heterozygosity values in 3 populations These data and the rationale are found in: L.C. Sackett, S.K. Collinge, A.P. Martin 2013. Do pathogens reduce genetic diversity of their h...
A script for heterozygosity randomization procedures, in this case, pre-plague vs. post-recolonization heterozygosity in each population separately Ho = average observed heterozygosity across loci for each individual These data and the rationale are found in: L.C. Sackett, S.K. Collinge, A.P. Martin 2013. Do pathogens reduce genetic diversity of th...
Background/Question/Methods
One of the principal goals of ecology and evolutionary biology is describing the mechanisms that lead to the diversity of life on earth. Our understanding of ecological divergence has improved greatly in the last several years; however, the ecological speciation literature is primarily focused on elucidating responses...
Connectivity of populations influences the degree to which species maintain genetic diversity and persist despite local extinctions. Natural landscape features are known to influence connectivity, but global anthropogenic landscape change underscores the importance of quantifying how human-modified landscapes disrupt connectivity of natural populat...
Since the identification and imprisonment of "Typhoid Mary," a woman who infected at least 47 people with typhoid in the early 1900s, epidemiologists have recognized that 'superspreading' hosts play a key role in disease epidemics. Such variability in transmission also exists among species within a community (amplification hosts) and among habitat...
Background/Question/Methods
One of the principal predictions of climate change models is an increase in extreme weather events, including heavy precipitation and exacerbated drought severity. Because these events could lead to dramatic changes in snowpack and soil moisture in alpine, Arctic, and Antarctic ecosystems, it is crucial to understand h...
Background/Question/Methods
Low temperatures, limited precipitation, and high salinity in the McMurdo Dry Valleys (MCM) of Antarctica constrain life to simple communities that are more easily interpreted in ecological studies. For these reasons, the MCM Long Term Ecological Research (LTER) site provides an ideal opportunity to address complex eco...
This article documents the addition of 238 microsatellite marker loci and 72 pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Adelges tsugae, Artemisia tridentata, Astroides calycularis, Azorella selago, Botryllus schlosseri, Botrylloides vio...
The suitability of the foliar N/P ratio was evaluated as a predictor of nutrient limitation in an alpine ecosystem of the Colorado Front Range. We hypothesized that foliar N/P ratios are directly correlated with the alpine soil nutrient status. We used a long-term fertilization experiment con- ducted in three alpine plant communities, where 48 plot...
Variations in science lab design can differentially impact student learning. Quantification of these differential
impacts can be used in modeling – an approach we term “optimal lab design.” In this study we estimated
relative influences of six characteristics of lab design on students’ attitudes toward science labs in three
different first-year col...
Questions
Questions (2)
I am looking for experimental evidence (or convincing non-experimental evidence) that the number of fleas or ticks an individual animal harbors is related to that individual's risk of infection by a vector-borne pathogen. Can anyone point me to some compelling literature?
I want to isolate mRNA from bird blood (nucleated blood cells), but haven't found a protocol that does that directly. Most of the protocols I've seen for blood entail a two step process: isolating total RNA, and then enriching for mRNA. On the other hand, there are non-blood protocols that can isolate mRNA directly. Does anyone know of a one-step protocol for getting mRNA from whole blood?
