Saturday, Am, Genetics 34 Melanocortin 1-receptor (mc1-r) Gene Polymor- Phisms Associated with Chicken E Locus Effect of Selection for Body Weight Gain after Early Feed Restriction on Body Weight and Feed Conversion in Japanese Quail

s of papers 9 Saturday, AM, GENETICS 34 Melanocortin 1-receptor (MC1-R) gene polymorphisms associated with chicken E locus alleles. R. Okimoto*1, A. E. Ellett1, and S. Takeuchi2, 1University of Arkansas, Fayetteville, AR, 2Okayama University, Okayama, Japan. The melanocortin 1-receptor (MC1-R) gene has been associated with E locus phenotypes in chickens and has been mapped to the E30 linkage group of the East Lansing reference population. Variant alleles of the E locus are important for accurate down color sexing and also for the inhibition of unwanted tissue pigmentation in broilers. PAMSA (PCR Amplification of Multiple Specific Alleles) tests for various replacement substitutions found in the published E allele sequences gave unexpected results when tested against known alleles of the E locus. To resolve these issues and gain a better understanding of how replacement substitutions in the MC1-R gene are affecting E locus phenotypes we PCR cloned and sequenced a number of accessions of the e+, eb, wheaten (eWh and ey), and the birchin (ER) alleles. Our results indicate that the published e+ allele is likely to be a wheaten sequence. All 3 new wheaten sequences (New Hampshire Reds, Rhode Island Reds, and Buff Minorca) produced an inferred amino acid sequence that was identical to the publish e+ sequence, but all three of our new e+ sequences (two Red Junglefowl accessions and Welsummer) had a Thr143Ala polymorphism. All E alleles sequenced except for the wheaten alleles have Thr143, indicating that the Ala143 mutation may be associated with restriction of black pigment in the feathers. The 2 recessive eb sequences (Smyth Brown Line and commercial broiler) had the Lys92 mutation associated with extended black in both chickens and mice, but they also had a His215Pro substitution. The Pro215 mutation is a likely candidate to attenuate the Lys92 mutation producing a brown instead of a black female. The Leghorn birchin allele had the Lys92 mutation, but the Fayoumi birchin allele did not. Instead the Fayoumi sequence had a Leu133Gln substitution, indicating that the birchin phenotype has at least two distinct alleles associated with it.