Mapping and polymorphism of bovine ghreline gene

Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic
glands of the abomasum. It is an endogenous growth hormone secretagogue.
Total mRNA was extracted from abomasum and complete ghrelin mRNA was
sequenced by rapid amplification of cDNA ends. The gene contains five exons
and four introns with a short noncoding first exon of 17 bp similar to mouse and
human ghrelin gene. Using a radiation hybrid panel, the gene was mapped to
chromosome 22 near microsatellite markers UWCA49, BM4102, BMS1932,
BM2613 and URB035 with good LOD Score. Some studies detected different
QTLs near these markers like for milk fat percent, milk protein percent and
somatic cell score. So, it would be interesting to study the polymorphism on
the bovine ghrelin gene. Screening for polymorphisms in the five exons and the
introns II and IV on ten Belgian Blue bulls, ten Holsteins bulls and ten
Limousin bulls revealed a total of three single nucleotide polymorphisms. In
order to evaluate if ghrelin could be involved in genetic variation for milk fat
percent, milk protein percent and somatic cell score an association study
between SNPs on ghrelin gene and these traits could be performed in a major
cattle population.