IntroductionAllactaga williamsi Thomas, 1897 was described

on the basis of a single specimen from Lake Van, andits distribution range extends through Turkey,Caucasia, Iran, and Afghanistan (Çolak et al., 1994;Wilson and Reeder, 2005). In Turkey, Ellerman(1948), Os born (1964), and Kral and Benli (1979)

recorded the species from Erzurum and CentralAnatolia (Konya, Amasya, Kayseri, and Nevşehir).The conventionally stained karyotype of A. williamsiwas described by Çolak et al. (1997b) from Elazığ,Malatya, and Niğde, in Turkey. However, informationon differentially stained chromosomes and thedetailed structure of the karyotype is still lacking for

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Research Article

Turk J Zool34 (2010) 533-537 © TÜBİTAKdoi:10.3906/zoo-0906-48

Banded karyotypes of Allactaga williamsi fromCentral Anatolia

Atilla ARSLAN1,*, Jan ZIMA21Department of Biology, Faculty of Science, Selçuk University, 42031 Konya - TURKEY

2Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, 603 65 Brno - CZECH REPUBLIC

Received: 29.06.2009

Abstract: A chromosomal study of 2 populations of Allactaga williamsi from Konya province in Central Anatolia, Turkey,was performed. The diploid number of 48 chromosomes was found in all of the 5 specimens examined. All of thechromosomes except the Y were biarmed and could be identified by unique G-banding patterns. The C-banding analysisrevealed a considerable amount of constitutive heterochromatin in all chromosomes. The C-band positive regions weredistributed mainly in centromeric areas, whereas the Y chromosome stained uniformly and C-negatively. The activeNORs were localized in 2 pairs of small metacentric and submetacentric autosomes. The species of the genus Allactagaare apparently conservative in their karyotypic structure.

Key words: Jerboa, comparative cytogenetics, G- and C-banding, AgNOR staining

Orta Anadolu’daki Allactaga williamsi’nin bantlı karyotipleri

Özet: Orta Anadolu’daki Konya bölgesinden 2 Allactaga williamsi populasyonunun kromozomal çalışması yapıldı.Çalışılan 5 örneğin tamamında diploid kromozom sayısı 48 olarak bulundu. Y hariç kromozomların tamamı iki kolluyduve G-bantlı örnekler ile de tanımlandı. C-bantlama analizi konstitutif heterokromatinin bütün kromozomlarda önemlimiktarda olduğunu gösterdi. C-bantlı pozitif bölgeler başlıca sentromerik bölgelerde dağılmıştı, ancak Y kromozom tektip boyandı ve C-negatifti. Aktif NOR’lar küçük 2 çift metasentrik ve submetasentrik otozomlarda lokalize olmuşlardır.Allactaga cinsini türleri karyotip yapıları içinde açıkça korunuyor.

Anahtar sözcükler: Çöl faresi, karşılaştırmalı sitogenetik, G- ve C-bantlama, Ag-NOR boyama

* E-mail: aarslan@selcuk.edu.tr

this species. The aim of this study was to perform achromosomal banding analysis of the karyotype ofA. williamsi with the use of G- and C-banding andAg-NOR staining to facilitate further comparativecytogenetic studies among jerboas.

Materials and methodsThe animals studied (5 males) were collected from

Konya Province (Gölyazı, Cihanbeyli, 38°33´N,33°11´E, and Çumra, 37°39´N, 32°46´E) (Figure 1).Karyotype preparations were obtained from the bonemarrow of animals treated with colchicine (Ford andHamerton, 1956). After preparation of chromosomeslides, conventional Giemsa-staining was carried out.G-banding was performed following the techniquedetermined by Seabright (1971). Constitutiveheterochromatin and nucleolus organizer regions(NORs) were detected in individual autosomal andsex chromosome pairs via C-banding (Sumner, 1972)and Ag-NOR staining (Howell and Black, 1980),respectively. From each specimen, 10-20 slides wereprepared, and at least 20 well-spread metaphase plateswere analyzed. Chromosome morphologies weredetermined after calculating centromeric indexes.Standard voucher specimens (skins and skulls) weredeposited in the Department of Biology, Faculty ofScience, Selçuk University, Konya, Turkey.

ResultsThe karyotype of A. williamsi consists of 48

chromosomes, including 6 metacentric pairs(numbers 1-6 in Figure 2), 12 submetacentric pairs(numbers 7-18), and 5 subtelocentric pairs (numbers19-23) of autosomes (NFa = 92). The largestmetacentric autosomal pair was distinctly bigger thanthe other 5 pairs of the same morphological group.The largest submetacentric autosomal pair was thedistinctly biggest element of the complement.Secondary constrictions were observed in the longarms of autosomal pair numbers 4 and 7. The Xchromosome was medium-sized and submetacentric,and the Y chromosome was small and acrocentric(NF = 96). All of the autosomes and both of the sexchromosomes could be reliably identified on the basisof their unique G-banding patterns (Figure 3).

The C-banded karyotype of A. williamsi isillustrated in Figure 4. All of the autosomes possesseddistinct C-positive bands. The C-positive regions wereusually extensive and included relatively largepericentromeric areas, except for pair numbers 3, 4,14, 16, and 18, which revealed only weak centromericC-positive bands. The size of the C-positive region onpair number 12 was heteromorphic. The Xchromosome had a centromeric C-positive band andthe Y chromosome appeared to be uniformly and C-negatively stained.

Banded karyotypes of Allactaga williamsi from Central Anatolia

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30 4540

40

35

35300 km 300 km

Gölyazı

Çumra

N

0

Figure 1. Collection localities of Allactaga williamsi in Konya. Cihanbeyli (Gölyazı), 3♂♂ (38°33´N, 33°11´E) and Çumra, 2 ♀♀ (37°35´N, 32°45´E).

By using silver-nitrate staining, NORs werelocalized in the secondary constrictions in the longarms of metacentric pair number 4 andsubmetacentric pair number 17. All of the observedNORs were homomorphic and medium-sized(Figures 2 and 5). The number of active NORs rangedfrom 2 to 4 per cell with an average of 3.3 (n = 20).

DiscussionKaryotypes of the specimens studied were

compared with those reported for Allactaga williamsi,A. euphratica, A. tetradactyla, A. elater, A. major, A.sibirica, and A. jaculus (Vorontsov and Malygina,1973; Zima and Kral, 1984; Çolak et al., 1997a, 1997b;Çolak and Yiğit, 1998; Shahin and Ata, 2001, 2004;

A. ARSLAN, J. ZIMA

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1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22 23 XY

1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22 23 XY

Figure 2. Metaphase spread and karyotype of Allactaga williamsi from Konya, Turkey.Arrows indicate the position of secondary constrictions.

Figure 3. Metaphase spread and G-banded karyotype of Allactaga williamsi fromKonya, Turkey.

Ata and Shahin, 2006; Sözen et al., 2008). It seems thatthe genus is chromosomally rather conservative as nokaryotypic difference can be detected among thespecies studied so far. Most of the published dataconcern conventionally stained chromosomes only,and it is possible that detailed comparisons ofdifferentially stained karyotypes will reveal somevariation. According to Shahin and Ata (2004) andAta and Shahin (2006), only a part of thechromosomes of A. tetradactyla showed distinct C-

positive bands, and dark C-staining was not observedin certain autosomes and the X chromosome. Inrelation to our data in A. williamsi, this difference mayindicate a possible variation in the amount anddistribution of C-heterochromatin among the speciesof the genus Allactaga. A more detailed molecularanalysis using cytochrome b sequence mappingtechnology will be needed to determine the patternsof genome variation or conservation in the genusAllactaga.

Banded karyotypes of Allactaga williamsi from Central Anatolia

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1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22 23 XY

Figure 4. Metaphase spread and C-banded karyotype of Allactaga williamsi fromKonya, Turkey.

1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22 23 XY

Figure 5. Silver-stained metaphase spread and karyotype of Allactaga williamsi fromKonya, Turkey. Arrows indicate the position of active Ag-NORs.

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