title: A primary screen of the bovine genome for quantitative trait loci affecting twinning rate.
abstract: An autosomal genome scan for quantitative trait loci (QTL) affecting twinning rate was carried out in the Norwegian Cattle population. Suggestive QTL were detected on Chromosomes (Chr) 5, 7, 12, and 23. Among these, the QTL positions on both Chr 5 and Chr 23 are strongly supported by literature in the field. Our results also confirm previous mapping of a QTL for twinning to Chr 7, but definitely suggest a different location of the QTL on this chromosome. The most convincing QTL peak was observed for a region in the middle part of Chr 5 close to the insulin-like growth factor 1 (IGF1) gene. Since IGF1 plays an important role in the regulation of folliculogenesis, a mutation search was performed by sequencing more than 3.5 kb of the gene in actual families. The sequencing revealed three polymorphisms in noncoding regions of the gene that will be important in fine structure mapping and characterization of the QTL.
authors.affiliation: Department of Animal Science, Agricultural University of Norway, Box 5025, N-1432 Aas, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Lien
authors.forename: A
authors.initials: A
authors.lastname: Karlsen
authors.forename: G
authors.initials: G
authors.lastname: Klemetsdal
authors.forename: D I
authors.initials: DI
authors.lastname: Våge
authors.forename: I
authors.initials: I
authors.lastname: Olsaker
authors.forename: H
authors.initials: H
authors.lastname: Klungland
authors.forename: M
authors.initials: M
authors.lastname: Aasland
authors.forename: B
authors.initials: B
authors.lastname: Heringstad
authors.forename: J
authors.initials: J
authors.lastname: Ruane
authors.forename: L
authors.initials: L
authors.lastname: Gomez-Raya
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics*; D002874:Chromosome Mapping; D002875:Chromosomes; D005820:Genetic Testing; D005838:Genotype; D008297:Male; D019655:Quantitative Trait, Heritable; D014427:Twins / Q000235:genetics