Unveiling genomic regions that distinguish the Assaf sheep breed from its parental Awassi breed.. Assaf and Awassi sheep breeds.

The local Awassi, a hardy fat-tailed sheep breed, native to the Middle East, has been kept in Israel under extensive conditions. Intensifying sheep production in the last century has been facilitated by crossing the Awassi with the European East Frisian breed, creating the Assaf dairy breed. Further introgression of the B (Booroola) allele of the FecB locus into the Assaf breed improved its prolificacy. Today, the Assaf and the Awassi differ in morphological traits the like tail and horn sizes, coat pigmentation and wool characteristics, as well as, in physiological traits like prolificacy and seasonality. To identify candidate genes associated with creation of the Assaf breed and to reveal non-synonymous mutations in these genes, we deep sequenced Awassi and Assaf individuals along with performing a genome-wide association study (GWAS) to compare allele frequencies in these breeds.