
David TarkhnishviliIlia State University | ISU · Institute of Ecology
David Tarkhnishvili
Doctor of Philosophy
About
147
Publications
60,060
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Introduction
Dean of School of Natural Sciences and Engineering, Head of the Ilia State University Institute of Ecology, lab of the Quantitative Ecology
Scientific interests / research interests: Evolutionary biology, Speciation, Population ecology and genetics, Ecological modeling,
Biogeography, Human population genetics, Caucasus
Graduated from Tbilisi State University (Biology, zoology) (1982). PhD in Ecology from Research Inst. of Ecology, Ural Sci. Center at Sverdlovsk (pres. Ekaterinsburg), Russia, 1987. Research – interspecific competition of amphibians. Work experience – Tbilisi State University, Vietnam Tropical Center (1990), Bangor University, UK (1996-1997, post-doctoral fellow), Zoological Research Institute and Museum Al. Koenig, Bonn, Germany (1998; 1999-2003; post-doctoral fellow, researcher).Studies mostly in ecology, biogeography, population genetics and evolution of amphibians and reptiles. Over 100 published research papers. At Ilia State since 2006, employed as a dean of the school of Life Sciences, director of the Institute of Ecology, and dean of the School of Science and Engineering.
Teaching:
An introductory course “Evolution – From Darwin to Present: Facts and Theories”; BSc course “Essentials of Ecology”; “Statistics for Biologists” (MSc) and “Population Ecology and Genetics” (MSc)
Taught within BSc and MSc programs in Biology and Ecology
Additional affiliations
September 1996 - September 1997
January 2009 - December 2010
January 2008 - December 2012
Publications
Publications (147)
The second edition of the Caucasus Environment Outlook (CEO-2) emphasizes in its nine chapters the importance of regional environmental monitoring through a participatory and consultative approach. It explores the latest regional developments and environmental assessments in terms of population, urbanization, economic development, climate change, l...
A recent revision of the anacondas (Serpentes: Boidae: Eunectes), with the description of a new species of green anaconda, generated extensive publicity, but also provoked considerable controversy due to inadequacies of the evidence used and errors in nomenclature. We here use the case of this problematic publication to: (i) highlight common issues...
Large‐scale barcoding projects help to aggregate information on genetic variability of multiple species throughout their ranges. Comparing DNA sequences of both non‐conspecific and conspecific individuals from distant parts of their ranges helps to compare level of genetic isolation‐by‐distance patterns in different species and adaptive types. We c...
Two nominal species of water frogs of the genus Pelophylax, P. ridibundus and P. bedriagae, are found in Central and Eastern Europe, the Middle East, Western Asia, Western Kazakhstan, and Siberia. So far, the taxonomic status of Pelophylax in most of the Caucasus has remained unknown. Sequencing of the Cytochrome Oxidase 1 mitochondrial gene attrib...
Despite the increasing deficit of taxonomic expertise, the number of newly described species since the early 2010s has grown exponentially. This growth is related to the increased use of DNA markers in taxonomic descriptions. However, routine use of DNA markers in taxonomy did not bring practical taxonomy closer to the theory. Species are unique li...
Visual inspection of several embryos of the parthenogenetic lizard Darevskia armeniaca revealed the presence of an embryo with axial bifurcation (“two-headed”) on the stage of pigmented eyes and plate-like limb buds with a distinct border at the edges. This is the third recorded case of axial bifurcation in D. armeniaca, although two previous cases...
To assess the genetic structure of Ponto-Caspian brown trout (Salmo trutta complex) populations, we analyzed both mitochondrial DNA sequences and genotypes at 10 microsatellite loci of fish caught in the Black Sea and from nine river catchments in Georgia, flowing into either the Black or Caspian seas. The results show that: (1) there is substantia...
Caucasian rock lizards (Darevskia) are a speciose group with 42 described species from the Caucasus Mountain region. We selected 11 species from Georgia and adjacent territories to explore whether their distribution depends on the distribution of congeneric taxa. We estimated two measures for each species pair: (1) niche overlap between all pairs o...
The North American terrapin, the red-eared slider, has globally recognized invasive status. We built a new extensive database using our own original and literature data on the ecology of this reptile, representing information on 1477 water bodies throughout Eurasia over the last 50 years. The analysis reveals regions of
earliest introductions and l...
The genus Eunectes Wagler, 1830 is divided into four nominal species: E. murinus (Linnaeus, 1758), E. notaeus Cope, 1862, E. deschauenseei Dunn and Conant, 1936, and E. beniensis Dirksen, 2002 ( E. barbouri Dunn and Conant, 1936 being a synonym of E. murinus ). We analyze multivariate morphological traits (scalation, coloration pattern, and body sh...
We compared the life history components of small and large-bodied unisexual (Darevskia dahli and Darevskia armeniaca) and bisexual (Darevskia portschinskii, Darevskia valentini, and Darevskia obscura) Caucasian rock lizard species. Research objectives were to determine whether reproductive mode (bisexual or parthenogenetic), female body size, altit...
We genotyped multiple populations of all seven parthenogenetic species of rock lizards, genus Darevskia, as well as their putative sexual parental populations, using double digest RAD-sequencing genomic markers. Taking advantage of the conserved homology of the ZW/ZZ sex chromosomes among lacertid lizards, we aligned our short sequence reads to a r...
We genotyped multiple populations of all seven parthenogenetic species of rock lizards, genus Darevskia, as well as their putative sexual parental populations, using double digest RAD-sequencing genomic markers. Taking advantage of the conserved homology of the ZW/ZZ sex chromosomes among lacertid lizards, we aligned our short sequence reads to a r...
The analyses of 15 autosomal and 23 Y-chromosome DNA single-tandem-repeat loci in five rural populations from the Caucasus (four ethnically Georgian and one ethnically Armenian) indicated that two Georgian populations, one from the west and the other from the east of the Greater Caucasus Mountains, were both patrilineally and autosomally most diffe...
Biological invasions are recognized as one of the global problems accompanying the development of human civilization. The red-eared slider, Trachemys scripta elegans, originates from North America. This freshwater terrapin is one of the most popular pet reptiles in Eurasia. Young red-eared slider individuals are small and brightly colored, making t...
Reptiles contribute to the global process of biological invasions, one of the problems
accompanying the development of human civilization. The red-eared slider, Trachemys
scripta elegans is one of the most popular pet reptiles in the world. Uncontrolled releases of this animal into outdoor water bodies represents a conservational issue. We combined...
This study clarifies the role of refugia and landscape permeability in the formation of the current genetic structure of peoples of the Caucasus. We report novel genome-wide data for modern individuals from the Caucasus, and analyze them together with available Paleolithic and Mesolithic individuals from Eurasia and Africa in order (1) to link the...
Twentytwo snake species are recorded for Georgia. Over three years (2017-2019), social media (Facebook, iNaturalist and Instagram) was inspected to identify new snake records for Georgia. This led to an increase in the total number of known snake locations by 78% and this gain led to considerable growth of the Extent of Occurrence (up to 269%) and...
Two species of rock lizards, the parthenogenetic D. dahli and the sexually reproducing D. portschinskii , coexist in a rocky outcrop in an area of ca. 1 ha, in the vicinity of Tbilisi, Georgia; the location has been well-known since the middle 1960s. The population density of the parthenogenetic lizard is five times higher than that of the sexual b...
Grey wolf and golden jackal are both common in Georgia, although they have different habitat preferences. The wolf is more common in mountain areas of the country, and jackals are more common in the lowland part of Georgia, with its milder and warmer climate. In recent decades, the abundance of both species increased. Simultaneously, the jackals ar...
Background:
The majority of parthenogenetic vertebrates derive from hybridization between sexually reproducing species, but the exact number of hybridization events ancestral to currently extant clonal lineages is difficult to determine. Usually, we do not know whether the parental species are able to contribute their genes to the parthenogenetic...
The two species of rock lizards, Darevsia raddei and D. portschinskii, belong to two different phylogenetic clades of the same genus. They are supposed ancestors for the hybrid parthenogenetic, D. rostombekowi. The present study aims to identify morphological features of these two species and the potential gene introgression between them in the are...
We generated a phylogeny for Caucasian rock lizards (Darevskia), and included six other families of true lizards (Lacertini), based on complete mitochondrial genome analysis. Next-generation sequencing (NGS) of genomic DNA was used to obtain 16 new mitogenomes of Darevskia. These, along with 35 sequences downloaded from GenBank: genera Darevskia, Z...
Phenotypic evolution can cause either divergent or convergent phenotypic patterns. Even adaptation to the same environment may result in divergence of some elements of phenotype, whereas for other morphological traits it could cause phenotypic convergence. We hypothesize that at least some phenotypic characters diverge monotonically, hence they evo...
Three species of cetaceans, Phocoena phocoena, Delphinus delphis and Tursiops truncatus ponticus are found in the Black Sea. The Black Sea populations of all three species show morpho-ecological peculiarities that leaded to their subspecific status: P. p. relicta (PPR), D. d. ponticus (DDP), and T. t. ponticus (TTP). It is not clear how long-lastin...
The difference between phenotypic and genotypic differentiation of conspecific populations is commonly used for detecting natural selection. However, phenotypic variation integrates both genetic and non-genetic components, and this may lead researchers to false conclusions. To avoid bias, the analysis of the heritability of individual phenotypic ch...
Here we report on collaborative expeditions run by ISU (Ilia State University, Tbilisi), ZFMK (Zoologisches Forschungsmuseum Alexander Koenig, Bonn) and external taxonomists in Georgia in 2018 and 2019 as part of the renewed close cooperation between Germany and Caucasus countries aiming at the exploration of biodiversity in the Caucasus region. Th...
Attention to the special role of mountains has historically benefited enormously from sustained interaction between scientists, practitioners, and policy makers. The Caucasus Regional Research Agenda (C-RRA) is but the latest sign of these crucial and productive interactions. The C-RRA is the collective outcome of a dialogue among scientists from A...
ZIP-compressed map of the inferred biomes during the Last Glacial Maximum (LGM).
This map is in a raster Arc/Info binary format developed by ESRI (Environmental Systems Research
Institute). The binary format, also known as an ARC/INFO GRID or ARC GRID, can easily be viewed,
analyzed, processed and exported to different formats within ESRI programs...
Geometric morphometrics is a better tool to evaluate the variation of shape than ‘traditional’ morphometrics. In reptiles, it outperforms morphometrics based on linear measurements and scalation. In an earlier study, two-dimensional outline-based geometric morphometrics in six species of rock lizards (Darevskia) showed that their shapes reflected t...
Most researchers interpret genotypic diversity within some forms of parthenogenetic Darevskia as
indirect evidence of their polyclonal origin. Tarkhnishvili et al. (2017) showed that two parthenogens, both matrilineally descending from Darevskia mixta, share genotypes at two microsatellite loci. They concluded that a
single hybrid lineage participa...
Current taxonomy of western Eurasian trout leaves a number of questions open; it is not clear to what extent some species are distinct genetically and morphologically. The purpose of this paper was to explore phylogeography and species boundaries in freshwater and anadromous trout from the drainages of the Black and the Caspian Seas (Ponto-Caspian)...
The Lebanon Lizard (Phoenicolacerta laevis) occurs on the Levantine coast and scattered populations are found in isolated coastal habitats along the southern and south-western coast of Turkey. We found an isolated but dense population of this species at and around the castle of Anaklia on Georgia’s Black Sea Coast, near the mouth of the river Engur...
The analyses of 15 autosomal and 23 Y-chromosome DNA STR loci in five rural populations from the Caucasus, namely four ethnically Georgian and one ethnically Armenian populations, indicated that two populations of Georgians - one from the west and the other one from the east of the Greater Caucasus Mountains - were both patrilineally and autosomall...
The genus Darevskia comprises over 20 species of small-bodied lizards, mainly occurring in the Caucasus Mountain Region. They show differences in body size, scalation and coloration, however, fully diagnostic characters that could separate the species with a high confidence level are still lacking. The early phylogenetic hypothesis of this group wa...
The parthenogenetic lizards Darevskia armeniaca and Darevskia dahli are widespread throughout the Lesser Caucasus, although they occupy different habitats. While these forms differ in size, colour and scalation, both D. armeniaca and D. dahli have a hybrid origin and a common maternal progenitor species. Current evidence about the patrilineal origi...
The rock lizards of the Darevskia saxicola complex are found exclusively in the west of the Greater Caucasus and in southern Crimea. The earliest split within this group occurred between D. saxicola from the northern and D. brauneri from the southern slopes of the Greater Caucasus, followed by the split between D. brauneri and the Crimean D. lindho...
AimOur research attempts to provide an explicit explanation of human-biome interactions during the last glacial period and how these have influenced current human population genetics at the global scale. Publications to date have not addressed this topic. LocationWorld-wide. Methods
Using climate, terrain, hydrographic, fossil pollen and plant-macr...
The Caucasian rock lizard Darevskia mixta was sampled and studied from throughout its range, using mitochondrial cytochrome b sequences and scalation. The populations of the Greater and the Lesser Caucasus are reciprocally monophyletic matrilineally, and the respective lineages have been separated since the mid-Pleistocene. The lizards from the Gre...
As a result of intensive biodiversity research it became essential to accumulate existing
information and increasing it’s accessibility to researchers globally. In last two decades several
national and international biodiversity databases were created. In this paper we describe
development of Georgian biodiversity database (www.biodiversity-georgia...
The Caucasus is a mountain region located at the edge of Europe and Asia, between the Black and Caspian seas. In spite of limited geography and mostly temperate climate, diversity of natural landscapes, plant and animal species, and cultivated plants is unusually high. For these reasons, the Caucasus has been included in the list of global biodiver...
Publications that describe the human Y-DNA haplogroup composition
in different ethnic or linguistic groups and geographic regions provide no explicit
explanation of the distribution of human paternal lineages in relation to specific
ecological conditions. Our research attempts to address this topic for the Caucasus
– a geographic region that en...
We studied the distribution of the mitochondrial DNA haplotypes and microsatellite genotypes at 8 loci in 102 gray wolves, 57 livestock guarding dogs, and 9 mongrel dogs from Georgia (Caucasus). Most of the studied dogs had mitochondrial haplotypes clustered with presumably East Asian dog lineages, and most of the studied wolves had the haplotypes...
Two species of genus Helix Linnaeus, 1758 (Mollusca: Gastropoda: Helicidae) endemic to the Caucasus region are known from
Georgia and northeastern Turkey: Helix buchii Dubois de Montpereux, 1839 and the recently-described but disputed Helix goderdziana
Mumladze, Tarkhnishvili and Pokryszko, 2008. The latter species is the largest land snail throu...
Given sufficient time and limited gene flow, evolutionary lineages tend to transform into separate species. Mechanisms preventing assimilation during repeated gene-flow events include divergent adaptations and the development of pre- or postzygotic isolation. We analysed the morphological and genetic boundaries of three species of the rock lizard c...
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