2012 Annual Report 1a.Objectives (from AD-416): Genotype rams to indentify genetic markers that may be used to improve reproductive efficiency of sheep. 1b.Approach (from AD-416): Commercially available 50,000 single-nucleotide polymorphism (50K SNP) chips will be used to screen rams for genetic markers that are associated with traits relevant to the reproductive efficiency of sheep. The 50K SNP-chip data and pedigree data will be used to determine the efficacy of using marker-assisted selection approaches for improving reproductive efficiency of sheep. 3.Progress Report: U. S. Sheep Experiment Station scientists provided Washington State University (WSU) scientists with whole-blood samples from rams and pedigrees for those rams. WSU scientists used 50,000 single-nucleotide polymorphism (50K SNP) chips to screen rams for genetic markers that are associated with traits relevant to the reproductive efficiency of sheep. The 50K SNP-chip data and pedigree data are being analyzed and will be used to determine the efficacy of using marker-assisted selection approaches for improving reproductive efficiency of sheep. This research contributes to Objective 1 of the in-house project, "Evaluate different breeds and crosses as specialized paternal and maternal lines in an extensive western rangeland, terminal crossbreeding system". We should be able to determine whether molecular markers can be used effectively to improve reproductive performance.