Mapping Quantitative Trait Loci Affecting Female Reproductive Traits on Porcine Chromosome 81

Abstract

An understanding of the genetic control of porcine female reproductive performance would offer the opportunity to utilize natural variation and improve selective breeding programs through marker-assisted selection. The Chinese Meishan is one of the most prolific pig breeds known, farrowing three to five more viable piglets per litter than the European Large White breed. This difference in prolificacy is attributed to the Meishan's superior prenatal survival levels. The present study utilized a three-generation cross in which the founder grandparental animals were purebred Meishan and Large White pigs in a scan for quantitative trait loci (QTL) on porcine chromosome 8 (SSC8) associated with reproductive performance. Reproductive traits, including number of corpora lutea (ovulation rate), teat number, litter size, and prenatal survival, were recorded for as many as 220 F2 females. Putative QTL for the related traits of litter size and prenatal survival were identified at the distal end of the long arm of SSC8. A physiological candidate gene, SPP1, was found to lie within the 95% confidence interval of these QTL. A suggestive QTL for teat number was revealed on the short arm of SSC8. The present study demonstrates, to our knowledge, the first independent confirmation of QTL for fecundity on SSC8, and these QTL regions provide a crucial starting point in the search for the causal genetic variants.

Detection of quantitative trait loci for teat number and female reproductive traits in Meishan × Large White F2 pigs

“…Conversely, the SSC 18 QTL detected using HFS model had the same location and rather similar effects (1.2 piglets born alive v. 1.37 embryos) as that recently detected in French Large White and Landrace pig populations (Tribout et al, 2008). The QTL detected on ES do not correspond to the single previously published QTL on prenatal survival (King et al, 2003). Moreover, no reproduction QTL clearly corresponds to the chromosomal regions where reproduction candidate genes have been detected (Buske et al, 2006).…”

A whole genome scan to detect quantitative trait loci for gestation length and sow maternal ability related traits in a White Duroc × Erhualian F2 resource population

“…According to the porcine QTL database (Hu et al, 2005), QTL influencing ovulation rate (Rathje et al, 1997), TNB and NBA (King et al, 2003) have also been mapped to this chromosome. This further confirms that the pig chromosome 8 plays very important roles to porcine female reproduction.…”

Molecular cloning and polymorphism of the porcine H2AFZ gene

“…Here pH2AFZ gene was predicted to be located to 124.6 cM on the PiGMaP genetic map. Therefore, the pH2AFZ gene remains a reasonable positional candidate gene of the QTL for NBA at 125 cM (King et al, 2003), a linked marker gene of the QTL for uterine capacity at 71 cM (Rohrer et al, 1999), but probably is not a candidate gene of the QTL for ovulation rate and ovary weight at the distal end of the long arm of SSC8. Means within a column without common subscripts differ (P , 0.01).…”

“…There were many quantitative trait loci (QTLs) for reproduction traits on the SSC8q listed in the released Pig QTL Database (http://www.animalgenome.org/cgi-bin/QTLdb/browse, December 28, 2007), including QTLs for litter size at 127 cM and number born alive at 125 cM (King et al, 2003), uterus capacity at 71 cM and ovary weight at 122 cM (Rohrer et al, 1999), age for puberty at 101 to 102 cM (Cassady et al, 2001) and ovulation rate at 107.5 cM (Rathje et al, 1997).…”