Polymorphisms of the porcine dopamineβ-hydroxylase gene and their relation to reproduction and piglet survivability in an Iberian x Meishan F2 intercross

The goals of this study were to sequence and physically map the porcine dopamine beta-hydroxylase (DBH) gene, as well as to perform an association study between polymorphisms of this gene and the reproductive performance and piglet survivability of F-2 pigs from an Iberian x Meishan cross. The porcine DBH gene was positioned by RH mapping near the telomere of chromosome 1q2.13, close to markers SSC10D08 and SW1301. Sequencing of DBH cDNAs from 10 pigs revealed the existence of six nucleotide polymorphisms, two of which led to non-synonymous amino acid substitutions within exon 3 at positions 463A > G and 616A > G that corresponded to Thr155Ala and Lys206Glu respectively. Three haplotypes segregated in an Iberian x Meishan population: DBHX (A(436)-A(616)), DBHY (A(436)-G(616)) and DBHZ (G(436)-G(616)). The DBH haplotypes significantly affected rectal temperatures 1 h after birth (P = 0.002) and have a suggestive effect on the time to first colostrum intake (P = 0.019) and on birth weight (P = 0.019).