Cytogenetic analyses of wild sheep populations in northern Iran.

Abstract

Seven populations of wild sheep (<i>Ovis ammon</i>) were studied in northern Iran. Analysis of 34 individuals demonstrated that the eastern populations possess a 2n = 58, including 1 pair of metacentric and 27 pairs of acrocentric autosomes. The 2n for the three western localities is 54, characterized by 3 pairs of metacentric and 23 pairs of acrocentric autosomes. In two intermediate localities animals with the following diploid numbers were collected: 2n = 54, identical to western locality animals; 2n = 55, containing five metacentric autosomes; 2n = 56, containing four metacentric autosomes; 2n = 57, with three metacentric autosomes; 2n = 58, identical to the eastern two localities. The X and Y chromosomes are a large acrocentric and a small biarmed chromosome, respectively, in every specimen. The taxonomy of Iranian wild sheep and several evolutionary factors are considered in the light of these chromosomal data. The nonconformity of currently accepted theories on the origins of domestic sheep with the karyological data now available for wild palaearctic and domestic sheep is discussed.