Karyological study on bighead goby (Neogobius kessleri) from southern part of the Caspian Sea

Karyological characteristics of bighead goby (Neogobius kessleri) in the Caspian Sea were studied by examining ۳۰ metaphase chromosome spreads from the kidney tissue of ۱۰ specimens. The chromosome number of this species was found ۲n=۴۶ and the arm number as NF=۴۶. The prepared karyotype of this species consisted of ۲۳ pairs acro-telocentric (a-t) chromosomes. The chromosomal formula can be stated as ۲n=۴۶ (a-t). Karyological parameters showed that relative length was between ۲.۳۴-۷.۰۴ and length variation range of chromosomes was between ۱.۶۷-۵.۰۱ and total length was ۷۱.۱۶µm. It was found that the best chromosomal spread quality were obtained from intraperitonial injection of ۴۰µg/g colchicine for ۵ hours, hypotonization of samples in%۱ sodium tri-citrate solution in ۴ºC and preparation of spreads on cooled slide with flame technique.