PHYSIOLOGICAL AND MOLECULAR CHARACTERIZATION OF SOME EGYPTIAN SHEEP BREEDS Journal Kayali 1 I. M., M. A. Rashed 1 , M. R. Anous 2 , M. A. A. Sallam 1 And A. H. Atta 1 J. Biol. Chem. Environ. Sci., 2014, Vol. 9 (1): 121-140 www.acepsag.org 1. Dept. of Genetics, 2. Dept of Animal Production, Fac of Agric. Ain Shams University,cairo,Egypt. ABSTRACT Five sheep breeds (Ossimi, Rahmani, Barki, Awassi and Finnish) were used to Physiological screening which revealed that the parameters for fresh semen evaluation were higher in the Ossimi and Finnish rams and low in the Barki and Awassi rams, while Rahmani rams had moderate values. Biochemical analysis for blood plasma proteins succeeded in distinguishing among the tested rams and detecting genetic variation within each breed, but it was not enough to determine the fertility among the rams. While, seminal plasma proteins pattern succeeded to detecting some positive and negative markers to recognized high and low fertility rams of studied breeds. Acr gene, exon5 isolated from sheep rams by two specific primers, according to acrosin gene sequence (Acr) of Ovis canadensis sheep breed. Obtained sequences for Acr gene, exon 5 in the five sheep breeds were compared with each other using BioEdit program. Sequences in Awassi, Barki and Rahmani breeds were identity and were different in Ossimi and Finnish breeds. Eight different nucleotides presented in Finnish breed, while there were five different nucleotides in Ossimi breed. This difference may play important roles in fertility of these rams where Finnish breed have the highest fertility rate. The highest similarity values (1.00) were among Awassi, Barki, and Rahmani breeds, followed by Finnish and Ossimi breeds. While the lowest values (0.98) were between each of Awassi, Barki or Rahmani breeds with Finnish or Ossimi breeds. However, Finnish and Ossimi were closer to each other which in agreement with the semen evaluation. Key words: Rams, Semen, Fertility, Acrosome, PCR, Sequence.