FISH- MAPPING AND STANDARD GTG-BANDING KARYOTYPE OF THREE EGYPTIAN SHEEP BREEDS

Standardized karyotyping by GTG- banding technique and physical chromosome mapping by Fluorescent in Situ Hybridization (FISH) were utilized to characterize the three Egyptian breeds of sheep (Barki, Rahmani and Ossimi). Blood samples were collected from 15 individuals from each breed of sheep. G-banded chromosomes revealed that the karyotype macrostructure was highly conserved and in considerable accordance to the standard karyotype of the Ovis aries. The chromosome diploid number was 54 (2n=54, XX / XY). The karyotype formula was 2n, 54 = Lm6 + Ma22 + Sa24+ sex chromosomes. Physical chromosome mapping of the three breeds (Barki, Rahmani and Ossimi) was carried out by localization of two subtelomeric SSR and two (SPRN) related specific sequences. The two subtelomeric SSR sequences revealed six different loci in five chromosomes (1p37, 1p36 and 17q26 with the EPCDV008 probe) and (2q45, 4q22 and 24q24 with the EPCDV016 probe), respectively. In addition the two (SPRN) related specific sequences were successful in differentiating among the three breeds. The probe OriaBAC273H7 hybridized to a similar locus (20q13) in breeds Rahmani and Ossimi, while, in Barki, it hybridized to a different locus (22q24). However, probe OriaBAC265G4 hybridized to three different loci (17q25, 22q24 and 20q13) in Barki, Rahmani and Ossimi, respectively.