title: Identification of novel candidate genes for the inverted teat defect in sows using a genome-wide marker panel.
abstract: The number of functional teats is an important selection criterion in pig breeding. Inherited defects of the udder, such as the inverted teat, do have a considerable negative impact on the nursing ability of the sow. To investigate the genetic background of this defect and the number of functional teats in Swedish maternal lines, samples from 230 Yorkshire pigs were selected for genotyping using the PorcineSNP60K BeadChip (Illumina Inc.), each pig with at least one inverted teat was matched with one non-affected pig (fullsib or pairs with matching herd and gender). A genome-wide association study on these 230 pigs was performed using the two-step approach implemented in GenABEL using 46,652 single nucleotide polymorphisms across all autosomes and the X chromosome. A number of significant regions were identified for the inverted teat defect on chromosomes 2, 10, and 18. Many of the regions associated with the number of functional teats were located in the same or close regions, except two associated markers on the X chromosome and one on chromosome 3. We identified some of the regions on chromosomes previously reported in one linkage and one gene expression study. We conclude, despite being able to suggest new candidate genes, that further studies are needed to better understand the biologic background of the teat development. Despite the in-depth comparison of identified regions for the inverted teat defect done here, more studies are required to allow a clear identification of genetic regions relevant for this defect across many pig populations.
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, SE-750 07, Uppsala, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Chalkias
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, SE-750 07, Uppsala, Sweden. elisabeth.jonas@slu.se.
authors.forename: Elisabeth
authors.identifier: http://orcid.org/0000-0003-4950-2549
authors.initials: E
authors.lastname: Jonas
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, SE-750 07, Uppsala, Sweden.
authors.forename: Lisa S
authors.initials: LS
authors.lastname: Andersson
authors.affiliation: Department of Clinical Sciences, Swedish University of Agricultural Sciences, Box 7054, SE-750 07, Uppsala, Sweden.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Jacobson
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, SE-750 07, Uppsala, Sweden.
authors.forename: Dirk Jan
authors.initials: DJ
authors.lastname: de Koning
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, SE-750 07, Uppsala, Sweden.
authors.forename: Nils
authors.initials: N
authors.lastname: Lundeheim
authors.affiliation: Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, SE-750 07, Uppsala, Sweden.|Capilet Genetics AB, SE-725 93, Västerås, Sweden.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Lindgren
mesh_terms: D000818:Animals; D001947:Breeding; D005260:Female; D005819:Genetic Markers; D055106:Genome-Wide Association Study / Q000662:veterinary*; D005838:Genotype; D008321:Mammary Glands, Animal / Q000002:abnormalities*; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D034421:Sus scrofa / Q000235:genetics*; D014960:X Chromosome
chemical_list: D005819:Genetic Markers
keywords: Functional teats; Genetic markers; Genome-wide association study; SNP; Teat number; Yorkshire breed