Genetics, Vol 147, 1863-1872, Copyright © 1997


INVESTIGATIONS

Nucleotide Sequence Evolution at the {kappa}-Casein Locus: Evidence for Positive Selection Within the Family Bovidae

T. J. Ward, R. L. Honeycutt and J. N. Derr
Department of Veterinary Pathobiology, Texas A {complex} M University, College Station, Texas 77843-4467

{kappa}-Casein is a mammalian milk protein involved in a number of important physiological processes. In the gut, the ingested protein is split into an insoluble peptide (para {kappa}-casein) and a soluble hydrophilic glycopeptide (caseinomacropeptide). Caseinomacropeptide is responsible for increased efficiency of digestion, prevention of neonate hypersensitivity to ingested proteins, and inhibition of gastric pathogens. Variation within this peptide has significant effects associated with important traits such as milk production. The nucleotide sequences for regions of {kappa}-casein exon and intron four were determined for representatives of the artiodactyl family Bovidae. The pattern of nucleotide substitution in {kappa}-casein sequences for distantly related bovid taxa demonstrates that positive selection has accelerated their divergence at the amino acid sequence level. This selection has differentially influenced the molecular evolution of the two {kappa}-casein split peptides and is focused within a 34-codon region of caseinomacropeptide.


This article has been cited by other articles:


Home page
J DAIRY SCIHome page
E.-M. Prinzenberg, K. Gutscher, S. Chessa, A. Caroli, and G. Erhardt
Caprine {kappa}-Casein (CSN3) Polymorphism: New Developments in Molecular Knowledge
J Dairy Sci, April 1, 2005; 88(4): 1490 - 1498.
[Abstract] [Full Text] [PDF]


Home page
J DAIRY SCIHome page
M. H. Yahyaoui, A. Angiolillo, F. Pilla, A. Sanchez, and J. M. Folch
Characterization and Genotyping of the Caprine {kappa}-Casein Variants
J Dairy Sci, August 1, 2003; 86(8): 2715 - 2720.
[Abstract] [Full Text] [PDF]