Characterization of the DGAT1 K232A and variable number of tandem repeat polymorphisms in French dairy cattle.
J Dairy Sci
; 90(6): 2980-8, 2007 Jun.
Article
en En
| MEDLINE
| ID: mdl-17517739
ABSTRACT
A quantitative trait locus (QTL) underlying different milk production traits has been identified with a high significance threshold value in the genomic region containing the acylCoAdiacylglycerol acyltransferase (DGAT1) gene, in the 3 main French dairy cattle breeds French Holstein, Normande, and Montbéliarde. Previous studies have confirmed that the K232A polymorphism in DGAT1 is responsible for a major QTL underlying several milk production traits in Holstein dairy cattle and several other bovine breeds. In this study, we estimate the frequency of the 2 alternative alleles, K and A, of the K232A polymorphism in French Holstein, Normande, and Montbéliarde breeds. Although the K allele segregates in French Holstein and Normande breeds with a similar effect on production traits, the existence of additional mutations contributing to the observed QTL effect is strongly suggested in both breeds by the existence of sires heterozygous at the QTL but homozygous at the K232A polymorphism. One allele at a variable number of tandem repeats (VNTR) locus in the 5' noncoding region of DGAT1 has been recently proposed as a putative causative variant. In our study, this marker was found to present a high mutation rate of 0.8% per gamete and per generation, making the allele diversity observed compatible with that expected under neutrality. Moreover, among the sires homozygous at the K232A polymorphism, no allele at the VNTR can fully explain their QTL status. Finally, no allele at the VNTR was found to be significantly associated with the fat percentage variation in the 3 breeds simultaneously after correction for the effect of the K232A polymorphism. Therefore, our results suggest the existence of at least one other causative polymorphism not yet described. Because the A allele is nearly fixed in the Montbéliarde breed, this breed represents an interesting model to identify and confirm other mutations that have a strong effect on milk production traits.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Lactancia
/
Bovinos
/
Repeticiones de Minisatélite
/
Leche
/
Diacilglicerol O-Acetiltransferasa
Tipo de estudio:
Prognostic_studies
Límite:
Animals
País/Región como asunto:
Europa
Idioma:
En
Revista:
J Dairy Sci
Año:
2007
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA