Atilla Arslan

Karyotypes of the mammals of Turkey and neighbouring regions: a review

Abstract. Available data on karyotypes of the mammals from Turkey and neighbouring regions (the Balkans, the Caucasus, and the Middle East) were summarized and reviewed in respect of their implications to taxonomy and systematics. In this review, previously unpublished data are presented in 20 species. Terrestrial mammals were taken into consideration, both the native and introduced. Altogether, 156 species occurring in the region concerned were included. The karyotype was studied in 109 of these species in Turkey, in most other species data are available from other geographic regions, and only three species remain unstudied cytogenetically. Intraspecific chromosomal variation (polymorphism or polytypy) was reported in 22 species. A karyotype different from the findings made in other regions was reported in Turkish populations of 17 species. Possible future directions of the cytogenetic investigations of mammals in the region are proposed.

Mitochondrial divergence between three cytotypes of the Anatolian Mole Rat, Nannospalax xanthodon (Nordmann, 1840)

Abstract The Blind Mole Rats of Anatolia (Nannospalax xanthodon (Nordmann, 1840)) are characterised by prolific chromosomal diversification. While the geographic distribution of various cytotypes is well documented, opinions on their taxonomic ranking varies amongst authorities. A partial sequence (630 bp) of mitochondrial cytochrome b gene in 13 Blind Mole Rats from the Konya basin, central Anatolia, which represented three distinct cytotypes (2n=40, 58, and 60) yielded nine cyt b haplotypes. Phylogenetic reconstructions recognized three well supported lineages which matched diploid number counts. Genetic divergences between cytotypes were high (K2P between 8.16% ± 1.19 and 11.33% ± 1.42) and application of the 2% divergence rate to the net divergence estimates suggests their divergence about 3.84 and 5.43 Mya (95% confidence interval=1.53–8.19 Mya). If one would rely on genetic operational criteria in species delimitation, there would be little doubt that the three Nannospalax cytotypes analysed in this study belong to distinct allopatric species. Before translating the results into formal taxonomy, more genetic information should be acquired on different Nannospalax cytotypes occupying the eastern Mediterranean.

The banded karyotype of the 2n = 58 chromosomal race of mole rats from Erzincan, Turkey

Abstract. In this study, the 2n = 58 chromosomal race of blind mole rats, Nannospalax xanthodon, from the Erzincan province in Turkey was investigated. Conventional chromosome staining, Ag-NOR staining and C-banding analysis were carried out in the specimens studied. The karyotype included three small or medium-sized meta/submetacentric pairs and twenty-five acrocentric pairs of autosomes of gradually diminishing size (NFa = 62). C-heterochromatin regions were found in centromeric and pericentromeric areas or in short arms of some bi-armed autosomal pairs and in pericentromeric areas of a few acrocentric autosomes. The X chromosome had a centromeric C-positive band and the short arm of the Y chromosome appeared to be C-positively stained. The NORs were localized in distal heterochromatin areas of the short arms of two pairs of biarmed and one pair of acrocentric autosomes. Within the 58 chromosome populations reported from Turkey, two groups can be recognized differing by the presence or absence of a large submetacentric autosomal pair. The populations possessing this marker chromosome occur in central and northern Anatolia, whereas populations form eastern Anatolia have no similar chromosome in their karyotype.

Chromosomal variation in social voles: a Robertsonian fusion in Günther’s vole

The study reports on chromosomes in several populations of social voles from south-eastern Europe and the Middle East. The standard karyotypes of individuals of Microtus hartingi and Microtus guentheri originating from both south-eastern Europe and Asia Minor comprised 54 mostly acrocentric chromosomes. However, variation between populations was found in the amount and distribution of C-heterochromatin in certain autosomes and the sex chromosomes. Furthermore, a specific pattern of argyrophilic nucleolar organizer region distribution was recorded in different geographic populations. In a population from Asia Minor, a heterozygous centric fusion of two autosomes was found. The G-banded karyotypes of M. guentheri and Microtus socialis were compared, and tandem fusions of autosomes were suggested as possible mechanism of the divergence. The karyotypes of the nine currently recognized species of social voles are reviewed, and implications of chromosomal data for systematics are evaluated.

The chromosome banding pattern in two cytotypes (2n = 36 and 38) of blind mole rats from Turkey (Mammalia: Spalaxidae)

Two cytotypes (2n = 36 and 38) of blind mole rats, Nannospalax xanthodon (Nordmann, 1840), from the Aydın and Manisa provinces in Turkey were investigated. Conventional chromosome staining, Ag-NOR staining and C-banding analysis were carried out. From the cytogenetic point of view, the particular phylogenetic position of these populations is supported by their low diploid numbers only, and the Cbanding pattern and the NORs distribution seem generally similar to populations with higher chromosome numbers. Several autosomal pairs with centromeric dark Cbands were observed in the 2n=36 cytotype. One autosomal pair possessed an interstitial dark C-band on the short arm; another pair possessed an interstitial dark Cband on the long arm. Whole C-heterochromatic short arms were observed in three subtelocentric autosomal pairs in the 2n=38 cytotype. Most of the other autosomal pairs possessed centromeric dark C-bands. Distinct dark C-bands were observed also in the presumed X chromosomes of both the cytotypes. The Ag-NOR regions were found on three autosomal pairs of both the cytotypes. These sites were located in telomeric areas of the short arms of two subtelocentric and one submetacentric pair.

Comparison of the chromosome banding pattern in the 2n = 56 cytotypes of Nannospalax leucodon and N. xanthodon from Turkey.

We present the karyotype characteristics of five cytotypes of mole rats (Nannospalax) with 56 chromosomes revealed by the C-banding and AgNOR staining analyses. We attempt to investigate if the specific distinction between the populations from Thrace (N. leucodon) and Anatolia (N. xanthodon) is reflected also in their karyotypic differentiation. The specimens from each of the five populations studied revealed a distinct karyotype which was different from those found in other populations. The fundamental number of autosomal arms varied from 68 to 72. The amount of C-heterochromatin was larger in the Thrace sample of N. leucodon compared to the Anatolian population of N. xanthodon. The active NOR sites were recorded on five autosomal pairs in N. leucodon, whereas only three or four pairs bearing NOR were observed in N. xanthodon. Differences between the studied populations were quantified in the analysis of the distribution pattern of the C-positive bands and the AgNOR sites in individual chromosomes which indicated a basal position of the Thrace sample of N. leucodon and its divergence from other studied populations. The karyotypes of the 56-chromosome populations of N. leucodon and N. xanthodon are thus distinctly different.

Heterochromatin distribution and localization of nucleolar organizing regions in the 2n = 52 cytotypes of Nannospalax xanthodon and N. ehrenbergi from Turkey

BackgroundThe blind mole rats (Spalacinae) are fossorial rodents exhibiting exceptionally extensive variation in the karyotype. The taxonomy of this group is not definitively resolved, and the species discrimination is often not clear, even with the use of chromosomal analyses.ResultsWe have studied the karyotype of three populations of blind mole rats (Spalacinae) from Anatolia classified tentatively as Nannospalax xanthodon (Bolu and Içel provinces) and Nannospalax ehrenbergi (Gaziantep province). C-banding and AgNOR staining were used in the cytogenetic analysis. In all populations, the karyotype comprised 52 chromosomes including 8 to 10 bi-armed and 17 to 15 acrocentric autosomal pairs. The centromeric position varied in the sex chromosomes between the populations. The C-positive centromeric bands occurred in most of the bi-armed autosomes and the sex chromosomes and in some of the acrocentric autosomes. The nucleolar organizer regions were localized in three (N. xanthodon) or five (N. ehrenbergi) autosomal pairs.ConclusionsIt is difficult to find particular chromosomal differences between the studied populations which could enable unequivocal species identification. This finding emphasizes the need of taxonomic revision of the species structure within the Nannospalax genus.

A new cytotype (2n=46) of Nannospalax xanthodon from Turkey

A new cytotype was found in a population of mole rats Nannospalax xanthodon from south-eastern Anatolia, Turkey. The karyotype contained 46 chromosomes and 66 autosomal arms (11 biarmed and 11 acrocentric autosomal pairs). The X chromosome was submetacentric and the Y chromosome small subtelocentric. Distinct dark C-bands were observed on all the biarmed chromosomes and on three pairs of acrocentric autosomes. The NORs were detected on the short arms of two subtelocentric pairs of autosomes. The published data indicate considerable chromosomal variation between populations of mole rats in south-eastern Anatolia. The finding of a karyotype with a unique chromosomal number in the karyologically well-studied region of south-eastern Anatolia indicates that the karyotype structuring between mole rat populations may be even more complex than previously realised.

Fossorial morphotype does not make a species in water voles

Abstract Phenetic and ecological plasticity in Arvicola has caused a long-standing dispute over the number of species within the genus, which is currently thought to consist of two aquatic (sapidus, amphibius) and one fossorial species (scherman). We used mitochondrial cytochrome b (cytb) gene sequences to reconstruct phylogenetic relationships between the fossorial and the aquatic water voles from the various regions of their European and Asiatic range. These two types differed morphologically and exhibited allopatric ranges. Our study provided 50 new haplotypes, generating a total dataset of 70 different water vole cytb haplotypes. Phylogenetic reconstructions retrieved two major lineages that were in a sister position to A. sapidus: a fossorial Swiss lineage and a widespread cluster, which contained aquatic and fossorial water voles from Europe and western Siberia. The phylogeographic architecture in water voles is explained by Quaternary climatic dynamics. Our results show that A. scherman in its present scope is not a monophyletic taxon.

Mitochondrial sequences point on a cryptic species in five-toed jerboas, subgenus Paralactaga

Abstract We addressed the species taxonomy of five-toed jerboas (Allactaga, subgenus Paralactaga) in the Middle East by applying molecular markers (cytochrome b and a partial 16S rRNA). The study consisted of 17 specimens from eight localities in the Middle East, representing both species: Allactaga euphratica and Allactaga williamsi. The phylogenetic reconstructions yielded three highly divergent lineages, which failed to conform to the recent taxonomy of Paralactaga. The first lineage (williamsi lineage) encompassed all the samples of A. williamsi from Turkey and Iran and also the specimens of A. euphratica from Lebanon. The haplotypes of A. euphratica were arranged into two lineages, which showed strong geographic associations. One lineage contained samples from Harran in Turkey and from Iran, while all the samples from Syria clustered in another lineage. The pairwise Kimura two-parameter values suggested similar divergences between the three lineages and were within the range reported for a sister species of rodents. Our results point to a cryptic species in A. euphratica and also provide evidence of the expanded range of A. williamsi further south to Lebanon.