Number Of Autosomal Arms Research Articles

Gerbillus dasyurus (Rodentia: Gerbillinae) Record from Hatay Province, in the South of Turkey

Wagner’s gerbil, Gerbillus dasyurus, is present in Middle East, Arabian Peninsula and marginally into eastern desert of Egypt. The only records have been taken from Kilis in Turkey. In the present study, 10 specimens were collected from three localities in the Hatay Province. These specimens were captured in rocky hills and slopes with poor soil and vegetation on blocky igneous rocks, and also in the rocky lava flow area in the north eastern part of the Hatay Province. Diploid number of chromosome, number of chromosomes and fundamental number of autosomal arms of the specimens was found as 2n = 60, NF = 70 and NFa = 66, respectively. The relative abundance of species was estimated to be 2.74. The mean of the entire baculum is 2.37 mm long, and 0.52 mm the maximum wide (n=3). Number of roots on molars: 3 (M1 and M2), 2 (M1 and M2) and, 1 M3 and M3. The tail lenght is markedly longer than the total legnth of head and body. Morphological and karyologic characters of the samples verify that the indivuduals investigated belongs to Gerbillus dasyurus. However, it is possible to show inter- and intrapopulational variations because of the differences seen in the root number of M1, the proportion of the tail, and the shape of baculum etc., through a detailed study that covers all distribution area. This record is the second record of the species from Turkey. Since no examples could be obtained in the later studies in Kilis region, which was the first record locality, the protection of the new record localities in Hatay is important for the survival of the species in Turkey.

Karyotypes and ZZ/ZW Sex Chromosome System of Endemic Squalius recurvirostris (Leuciscinae, Cyprinidae) in Turkey

In this study, detailed cytogenetic properties of the endemic Akşehir chub, Squalius recurvirostris, distributed in the basin of the Ilgın (Çavuşçu) Lake basin was investigated by applying the standard Giemsa staining, C-banding and Ag-NOR technique. Diploid chromosome number is (2n) 50. A pair of heteromorphic chromosomes was detected in the karyotype in females. However, this difference was not observed in males. Therefore, it was determined that the heteromorphic chromosome pair in females were ZZ/ZW sex chromosomes. The Z chromosome in females is large acrocentric, and the W chromosome is medium-sized submeta/subtelocentric. The number of all chromosomal arms (NF) is 90, and the fundamental number of autosomal arms (NFa) is 88 in the karyotyped of the individuals studied. Some bi-armed and acrocentric chromosomes have centromeric C-bands in the chromosome set. The slightly centromeric or pericentromeric C-bands are observed in some chromosomes, while other chromosome pairs are C-negative. In the individuals studied two active NORs were detected. Both of these NORs were hemizygous and associated with a large C-heterochromatin region. One of the NORs was detected on the entire long arm of the submetacentric chromosome pair and the other on the entire short arm of another submetacentric chromosome pair.

Karyotypic Analysis of the Clipper Barb <i>Enteromius callipterus</i> (Boulenger 1907) from Tahoss Stream, Jos Plateau, Nigeria

The chromosomes of male and female individuals of Enteromius callipterus [1] were assessed in this study with the objective of determining the diploid chromosome and karyotype. The samples were obtained from the Tahoss River, Jos Plateau, and the assessment of the chromosomes was conducted using the conventional Giemsa staining technique. The study reveals that the male individual of E. callipterus has a diploid chromosome number of 2n = 50, the fundamental number of autosomal arms (NFa) of 82, and a karyotype formula of 2n = 14M + 4m + 32t. However, none of the spreads obtained for the female individuals were either equal to or below the common diploid chromosome number of 50 known for members of the genus. The two spreads presented here were of 2n equal to 54 and 58. Although sex dimorphism is rare within the genus, the present results suggest E. callipterus show sexual dimorphism at the chromosomal level.

Chromosomal relationships among the native rodents (Cricetidae: Oryzomyini) of the Galápagos Islands, Ecuador

Although the Galápagos Islands are recognized for their contribution to our understanding of evolutionary theory and have received the attention of scientists for over 185 years, our understanding of the native rodents there has been minimal relative to many other groups of organisms. Much of what we knew through most of the 20th century was based solely on species descriptions. Chromosome data has been limited to only Nesoryzomys narboroughi (2n = 32, FN (number of autosomal arms) = 50) and Aegialomys galapagoensis (2n = 56; FN = 58). We present the karyotypes of the only remaining extant species in the genus, N. swarthi (2n = 56; FN = 54) and N. fernandinae (2n = 44; FN = 54). Chromosomal banding reveals that extensive rearrangement has occurred within Nesoryzomys, including Robertsonian fusion and tandem fusion events but these alone cannot account for the diverse diploid numbers found within the genus. We propose that 1) N. swarthi represents the ancestral karyotype for the genus, similar to A. galapagoensis, 2) N. swarthi and N. fernandinae share the same fundamental number, suggesting divergence by Robertsonian fusions, and 3) N. narboroughi has the most derived karyotype, based on banding morphology and low diploid number.

C-Heterochromatin and nucleolus organizer region distribution of Myotis emarginatus (Chiroptera: Vespertilionidae) from Turkey

In this study, the banded karyotypes (C- and Ag-nucleolus organizer regions (NORs)) of Myotis emarginatus in Turkey were determined for the first time. The karyotype contained 44 chromosomes, the number of chromosomal arms (NF) was 54, and the number of autosomal arms (NFa) was 50. Slight C-heterochromatic blocks were observed in the centromeric regions of some autosome pairs, whereas the sex chromosomes were euchromatic. The Ag-NORs were detected in the short arms of a large and a medium-sized acrocentric autosome. The distribution of C-heterochromatin regions in Turkish populations of M. emarginatus is similar to those reported in some other Myotis species.

Genetic Variability of Three Isolated Populations of the Muya Valley Vole Alexandromys mujanensis Orlov et Kovalskaja, 1978 (Rodentia, Arvicolinae)

In the present study, on the basis of cytogenetic and molecular genetic (mtDNA control region) analysis, genetic variability of the Muya valley vole, Alexandromys mujanensis, an endemic of Buryatia and the northwest of Zabaykalsky krai, was assessed. Three isolated valley vole populations from the Muisko-Kuandinskaya and Barguzinskaya depressions, as well as the Baunt Lake valley, were examined. Polymorphism in the number of autosomal arms (NFa = 46–49) with a stable number of chromosomes (2n = 38), determined by morphological variability of four pairs of autosomes (MMUJ2, MMUJ7, MMUJ8, and MMUJ14), rather than two, as previously thought, was revealed. To date, for the Muya valley vole, ten karyotype variants have been identified. It seems likely that chromosomal rearrangements (pericentric inversions, as well as two variants of fusion of acrocentric chromosome pairs, i.e., centromeric-centromeric and centromeric-telomeric), which led to variability in autosome morphology in the populations of the Muya valley vole, are not harmful. Analysis of the mtDNA control region revealed high haplotype and nucleotide diversity for the species as a whole, while in the valley vole samples from the Dzherginsky Nature Reserve (Barguzinskaya Depression) and the Baunt lake valley, nucleotide diversity was reduced compared to the sample from the Muisko-Kuandinskaya Depression. Despite the fact that each of the studied populations has a unique composition of chromosomal rearrangements and mtDNA haplotypes, higher similarity between the populations of the Muisko-Kuandinskaya Depression and the populations of the Baunt lake valley can still be suggested.

Karyotypes of field mice of the genus Apodemus (Mammalia: Rodentia) from China.

Karyotypes of four Chinese species of field mice of the genus Apodemus were examined, including Apodemus chevrieri (diploid chromosome number, 2n=48, fundamental number of autosomal arms, FNa=56), A. draco (2n=48, FNa=48), A. ilex (2n=48, FNa=48), and A. latronum (2n=48, FNa=48). Karyotypes of A. chevrieri, A. draco, and A. ilex are reported here for the first time, providing useful information for their species taxonomy. Determining the karyotypes of all species of Apodemus in Asia, both in this and previous studies, provides a solid overview of the chromosome evolution and species differentiation of the genus in East Asia. In addition to allopatric speciation, chromosome rearrangements likely played an important role in the formation of the four Apodemus species groups as well as speciation within each group in East Asia. For example, increased centromeric heterochromatin in A. latronum may have contributed to the post-mating reproductive isolation from the A. draco-A. ilex-A. semotus clade.

Comparison of the Chromosome Banding Pattern in the2n=56Cytotypes ofNannospalax leucodonandN. xanthodonfrom 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.

A Comparative Study of Meiotic Recombination in Cattle (Bos taurus) and Three Wildebeest Species (Connochaetes gnou, C. taurinus taurinus and C. t. albojubatus)

The karyotypic evolution in the family Bovidae is based on centric fusions of ancestral acrocentric chromosomes. Here, the frequency and distribution of meiotic recombination was analyzed in pachytene spermatocytes from Bos taurus (2n = 60) and 3 wildebeest species (Connochaetes gnou, C. taurinus taurinus and C. t. albojubatus) (2n = 58) using immunofluorescence and fluorescence in situ hybridization. Significant differences in mean numbers of recombination events per cell were observed between B. taurus and members of the genus Connochaetes (47.2 vs. 43.7, p < 0.001). The number of MLH1 foci was significantly correlated with the length of the autosomal synaptonemal complexes. The average interfocus distance was influenced by interference. The male recombination maps of bovine chromosomes 2 and 25 and of their fused homologues in wildebeests were constructed. A significant reduction of recombination in the fused chromosome BTA25 was observed in wildebeests (p = 0.005). This was probably caused by interference acting across the centromere, which was significantly stronger than the intra-arm interference. This comparative meiotic study showed significant differences among the species from the family Bovidae with the same fundamental number of autosomal arms (FN_a = 29) which differ by a single centric fusion.

Karyotypes of the Mole Rats, genus Nannospalax (Palmer, 1903) (Spalacidae: Rodentia) populations in eastern Anatolia, Turkey

The Spalacidae are Southeast European and East Mediterranean blind rodents, highly adapted for life underground. Their taxonomy needs a modern revision including chromosomal data as well as morphology. Mole rats of the family Spalacidae range over Turkey and approximately 30 karyotypes of Nannospalax complex inhabit. The diploid number of chromosome of Nannospalax ranges from 36 to 62. Also, fundamental number of chromosomal arms, NF values vary from 66 to 92 while the fundamental number of autosomal arms, NFa ranging from 62 to 88. Unfortunely, karyological studies of the Nannospalax populations on the territory of Turkey on the whole are far from being satisfactory. Karyological studies of this group may yield further chromosomal forms in Turkey, which has a wide range of climatic and biotic conditions and the boundaries of the distribution region of the known species might be determined. In this study, chromosomal forms of Nannospalax in East Anatolia (Erzurum, Kars and Agri province) were investigated. The materials of 16 specimens of Nannospalax were collected at 8 different localities in the region. Preparations of mitotic chromosomes were obtained from bone marrows by means of the general air-drying technique. Skins and skulls of specimens have been deposited at the Dicle University, Science Faculty Biology Department. We have identified two chromosomal forms of Nannospalax in East Anatolia of which have diploid chromosome numbers (2n) are 2n = 48 and 2n = 50

Phylogeographic Structure and Karyotypic Diversity of the Brazilian Shrew Mouse (Blarinomys breviceps, Sigmodontinae) in the Atlantic Forest

Blarinomys breviceps possesses cryptic and burrowing habits with poorly documented genetics and life history traits. Due to its rarity, only a few specimens and DNA sequences have been deposited in collections worldwide. Here, we present the most comprehensive cytogenetic and molecular characterization of this rare genus. Phylogenetic analyses based on partial cytochrome b sequences were performed, attempting to establish the relationships among individuals with distinct karyotypes along the geographic distribution of the genus in the Atlantic Forest. Classical and molecular cytogenetics, using banding patterns and FISH of telomeric and whole chromosome X-specific painting probes (obtained from the Akodontini Akodon cursor) were used to characterize and compare the chromosomal complements. Molecular phylogenetic analyses recovered 2 main geographically structured clades, northeastern and southeastern with pairwise sequence divergences among specimens varying between 4.9 and 8.4%. Eight distinct karyomorphs are described: (A) 2n = 52 (50A, XX), (B) 2n = 52 (48A, XY+2Bs), (C) 2n = 45 (42A, XY+1B), (D) 2n = 43 (37A, XX+4Bs), (E) 2n = 37 (34A, XY+1B), (F) 2n = 34 (32A, XX), (G) 2n = 31 (27A, XX+2Bs), (H) 2n = 28 (26A, XY), all with the same number of autosomal arms (FN_A = 50). Variation of 0–4 supernumerary chromosomes (Bs) presenting heterogeneity in morphology and distribution of interstitial telomeric sequences (ITSs) is reported. ITSs are also found in some metacentric autosomes. The phylogeographic separation between 2 major lineages with high levels of genetic divergence, and the wide karyotypic diversity indicate that B. breviceps is a diverse group that warrants taxonomic re-evaluation.

A new karyotype for Rhipidomys (Rodentia, Cricetidae) from Southeastern Brazil

In this work we present a new karyotype for Rhipidomys Tschudi, 1845 (Cricetidae, Rodentia) from Brazil. Our chromosome analyses included GTG- and CBG-banding patterns, the localization of the nucleolus organizer regions after silver staining (Ag-NORs) and fluorescence in situ hybridization (FISH) with a telomere probe. The new karyotype is composed of 44 chromosomes and has a fundamental number (number of autosomal arms) of 48. Most Rhipidomys species already karyotyped presented similar complements with 2n=44, but their fundamental numbers varied from FN=46 to 80, a variation that has been mainly attributed to pericentric inversions. The comparison of this new karyotype to those of other Rhipidomys already reported allowed us to conclude that it is a distinctive chromosome complement, which can be of great use as a tool for the very complicated taxonomic identification in this genus.

Nucleolar organizer regions in Mesocricetus brandti (Nehring, 1898) (Mammalia: Rodentia) from the Yozgat and Tokat provinces of Turkey

Mesocricetus brandti possesses a diploid chromosome number of 2n = 42, a fundamental number of NF = 82, and a fundamental number of autosomal arms of NFa = 78. The chromosome set consists of 17 meta-submetacentric pairs, 2 subtelocentric pairs, and 1 acrocentric pair. The X chromosome is large and metacentric while the Y is medium-sized and metacentric. The nucleolar organizer regions were located at the telomeric region of 7 biarmed autosomes and at the centromeric region of 1 acrocentric autosome.

A new karyotype of Wiedomys pyrrhorhinus (Rodentia: Sigmodontinae) from Chapada Diamantina, northeastern Brazil

A new karyotype of Wiedomys pyrrhorhinus (Wied, 1821) is described, including G- and C-banding and Ag-NOR sites from specimens collected in the municipality of Morro do Chapeu, situated in the northern region of the Chapada Diamantina, state of Bahia. Karyological studies of W. pyrrhorhinus have shown a constant diploid number (2n) of 62 with two different numbers of autosomal arms (FNa): 86 and 90, respectively. The new karyotype revealed 2n = 62 and FNa = 104, being the higher autosomal number found so far for this genus. The X chromosome is a large acrocentric and the Y chromosome is a small acrocentric. The analysis of the karyotype morphology suggests that this new karyotype is more closely related to the previous karyotype with 2n = 62 and FNa = 90, described from Caetite, Bahia State. Further studies, comparing different populations of W. pyrrhorhinus, including molecular approaches, may help to better understand the geographical limits of each population and their phylogenetic relationships in the Caatinga biome

Distributional, morphological and karyotypic contributions for the Eurasian water vole, Arvicola amphibius (Linnaeus, 1758) (Rodentia: Mammalia), from Turkey

The present study was focused on both the new distributional records and karyological data for Arvicola amphibius from the European part of Turkey. The karyotype of the Eurasian water vole was investigated by examining its metaphase chromosomes. The diploid number of chromosomes (2n), the fundamental number of chromosomal arms (FN) and the number of autosomal arms (FNa) were found to be 36, 64 and 60, respectively, for one female individual from a single locality in the European part of Turkey. It was determined that A. amphibius has 2n = 36 chromosomes, consisting of seven metacentric, three submetacentric, three subtelocentric and four acrocentric chromosome pairs. The X chromosome was a large submetacentric. The present study confirmed the previous results with regard to 2n. However, comparison of our findings with those of other authors indicates that there are karyotypic differences among the chromosomes. These differences were related to the morphology of chromosomes. Additionally, we reported external and skull measurements and new distributional records from six localities for the Turkish water vole. The measurements presented in this study conform to those of samples examined by other authors.

Karyotypic Variation in Rhinolophid and Hipposiderid Bats (Chiroptera: Rhinolophidae, Hipposideridae)

According to current phylogenetic hypotheses, the bats of the families Rhinolophidae and Hipposideridae are sister groups nested within the clade of Pteropodiformes. A conservative nature of karyotypic evolution was previously reported within the two families. Karyotypes with diploid number (2n) varying between 58 and 62 chromosomes were assumed to prevail among the rhinolophid species, whereas, karyotypes with 32 chromosomes were found in most of the hipposiderid bats. However, divergent lower or higher 2n numbers have been recorded in some species in both families. Variation is documented in the present paper by examination of non-differentially stained karyotypes in 10 species belonging to genera Rhinolophus and Hipposideros from western Africa and southern India. Among the species studied, the karyotypes with a 2n of 32, 36, 52, 56, 58, and 62, and with relatively stable number of autosomal arms (FNa = 60, 62, 64) were recorded.

Chromosome-banding study in Gerbillinae (Rodentia). I. Comparative analysis of Gerbillus poecilops, G. henleyi and G. nanus

An analysis was made of the R- and C-banding of chromosomes of the following Gerbillus species (Rodentia, Gerbillidae): G. poecilops (Taif, Saudi Arabia), G. henleyi (Oursi, Burkina Faso; Kairouan, Tunisia), and G. nanus (Taif and Hofuf, Saudi Arabia; Sind desert, Pakistan). Their karyotypes show the same chromosome number (2n = 52), but a different N.F.a. (number of autosomal arms), ranging from 58 to 62 in the species overall, and from 58 to 60 among G. nanus forms, due to pericentric inversions involving chromosomes 1 and 4. Moreover, large inter-individual variations of heterochromatin segments of chromosomes 25, X, and Y were found. Considering morphology and karyotype, G. poecilops and G. henleyi appear to be rather monomorphous species, whereas G. nanus produces a series of forms as a consequence of speciation, in which both chromosomal and morphological differentiations occur that do not correlate.

Banded karyotypes of mole rats (Spalax, Spalacidae, Rodentia) from Turkey: a comparative analysis

Chromosome banding (G-, C- and Ag-NOR) analysis was carried out on 27 specimens of Sphalax ehrenbergi from seven localities and two specimens of S. leucodon from one locality, all from Turkey. No chromosomal variation was detected in S. ehrenbergi populations from Elazig, Siverek, Diyarbakir and Birecik having the same diploid numbers (2n = 52) and morphology of chromosomes (NFa = 72). The karyotypes of mole rats from Tarsus and Gaziantep possessed the identical diploid number (2n = 56) but different numbers of autosomal arms: NFa = 68 in the Tarsus and NFa = 78 in the Gaziantep populations. Chromosomes of S. leucodon from Malaty (2n = 60, NFa = 74) differed distinctly in the C-banding pattern from all S. ehrenbergi cytotypes by the almost entire absence of heterochromatin in acrocentric autosomes and the presence of heterochromatin arms iin subtelocentric autosomes. Nucleolar organizing regions were found mainly on three pairs of chromosomes, but some differences in their localization were revealed. Comparison of G-banded chromosomes showed, that most chromosomes have a similar pattern. The types of chromosomal rearrangemetns were revealed due to the banding methods.

Macro‐Anatomical and Karyological Features of Two Blind Mole Rat Subspecies (Rodentia: Spalacidae) from Turkey

The morphometric and karyological analyses of 52 specimens belonging to the two subspecies of Nannospalax leucodon were examined from 14 localities in Turkey. Five karyotypic forms were recorded (2n = 60, the total numbers of chromosomal arms (NF) = 74, the numbers of autosomal arms (NFa) = 70; 2n = 60, NF = 76, NFa = 72; 2n = 60, NF = 82, NFa = 78; 2n = 56, NF = 72, NFa = 68; 2n = 38, NF = 74, NFa = 70). The morphological features of two subspecies were studied using both numerical taxonomy and traditional methods. Thirty skull measurements and four baculum measurements were subjected to discriminant function analysis to find morphometric criteria allowing subspecies identification. Two subspecies were clearly separated from each other by macroanatomical characterictics and numeric characteristics. The first upper molar has four alveoli cubicles in young specimens of Nannospalax leucodon anatolicus, while M(1) has 1 cubicle in Nannospalax leucodon cilicicus. In the western subspecies (N. l. anatolicus, 2n = 38), urethra openness is surrounded by three lobes. However, in the eastern subspecies (N. l. cilicicus, 2n = 60), there are two lateral lobes.

Cytogenetic Studies on European Brown Hare, Lepus europaeus Pallas, 1778 (Lagomorpha: Leporidae) in Turkey

Summary In this study, the karyotype, C-heterochromatin blocks, and nucleolar organizer regions (NORs) of four specimens of Lepus europaeus from Turkey were examined. The diploid number of chromosomes (2n), the fundamental number of chromosome arms (FN), and the number of autosomal arms (FNa) were determined as 48, 90, and 86, respectively. All of the chromosomes have been determined to be possessed of centromeric constitutive heterochromatin, except of the pair no. 10. The X chromosome had centromeric heterochromatin and Y chromosome had pericentromeric heterochromatin. There were no distal C-bands in any chromosome of samples. The NORs have been determined to be located in the terminal regions of the long arms of three subtelocentric chromosomes (nos. 15, 16, and 18). Any relation was not determined between the localization of the NORs and C-positive regions of autosomes.