Abstract: Karyological characteristics of two specimens belonging to the superspecies Spalax leucodon (Nordmann, 1840) from two central Anatolian localities, Kayseri and Sivas-Gürün, were studied to provide insight into chromosomal variations. The two subterranean mole rats examined in this study had karyotypes with 2n=60, NF=78 and NFa=74. This karyotype has already been described at two sites in previous studies but given here for two new additional localities for the first time.
Introduction
Two superspecies of the subterranean mole rats, Spalax leucodon (Nordmann, 1840) and S. ehrenbergi (Nehring, 1898) are characteristic to Palaearctic region and have been recorded from Turkey. Recently, these two taxa have been studied intensively as model mammals in terms of chromosomal variations and ecologically mediated chromosomal speciation (Nevo et al., 1994, 1995). Studies on species of Spalax in Palaearctic region revealed about 40 chromosomal forms of which 14 were described in various localities in Asia Minor (Gülkaç & Yüksel, 1999; Yüksel & Gülkaç, 1990, 1992, 2001; Musser & Carleton, 1993; Nevo et al., 1994, 1995; Coşkun, 1996a,b, 1999; Ivanitskaya et al., 1997; Sözen & KIvanç, 1998a, b; Sözen et al., 1999; Gülkaç & Küçükdumlu 1999). Nevo et al. (1995) have pointed out that each chromosomal form must be assigned to separate biological species and that there presumably are about 20 species in Turkey.
So far, 10 karyological forms of S. leucodon with 2n = 36, 38, 40, 50, 52, 54, 56, 58, 60 and 62 and four karyological forms of S. ehrenbergi with 2n = 52, 54, 56 and 58 have been reported from Turkey (Yüksel & Gülkaç, 1992, 2001; Nevo et al., 1994, 1995; Ivanitskaya et al., 1997; Sözen & KIvanç, 1998a, b; Sözen et al., 1999; Gülkaç & Küçükdumlu, 1999; Coşkun, 1999).
The purpose of the present study was to provide further information about karyotypic variation observed in central Anatolian mole rats and to contribute the mapping of geographic distributions of each chromosomal form.
Materials and Methods
This study was conducted on two specimens of S. leucodon collected from two distant localities, Kayseri and Sivas-Gürün, in 1999 (Fig. 1). Animals were trapped alive and brought to laboratory for chromosomal preparations. Chromosome preparations were made on bone marrow according to Ford and Hamerton (1956), and at least 20 metaphase cells were scored for chromosome number.
| Fig. 1: | Map showing the distribution of central Anatolian Spalax leucodon populations with karyotypes of 2n=60 and 62 both in this study and in those given in Table 1. Localities A and B were studied in present work, whereas localities 1-18 were studied by previous workers (see Table 1.). Sampling localities are as follows: A: Kayseri (central) , B: Sivas-Gürün, 1: Denizli; 2: Burdur; 3: Afyon, 4: Kütahya, 5: Ankara, 6: AkŞehir, 7: Konya, 8: Karaman, 9: NevŞehir, KirŞehir, 11: Havza, 12: Kayseri, 13: PinarbaŞi, 14: Sivas, 15: SuŞehri, 16: Arguvan, 17: YazIhan, 18: Malatya. Numbers in italic refer to the diploid numbers (2n) recorded from each site. |
| Fig. 2: | Karyotype of a female Spalax leucodon (2n = 60) from Sivas-Gürün, Turkey. |
| Table 1: | List of the localities from which the Spalax leucodon samples with karyotypes of 2n=60 and 62, have been recorded in central Anatolia (additionally 2n = 40-58) |
The karyotype slides have been kept at Department of Biology, Faculty of Arts and Sciences, Erciyes University, Kayseri.
Results
The karyotypes of two female specimens, one from central Kayseri (38° 43' N, 35° 29' E) and the other from Incesu village in Sivas-Gürün (38° 46' N, 37° 7' E) were subjected to chromosomal analyses. Both individuals had the same karyotypes with 2n = 60, NF = 78 and NFa = 74. The karyotypes consisted of 21 pairs of acrocentric and 8 pairs of subtelocentric. The X chromosome was also large submetacentric (Fig. 2).
Discussion
As seen in Fig. 1, the major karyotypes of blind mole rat populations in central Anatolia have been found to be ranging from 2n=60 to 62. However, the other karyotypes (i.e. 2n=40-58) are also known to occur in this region (Table 1). Subsequent studies reported that the karyotype (i.e. 2n = 60) for the mole rat populations from Malatya, YazIhan, Arguvan, KIrŞehir, NevŞehir, Kayseri, Denizli, PInarbaŞI; Ankara, Afyon, Burdur and Akşehir (Nevo et al., 1994, 1995; Ivanitskaya et al., 1997; Sözen et al., 1999; Yüksel and Gülkaç, 2001). However, the karyotype with 2n = 62 was found only in the populations from Kütahya, Afyon, Konya, Sivas, Ankara, Kayseri, Havza and Suşehri (Nevo et al., 1994, 1995) (Fig. 1). The karyotypes (2n=60) given for specimens from Kayseri and Sivas-Gürün in this study are similar to those reported for mole rat populations from Malatya, YazIhan, Arguan, KIrŞehir, NevŞehir, Kayseri, Denizli, PInarbaŞI, Ankara, Afyon, Burdur and AkŞehir in diploid chromosome number but differ in chromosomal arm size and the chromosome morphology (Nevo et al., 1994, 1995; Sözen et al., 1999; Yüksel and Gülkaç, 2001). On the other hand, exactly the same karyotype (i.e. 2n = 60, NF = 78 and NFa = 74) was given for S. leucodon samples from Malatya populations (Nevo et al., 1994, 1995; Ivanitskaya et al., 1997). Sivas-Gürün is reported here for the first time to be occupied by S. leucodon populations with karyotypes of 2n = 60, NF = 78 and NFa = 74. By combining our data with that of Nevo et al. (1995) we were able to confirm that mole rat populations possessing 2n=60 and 62 are apparently two major karyotypic forms in the central Anatolia.