Association of parathyroid hormone-like hormone (PTHLH) and its receptor (PTHR1) with the number of functional and inverted teats in pigs.

Parathyroid hormone-like hormone gene (PTHLH) and its receptor, parathyroid hormone/ parathyroid hormone-like hormone receptor 1 (PTHR1), play a role in epithelial mesenchymal interactions during growth and differentiation of different tissues and anatomic structures, including teats. Therefore, PTHLH and PTHR1 were evaluated as functional candidate genes for their effects on number and shape of teats in pigs. In particular, focus was on the occurrence and number of inverted teats, the most frequent and economically relevant teat developmental defect in pigs. For this purpose, association and linkage of the PTHLH gene and the PTHR1 gene with inverted teat defect and the total number of teats and inverted teats were studied in an experimental Duroc and Berlin Miniature pig (DUMI) population. Polymorphism C1819T of PTHR1 was significantly associated with inverted teat phenotype (p = 0.014), total number of teats (p = 0.047) and was close to significance with the number of inverted teats (p = 0.078). Polymorphism C375T of PTHLH was close to significance with the inverted teat phenotype (p = 0.122) and showed no significant association with the total number of teats (p = 0.621) and the number of inverted teats (p = 0.256) in the DUMI population. Association analyses were also performed for combined effects of PTHLH and PTHR1 in order to address potential interaction, however, revealed no indication of effects of interaction. The function, position and the association shown here promote PTHR1 as a candidate gene for number of teats and in particular for affection by and number of inverted teats.