Casein SNP in Norwegian goats: additive and dominance effects on milk composition and quality

Genetics Selection Evolution

Research

Binyam S Dagnachew¹  Tormod Ådnøy¹  Sigbjørn Lien²  Georg Thaller³ 

[1] Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432, Ås, Norway;Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432, Ås, Norway;Center for Integrative Genetics, Norwegian University of Life Sciences, P.O. Box 5003, N-1432, Ås, Norway;Institute of Animal Breeding and Husbandry, Christian-Albrechts University, 24098, Kiel, Germany;

关键词: Single Nucleotide Polymorphism;    Milk Yield;    Dominance Effect;    Somatic Cell Count;    Milk Production Trait;   

DOI  :  10.1186/1297-9686-43-31

 received in 2010-11-29, accepted in 2011-08-24,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundThe four casein proteins in goat milk are encoded by four closely linked casein loci (CSN1S1, CSN2, CSN1S2 and CSN3) within 250 kb on caprine chromosome 6. A deletion in exon 12 of CSN1S1, so far reported only in Norwegian goats, has been found at high frequency (0.73). Such a high frequency is difficult to explain because the national breeding goal selects against the variant's effect.MethodsIn this study, 575 goats were genotyped for 38 Single Nucleotide Polymorphisms (SNP) located within the four casein genes. Milk production records of these goats were obtained from the Norwegian Dairy Goat Control. Test-day mixed models with additive and dominance fixed effects of single SNP were fitted in a model including polygenic effects.ResultsSignificant additive effects of single SNP within CSN1S1 and CSN3 were found for fat % and protein %, milk yield and milk taste. The allele with the deletion showed additive and dominance effects on protein % and fat %, and overdominance effects on milk quantity (kg) and lactose %. At its current frequency, the observed dominance (overdominance) effects of the deletion allele reduced its substitution effect (and additive genetic variance available for selection) in the population substantially.ConclusionsThe selection pressure of conventional breeding on the allele with the deletion is limited due to the observed dominance (overdominance) effects. Inclusion of molecular information in the national breeding scheme will reduce the frequency of this deletion in the population.

【 授权许可】

CC BY   
© Dagnachew et al; licensee BioMed Central Ltd. 2011