GENETIC VARIATION IN BOVINE HEAT SHOCK PROTEIN 40 GENE IN AFRICAN, ASIAN AND AMERICAN CATTLE BREEDS

Abstract

DnaJ homolog, subfamily A, member 1 (DNAJA] or Hsp40) encodes a heat shock protein which functions as a co-chaperone of the 70 kDa heat shock protein (Hsp70). Recent work linked it to meat tenderness so we investigated molecular genetic diversity of the N- and C-terminal ends in 15 cattle breeds from Africa, Asia, and North America. We sequenceda total of 1,142 bp of bovine Hsp40 gene representing the N-terminal region (619 bp) and C-terminal region (523 bp) in domestic cattle and compared this to the yak C-terminal region (717 bp). Differences between tropical and temperate breeds possibly suggest genetic differences concomitant with population history and genetic diversity among these breeds. The 124 bp insertion found only in yak DNAJA1 gene represents a remarkable difference of potentially significant functional relevance that warrants further investigation. In-silico functional analysis with PANTHER predicted putative deleterious functional impact of c.161 T>A p.V5 4Q. Genetic differences in Hsp40 gene between tropical and temperate breeds of cattle may result from evolutionary forces acting during periods of adaptation following domestication, and may have functional consequences for economic traits like heat tolerance and meat tenderness in cattle.