QTL Analysis of Teat Number Traits in an F2 Intercross between Landrace and Korean Native Pigs

Abstract

The aim of this study was to identify quantitative trait loci (QTLs) influencing teat number traits in an F2 intercross between Landrace and Korean native pigs (KNP). Three teat number traits (left, right, and total) were measured in 1105 F2 progeny. All experimental animals were genotyped with 173 informative microsatellite markers located throughout the pig genome. We detect that seven chromosomes harbored QTLs for teat number traits: genome regions on SSC1, 3, 7, 8, 10, 11, and 13. Six of fourteen identified QTL reached genome-wide significance. In SSC7, we identified a major QTL affecting total teat number that accounted for 5.6% of the phenotypic variance, which was the highest test statistic (F-ratio = 61.1 under the additive model, nominal P = 1.3×10-14) observed in this study. In this region, QTL for left and right teat number were also detected with genome-wide significance. With exception of the QTL in SSC10, the allele from KNP in all 6 identified QTLs was associated with decreased phenotypic values. In conclusion, our study identified both previously reported and novel QTL affecting teat number traits. These results can play an important role in determining the genetic structure underlying the variation of teat number in pigs.

Keywords

• teat number
• quantitative trait locus
• genome-wide linkage analysis
• landrace and korean native pigs