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.

• Hee-Bok Park(Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, 63242 Jeju, Republic of Korea)
• Sang-Hyun Han(Educational Science Research Institute, Jeju National University, Jeju, Republic of Korea)
• Chae-Kyoung Yoo(Institute of Agriculture and Life Sciences, Gyeongsang National University, 52828 Jinju, Republic of Korea)
• Jae-Bong Lee(Korea Zoonosis Research Institute, Chonbuk National University, 54531 Iksan, Republic of Korea)
• Sang-Rae Cho(Hanwoo Research Institute, National Institute of Animal Science, RDA, 25340)
• In-Cheol Cho(Subtropical Livestock Research Institute, National Institute of Animal Science, RDA, 63242 Jeju, Republic of Korea) Corresponding author