Karyotype and sex chromosome differentiation in twoNalassusspecies (Coleoptera, Tenebrionidae).
Cytogenetic features ofNalassus bozdagusNabozhenko & Keskin, 2010 andNalassus plebejusKüster, 1850 were analysed using conventional and differential staining. Mitotic and meiotic chromosomal analysis revealed the diploid number as 2n = 20 (9+Xyp) in both species. Besides the general resemblance of twoNalassusMulsant, 1854 karyotypes, important differences related to variations in the number of metacentric/submetacentric chromosomes, localization of highly impregnated regions which are considered as NOR and heterochromatin distribution are clearly observed. The most prominent difference between two species is found related to the X chromosome which is clearly larger inNalassus bozdagusand has a conspicuous secondary constriction on the long arm. As a result of silver staining, the existence of highly impregnated areas associated with XypofNalassus bozdagusin both prophase I and metaphase I, suggests that NORs are seemingly located on sex chromosomes. On the other hand, the potential NORs ofNalassus plebejuswere observed only in prophase I nuclei. With the application of fluorescence dye DAPI, the AT rich chromosome regions and Xypwhich forms the parachute configuration were shown in both species.
Ege University, Faculty of Science, Department of Zoology, Section of Biology, Bornova, Izmir 35100 TURKEY.
Dirim
D
Şendoğan
Ege University, Faculty of Science, Department of Zoology, Section of Biology, Bornova, Izmir 35100 TURKEY.
Nurşen
N
Alpagut-Keskin
DAPI; Helopini; Karyotype; NOR; Nalassus bozdagus; Nalassus plebejus; Tenebrionidae; heterochromatin; sex chromosomes