Research on Qualitative Genes of Poultry in the United States Part I

Abstract

SummaryRecent and current research was reviewed for several locations in the United States on qualitative genes of poultry. Some of this research is conducted cooperatively in Regional Research projects NE—60, NC—89 and S—93.Historically, qualitative genes have provided the bases for establishment of different varieties of poultry. These include plumage colour (blue, Bl; dominant white, I; recessive white, c; and silver; S), plumage pattern (extended black, E; dominant wheaten, ewh; brown eb; buttercup, ebc; recessive wheaten, ey; and Columbian restriction, Co), feather pattern (autosomal barring, Ab; lacing, Lg; mottling, mo; penciling, Pg; sex-linked barring, B; and spangling, Sp), plumage distribution (naked neck, Na), feather structure (frizzling, F; hen feathering, Hf; and silkiness, h), feather length (crest, cr; muffs and beard, Mb; and vulture hocks, v), skeletal variation (creeper, Cp; Polydactyly, Po; and dominant rumplessness, Rp), and comb type (pea comb, P; rose comb, R; and duplex comb, D).Most of the qualitative genes which have been identified have had deleterious effects when considered in terms of survival value, fitness, or economical production of poultry meat and eggs. Examples include numerous lethal genes, rose comb, some B blood-group alleles, genetic muscular dystrophy (am), scaleless (sc), sleepy-eye (se), perosis (pe), and extremely slow-feathering (Kn).Several qualitative genes have proved to be economically beneficial. For example, sex-linked barring (B) formerly was used widely to determine sex at hatching time, slow feathering (K) is now widely used for the same purpose, and recessive white (c) eliminates dark pinfeathers in meat-type varieties.Other qualitative genes have the potential for economic significance. Blue eggs (O) may have better shell quality; crest (Cr) may contribute to docility and better production; scaleless (sc) may reduce processing waste; and rumplessness (Rp), wingless (Wg), and naked neck (Na) may increase meat yield and processing efficiency.Still other qualitative genes have been identified which appear to have no significant plus or minus value to the species. Many blood-group alleles, many plumage colour genes in egg-producing varieties, several hemoglobin components, and certain gamma globulin specificities fall in this category. Further research is needed to determine the significance of many of these inherited variations.Increased knowledge of the basic genetics of poultry resulting from the research discussed in this report provide a valuable store of information for future use and application.