9. Ovine DRB1 Polymorphism and Its Associations with Body Weight, Milk Contents and Immunological Parameters

The DRB1 gene is known as a part of the Major Histocompatibility Complex (MHC) with important effects on disease resistance and immunological response in mammals. Single strand conformational polymorphism (SSCP) analysis and direct DNA sequencing methods were employed to study the second exon of DRB1 gene polymorphism in Mehraban and Lori-Bakhtiari sheep, using 155 Mehraban and 167 Lori-Bakhtiari (totally 322) ewes. Eleven different SSCP patterns with 26 SNPs (five new mutations) were found in both breeds. Associations of different genotypes with some traits including body weight, milk contents, milk somatic cell count and some immunological parameters were also studied. The observed genotypes had significant associations (P