Aim The aim of this study was to elucidate the phylogeographical pattern of taxa composing the Vipera ursinii complex, for which the taxonomic status and the dating of splitting events have been the subject of much debate. The objectives were to delimit potential refugia and to date splitting events in order to suggest a scenario that explains the diversification of this species complex. Location Western Europe to Central Asia. Methods Sequences of the mitochondrial cytochrome b and NADH dehydrogenase subunit 4 (ND4) genes were analysed for 125 individuals from 46 locations throughout the distribution range of the complex. The phylogeographical structure was investigated using Bayesian and maximum likelihood methods. Molecular dating was performed using three calibration points to estimate the timing of diversification. Results Eighty‐nine haplotypes were observed from the concatenation of the two genes. Phylogenetic inferences supported two main groups, referred to in this study as the ‘ursinii clade’ and the ‘renardi clade’, within which several subclades were identified. Samples from Greece (Vipera ursinii graeca) represented the first split within the V. ursinii complex. In addition, three main periods of diversification were revealed, mainly during the Pleistocene (2.4–2.0 Ma, 1.4 Ma and 1.0–0.6 Ma). Main conclusions The present distribution of the V. ursinii complex seems to have been shaped by Quaternary climatic fluctuations, and the Balkan, Caucasus and Carpathian regions are identified in this study as probable refugia. Our results support a south–north pattern of colonization, in contrast to the north–south colonization previously proposed for this complex. The biogeographical history of the V. ursinii complex corroborates other biogeographical studies that have revealed an east–west disjunction (situated near the Black Sea) within a species complex distributed throughout the Palaearctic region.
The concept of climate variability facilitating adaptive radiation supported by the “Court Jester” hypothesis is disputed by the “Red Queen” one, but the prevalence of one or the other might be scale-dependent. We report on a detailed, comprehensive phylo-geographic study on the ∼4 kb mtDNA sequence in underground blind mole rats of the family Spalacidae (or subfamily Spalacinae) from the East Mediterranean steppes. Our study aimed at testing the presence of periodicities in branching patterns on a constructed phylogenetic tree and at searching for congruence between branching events, tectonic history and paleoclimates. In contrast to the strong support for the majority of the branching events on the tree, the absence of support in a few instances indicates that network-like evolution could exist in spalacids. In our tree, robust support was given, in concordance with paleontological data, for the separation of spalacids from muroid rodents during the first half of the Miocene when open, grass-dominated habitats were established. Marine barriers formed between Anatolia and the Balkans could have facilitated the separation of the lineage “Spalax” from the lineage “Nannospalax” and of the clade “leucodon” from the clade “xanthodon”. The separation of the clade “ehrenbergi” occurred during the late stages of the tectonically induced uplift of the Anatolian high plateaus and mountains, whereas the separation of the clade “vasvarii” took place when the rapidly uplifting Taurus mountain range prevented the Mediterranean rainfalls from reaching the Central Anatolian Plateau. The separation of Spalax antiquus and S. graecus occurred when the southeastern Carpathians were uplifted. Despite the role played by tectonic events, branching events that show periodicity corresponding to 400-kyr and 100-kyr eccentricity bands illuminate the important role of orbital fluctuations on adaptive radiation in spalacids. At the given scale, our results supports the “Court Jester” hypothesis over the “Red Queen” one.
We investigated the recent evolutionary history of the Danube crested newt, Triturus dobrogicus through reconstructions of: (1) the number and position of refugia at the last glacial maximum, (2) the role of major central European rivers in pattern of post‐glacial dispersal, and (3) the present‐day distribution pattern. We analysed sequences of mitochondrial DNA (ND2, 1065 bp) and six microsatellite loci in 363 T. dobrogicus individuals from 58 populations covering the range of the species. Our analyses suggested that T. dobrogicus survived the last glacial maximum in two separate refugia positioned in northwestern Pannonia and in Southern Pannonia from where its range expanded along the Danube and Tisza Rivers. Our findings also confirmed that rivers played an important role in shaping the evolutionary history of amphibian species in Central Europe. We compared the T. dobrogicus range with another lowland amphibian, the fire‐bellied toad Bombina bombina, using species distribution modelling. In line with these models, the isolated mountains inside Pannonia are occupied not by B. bombina, but by its mountain‐dwelling sister‐species B. variegata. However, in contrast to the model, crested newts (including T. dobrogicus) are absent from these mountains. We attribute this biogeographical discrepancy to the positioning of the species’ refugia at the last glacial maximum.
BackgroundStudies on allele length polymorphism designate several glacial refugia for Norway spruce (Picea abies) in the South Carpathian Mountains, but infer only limited expansion from these refugia after the last glaciation. To better understand the genetic dynamics of a South Carpathian spruce lineage, we compared ancient DNA from 10,700 and 11,000-year-old spruce pollen and macrofossils retrieved from Holocene lake sediment in the Retezat Mountains with DNA extracted from extant material from the same site. We used eight primer pairs that amplified short and variable regions of the spruce cpDNA. In addition, from the same lake sediment we obtained a 15,000-years-long pollen accumulation rate (PAR) record for spruce that helped us to infer changes in population size at this site. ResultsWe obtained successful amplifications for Norway spruce from 17 out of 462 pollen grains tested, while the macrofossil material provided 22 DNA sequences. Two fossil sequences were found to be unique to the ancient material. Population genetic statistics showed higher genetic diversity in the ancient individuals compared to the extant ones. Similarly, statistically significant Ks and Kst values showed a considerable level of differentiation between extant and ancient populations at the same loci.Lateglacial and Holocene PAR values suggested that population size of the ancient population was small, in the range of 1/10 or 1/5 of the extant population. PAR analysis also detected two periods of rapid population growths (from ca. 11,100 and 3900 calibrated years before present (cal yr BP)) and three bottlenecks (around 9180, 7200 and 2200 cal yr BP), likely triggered by climatic change and human impact.ConclusionOur results suggest that the paternal lineages observed today in the Retezat Mountains persisted at this site at least since the early Holocene. Combination of the results from the genetic and the PAR analyses furthermore suggests that the higher level of genetic variation found in the ancient populations and the loss of ancient allele types detected in the extant individuals were likely due to the repeated bottlenecks during the Holocene; however our limited sample size did not allow us to exclude sampling effect.This study demonstrates how past population size changes inferred from PAR records can be efficiently used in combination with ancient DNA studies. The joint application of palaeoecological and population genetics analyses proved to be a powerful tool to understand the influence of past population demographic changes on the haplotype diversity and genetic composition of forest tree species.
Microcrustacean taxa in temporary waters are important contributors to aquatic biodiversity on the landscape scale even though much of the diversity at the molecular level is still undiscovered. Cladoceran species other than Daphnia are not frequently targeted in molecular investigations. We used nuclear allozyme polymorphisms as well as DNA sequence variation in mitochondrial 16 S and COI gene regions to reveal patterns of genetic differentiation among populations of a cladoceran species -Moina brachiata -that typically inhabits temporary aquatic habitats. Samples originated from 20 temporary to semi-permanent waterbodies in the Hungarian Great Plain of the Pannonian biogeographic region. We observed strong genetic differentiation in the phylogenetic analyses of the concatenated 16 S and COI genes, based on which M. brachiata was found to represent a complex of four cryptic lineages (A, B, C and D) with, however, one of these (lineage D) detected based on only one individual. Regarding the nuclear markers, diagnostic alleles of the PGM and MDH enzyme loci in complete linkage disequilibrium were observed separating the 'B' lineage from the rest. In addition, indirect evidence was provided by the AAT locus, where the AAT1 allele was found to be potentially diagnostic for lineage 'C'. The three phylogenetically defined lineages ('A', 'B', 'C') could be separated from each other along the first canonical axis of a multivariate analysis of occurrence, and this first axis was strongly correlated with depth and salinity of the ponds. There is a strong association between habitat depth and the occurrence of the 'B' lineage. Our results indicate that habitat depth and associated ecological characteristics driven by differences in hydroperiod likely are responsible for the present distribution of the lineages.
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