Submitted to: Physiological Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 19, 2001
Publication Date: N/A
Interpretive Summary: The Meishan breed of pig has many unique features for reproductive characters. Meishan boars have smaller testes and much higher concentrations of FSH. LH and TSH in their plasma. An initial scan of the porcine genome for regions affecting plasma levels of FSH was conducted on 121 boars. The most significant regions were then followed-up with 315 additional boars. Three significant genomic regions were detected (chromosomes 3, 10, and X) and two additional regions may also affect this trait (chromosomes 8 and 18). An analysis to determine if these same genomic regions also control testes size revealed a highly significant association with the X chromosome and testes size, while no other region approached significance. These findings will help scientists determine genes which are important in regulating FSH levels in boars as well as genes that control testes development.
Technical Abstract: The Chinese Meishan breed of pig is quite unique for many reproductive characters as females reach puberty earlier, ovulate more ova per estrus and have greater uterine capacity while boars have smaller testes and extremely elevated plasma levels of pituitary derived glycoprotein hormones. In an effort to identify the genetic mechanisms controlling the elevated plasma levels of pituitary derived glycoprotein hormones (in particular FSH) and to determine if some of these genetic factors are also responsible for differences in other phenotypes we scanned the entire genome for regions which affected plasma FSH in boars from a Meishan-White Composite (equal contributions of Chester White, Landrace, Large White and Yorkshire) resource population. Initially, the entire genome of 121 boars was scanned for regions which potentially influenced plasma FSH. The most significant genomic regions were further studied in a total of 436 boars. Three genomic regions located on chromosomes 3, 10, and X apparently possess genes which significantly affect FSH level; and two regions provided suggestive evidence for the presence of FSH controlling genes located on chromosomes 8 and 18. Only the region on the X chromosome appeared to affect testes size; however, similar genomic regions have been identified to affect ovulation rate in contemporary females for chromosomes 3, 8, and 10.