Papers by David Tarkhnishvili
Amphibia-reptilia, Nov 2, 2022
microsatellite genotypes (number of nucleotides per STR allele) for 167 individual wolves and dog... more microsatellite genotypes (number of nucleotides per STR allele) for 167 individual wolves and dogs from Georgia (genotypes of wolves from the eastern and from the western Georgia shown separately). Microsoft Exel file, single spreadsheet
We studied the distribution of the mitochondrial DNA haplotypes and microsatellite genotypes at e... more We studied the distribution of the mitochondrial DNA haplotypes and microsatellite genotypes at eight loci in 102 grey 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 clustered with European wolves, but 20% of wolves and 37% of dogs shared the same mitochondrial haplotypes. Bayesian inference with STRUCTURE software suggested that over 13% of the studied wolves had detectable dog ancestry and over 10% of the dogs had detectable wolf ancestry. 2-3% of the sampled wolves and dogs were identified, with a high probability, as first generation hybrids. These results were supported by the relatedness analysis which showed that 10% of wolves and 20% of dogs had closest relatives from an opposite group. The results of the study suggest that wolf-dog hybridization is a common event in the areas where large livestock guarding dogs are held in a traditional way, and that gene flow between dogs and grey wolves was an important force influencing gene pool of dogs for millennia since early domestication events. This process may have been terminated (1) in areas outside the natural range of grey wolves and (2) since very recent time, when humans started to more tightly control contacts of purebred dogs
This document contains the draft Chapter 3 of the IPBES Global Assessment on Biodiversity and Eco... more This document contains the draft Chapter 3 of the IPBES Global Assessment on Biodiversity and Ecosystem Services. Governments and all observers at IPBES-7 had access to these draft chapters eight weeks prior to IPBES-7. Governments accepted the Chapters at IPBES-7 based on the understanding that revisions made to the SPM during the Plenary, as a result of the dialogue between Governments and scientists, wouldbe reflected in the final Chapters.IPBES typically releases its Chapters publicly only in their final form, which implies a delay of several months post Plenary. However, in light of the high interest for the Chapters, IPBES is releasing the six Chapters early (31 May 2019) in a draft form. Authors of the reports are currently working to reflect all the changes made to the Summary for Policymakers during the Plenary to the Chapters, and to perform final copyediting.
Herpetozoa, 2021
Two species of rock lizards, the parthenogenetic D. dahli and the sexually reproducing D. portsch... more 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 breeder. We studied the distribution of active lizards in space and time over three consecutive years, during the spring and autumn activity periods, to explore spatial and temporal differences between the species on a fine spatial scale. We studied the influence of temperature, humidity, and quantitative characteristics of the surface and the distance from permanent water source on the spatial distribution of D. dahli and D. portschinskii. Darevskia portschinskii was less dependent on the distance from the water source and more evenly distributed in space and time than D. dahli. Despite potential competitive interactions, the species did no...
Herpetological Journal, 2008
The Caucasian salamander (Mertensiella caucasica sensu lato) is an endemic taxon of the western L... more The Caucasian salamander (Mertensiella caucasica sensu lato) is an endemic taxon of the western Lesser Caucasus, classified as Vulnerable in the IUCN Red List. Two isolated evolutionary lineages occur within its range - one in the Black Sea basin, and the other in the basin of the Caspian Sea. We identified and described 51 locations throughout the range of the species, from the easternmost to the westernmost known location and within an elevational range of 50-2400 m a.s.l. We applied binary logistic regression and a maximum entropy approach to predict the range of the salamander within the polygon delimited by extreme values of 19 bioclimatic parameters for the locations identified. The models were based on the analysis ofbioclimatic data, terrain ruggedness and some other environmental variables. The presence or absence of the salamander depends on the level of and variations in rainfall, temperature and terrain ruggedness. Absence of the species from the Greater Caucasus is expl...
Herpetological Journal, 2016
The rock lizards of the Darevskia saxicola complex are found exclusively in the west of the Great... more 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. lindholmi, and the expansion of D. saxicola to the westernmost slopes of the Greater Caucasus. We collected nominal D. brauneri from the two easternmost populations of the species range: the valleys of the Tekhuri and Enguri rivers in Georgia. Analysis of mitochondrial DNA showed that the lizards from both valleys are deeply differentiated from each other and from previously characterised D. brauneri. Lizards from Tekhuri keep a basal position within the clade D. saxicola (excluding D. praticola), and lizards from Enguri are closer matrilineally to the northern Caucasian D. saxicola than to either of the populations of nominal D. brauneri. Tekhu...
BMC Evolutionary Biology, 2020
BackgroundThe majority of parthenogenetic vertebrates derive from hybridization between sexually ... more BackgroundThe 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 vertebrate lineages after the initial hybridization. In this paper, we address the hypothesis, whether some genotypes of seven phenotypically distinct parthenogenetic rock lizards (genusDarevskia) could have resulted from back-crosses of parthenogens with their presumed parental species. We also tried to identify, as precise as possible, the ancestral populations of all seven parthenogens.ResultsWe analysed partial mtDNA sequences and microsatellite genotypes of all seven parthenogens and their presumed ansectral species, sampled across the entire geographic range of parthenogenesis in this group. Our results confirm the previous designation ...
Zoologischer Anzeiger, 2020
The difference between phenotypic and genotypic differentiation of conspecific populations is com... more The difference between phenotypic and genotypic differentiation of conspecific populations is commonly used for detecting natural selection. However, phenotypic variation integrates both genetic and nongenetic components, and this may lead researchers to false conclusions. To avoid bias, the analysis of the heritability of individual phenotypic characters is important, but the means are laboreintensive and require controlled crosses. In this paper, we tried to get around these difficulties by working with a natural system comprised of the coexisting sexually reproducing lizard Darevskia portschinskii, and its daughter parthenogenetic form, Darevskia dahli. The excess of individual and between-population variation in the sexual form relative to the parthenogen was used as a measure of heritability of each of 21 scalation traits and principal components extracted from their analysis. We compared these data with microsatellite genotypes based on the analysis of five variable loci. We showed that D. portschinskii had higher individual and between-population phenotypic diversity than D. dahli. Phenotypic differences between populations of D. portschinskii (but not D. dahli) correlate with both the geographic distances and pairwise fixation indices based on the analysis of the genetic markers. This correlation substantially increased when, instead of the original phenotypic distances, the corrected Qst values are used to assess the heritability of the characters. A similar analysis pattern is recommended for various natural systems with coexisting sexually and asexually reproducing organisms.
Biological Journal of the Linnean Society, 2018
Geometric morphometrics is a better tool to evaluate the variation of shape than 'traditional' mo... more 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 the species divergence pattern. This allowed us to separate species from different clades, but we could not distinguish closely related species within a clade. We hypothesized that three-dimensional (3D) head shape data would be sufficiently discriminative to identify closely related species. To test this hypothesis, we compared head shapes of three closely related species of the 'rudis' clade, Darevskia portschinskii, Darevskia valentini and Darevskia rudis, with the last species treated as two distinct groups (D. r. obscura vs. D. r. rudis), using 3D landmark data. The 3D analysis isolated the species of the 'rudis' clade from each other and even separated individuals from populations that showed a genetic introgression pattern. The analysis showed that D. r. obscura is morphologically as distinct from D. r. rudis as from the other nominal species. For this reason, we suggest elevating the status of D. r. obscura to species level, i.e. Darevskia obscura Lantz & Cyrén, 1936.
Ecology and Evolution, 2018
Until recently, brown trout (Salmo trutta sensu Lato) was considered to be a widespread western E... more Until recently, brown trout (Salmo trutta sensu Lato) was considered to be a widespread western Eurasian fish species with facultative anadromy. Its natural range stretches from West Siberia to the Atlantic and throughout West Asia (Maitland & Linsell, 2006). Simultaneously, the taxonomy of brown trout is controversial. In older treatises (e.g., Sabaneev, 1875), it is separated into purely freshwater forms
Zoology in the Middle East, 2017
The Lebanon Lizard (Phoenicolacerta laevis) occurs on the Levantine coast and scattered populatio... more The Lebanon Lizard (Phoenicolacerta laevis) occurs on the Levantine coast and scattered populations are found in isolated coastal habitats along the southern and southwestern 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 Enguri. The analysis of mitochondrial cytochrome b sequence suggests closeness of this population to the populations in the provinces of Kahramanmaraş, Adana and Içel in southern Turkey, rather than to those in Lebanon and Israel. It is thought that the species was introduced from a Turkish region to Anaklia, which was an important trade location at the eastern Black Sea coast until the late 18 th century. This is the first established location of this species outside the eastern Mediterranean area. Climate and competition with rock lizards of the genus Darevskia are the most likely reasons preventing expansion of the species into the neighboring areas of Western Georgia.
Zoologischer Anzeiger, 2017
The genus Darevskia comprises over 20 species of small-bodied lizards, mainly occurring in the Ca... more 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 was based on 'traditional' analysis of morphology, based on multiple body and head measurements and scalation traits. Later, a molecular phylogeny of the genus rejected some of the proposed topology based on morphological traits. In this paper, we used quantitative morphological data (outline-based shape data) to test phylogenetic similarities, as proposed by these earlier hypotheses. We analyzed the pileus shape and the anal area of more than 200 individuals, representing six species of Darevskia, using outline based elliptic Fourier analysis. The analysis did confirm a clustering of the individuals and species (using UPGMA) from the same mitochondrial DNA clade. Hence, the phylogenetic affinity of the major clades in Darevskia could be identified using both molecular methods and outline analysis, whereas a traditional quantitative morphological analysis could not.
Global Ecology and Biogeography, 2016
Aim Our research attempts to provide an explicit explanation of human-biome interactions during t... more Aim Our 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. Location Worldwide. Methods Using climate, terrain, hydrographic, fossil pollen and plantmacrofossil data we developed a model of the distribution of biomes during climate deteriorations of the last glacial period. Subsequently, we analysed current human genetic diversity, the origins of genetic lineages and Palaeolithic human sites in relation to the inferred biomes. Results Our analyses indicated that: (1) current human Y-DNA diversity, the places of origin of human Y-DNA lineages and the distribution of Palaeolithic human settlements are best explained by distance from savanna and dry woodland during a series of glacial maxima, and (2) during periods of relatively benign climate conditions, humans dispersed through areas of high primary productivity while avoiding dense forest cover. Main conclusions In a metapopulation of Palaeolithic humans, the biome of savanna and dry woodland supported source populations and other biomes acted as sinks. Present-day genetic, phenotypical and linguistic differences are largely related to discontinuity of and impeded migration between human source populations during glacial periods, rather than simply geographical distance, and in the post-glacial period there has not been enough time for displacements and admixture of human populations to completely blur these differences.
Biodiversity Data Journal, 2015
Reliable taxonomy underpins communication in all of biology, not least nature conservation and su... more Reliable taxonomy underpins communication in all of biology, not least nature conservation and sustainable use of ecosystem resources. The flexibility of taxonomic interpretations, however, presents a serious challenge for end-users of taxonomic concepts. Users need standardised and continuously harmonised taxonomic reference systems, as well as high-quality and complete taxonomic data sets, but these are generally lacking for non-specialists. The solution is in dynamic, expertly curated web-based taxonomic tools. The Pan-European Species-directories Infrastructure (PESI) worked to solve this key issue by providing a taxonomic e-infrastructure for Europe. It strengthened the relevant social (expertise) and information (standards, data and technical) capacities of five major community networks on taxonomic indexing in Europe, which is essential for proper biodiversity assessment and monitoring activities. The key objectives of PESI were: 1) standardisation in taxonomic reference syst...
Amphibia-Reptilia, 2015
The Caucasian rock lizard Darevskia mixta was sampled and studied from throughout its range, usin... more 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 Greater Caucasus commonly have an unpaired preanal scale, whereas the lizards from the Lesser Caucasus have an additional scale behind the central temporal and subdivided interparietal scale more commonly than those from the Greater Caucasus. The Lesser Caucasus populations are further subdivided into two geographically distinct matrilineages, and are more diverse genetically and morphologically than the Greater Caucasus populations. The central part of the Lesser Caucasus is suggested to be the ancestral area for the entire D. mixta lineage. Successive Pleistocene periods of glaciation appear to be responsible both for the isolation of D. mi...
The region of Javakheti in southern Georgia, at the border with Armenia and Turkey, belongs admin... more The region of Javakheti in southern Georgia, at the border with Armenia and Turkey, belongs administratively to the province of Samtckhe-Javakheti and covers two administrative districts: Ninotsminda and Akhalkalaki (Map 1, Map 2). The entire area of the region comprises 2589 km² (ca. 3.8 % of the country‟s area), the entire population – 102,400 persons (1.9 % of the county‟s population)[The entire statistical data presented here was obtained within the framework of the present project. Other existing statistical sources (TM, 1994; Guretski, 1998) were used in order to adjust some important figures, including the total area of the district and population size]. The region lies in treeless mountain plateau with an average elevation ca. 2000 m, which represents the northern edge of volcanic uplands spreading through the western Armenia, eastern and central Turkey and southern Georgia. From the north, the region borders Borjomi district; from the west – Aspindza district; from the east – Tsalka and Dmanisi districts of Georgia; from the south, the region borders Turkey and Armenia. Javakheti has 99 settlements – villages and two towns – with population size varying between 80 and 15,000. The largest town (and an unofficial centre) is town Akhalkalaki (15,000) in its central part, in valley of the river Paravani. The region has over 100 natural lakes, mostly of volcanic origin, six of that have surface exceeding 5 km².
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Papers by David Tarkhnishvili