The X-chromosome, highly conserved within mammals, has been shown to contain major
quantitative trait loci (QTL) for growth and fat deposition in the pig. We have discovered a
BamHI polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP)
marker that was assigned to the porcine X-chromosome by two-point and multi-point
linkage analysis following genotyping of a three-generation Berkshire by Yorkshire reference
family. The marker was positioned 9 cM telomeric to SW2126 and 15.6 cM centromeric
to SW1943. Sequence flanking the marker was found to have high similarity to
existing database porcine DNA repeat elements. Association analyses of the BamHI marker
for growth and meat quality traits in the reference family revealed significant association
with marbling (P < 0.03), 10th rib back fat (P < 0.09) and total lipid percentage (P < 0.05), as well as with loin eye area (P < 0.04), average glycolytic potential (P < 0.03) and average lactate content (P < 0.04). Further studies are required to determine the X-chromosome functional gene affecting fat deposition and growth in the pig.