The Blackhead Somali karotype - A new contribution to elucidating the taxonomy of the genus Ovis

DANIELA M FERRÉ; P CUERVO; AAM QUERO; L LLAVER; E YANZON; V HYNES; A PEDROSA; L ALBARRACÍN; NORA B GORLA

Mendoza

Otro; 28° Reunión Científica Anual Sociedad de Biología de Cuyo; 2010

Sociedad de Biología de Cuyo

Among food-producing animals, the genus Ovis is particularly complex with regard to its evolution and systematics, due to morphological and geographic parameters. Blackhead Somali is characterized by its white torso and extremities, as well as the black pigmentation of its head and neck. No reports concerning its karyotype are available in the international bibliography. Usually, Blackhead Somali is classified as the species Ovis aries steatopigas. Recently, however, categorizing Blackhead Somali as Ovis orientalis aries has been suggested. The objective of the present study was to determine the G-band karyotype of the Blackhead Somali, and compare it to the karyotype of the domestic sheep (ISCNDA 1990), thus contributing to elucidating the taxonomy of the genus Ovis, based on cytogenetics. Lymphocyte cultures from a male and a female animal were processed by means of traditional cytogenetic methods in order to obtain metaphases (Buckton and Evans 1973 mod.), and differential G-band stains were obtained (Seabright, 19 71). The animals studied showed 2n= 54 with three large metacentric- submetacentric and 24 telocentric chromosomes, including sexual chromosomes. However, distinguishing between chromosomes 4 and 6 proved difficult. Based on the high similarity between the karyotypes of both, the present study supports the categorization of the Blackhead Somali as a breed of the domestic sheep.