Research of precocious criteria of selection in meat cattle by the analysis of components of the somatotropic axis
1995
Sneyers, M.
The somatotropin (GH) and its mediators, the "insulin-like growth factors" (IGFs) but also their cellular receptors and their plasmatic transport proteins (GHBPs and IGFBPs) assume an important position in the complex phenomenon of minimal growth. In this regard, they present potential candidates for an analytic approach of research of precocious criteria of selection for the improvement of meat cattle growth performances. Our research has revealed that molecules of the somatotropic axis are the subject of variations in the bovine population; some of them are correlated with growth parameters. In particular, young bulls of the same age, placed in a controlled environment can show variable rates of GHBPs and IGFBPs. The cDNA coding for components of the hypophyseal-hepatic axis have been cloned, characterised and used to analyse the variability of the corresponding genes. Through PCR and sequencing, 17 polymorphic loci have been observed in the GH receptor (GIR). Restriction fragment length polymorphisms (RFLPs) have been identified with the Taql enzyme for the GH genes, the frequencies of the different genotypes vary from one breed to the other. A significant effect of the GH/Taql genotype on the height of 13 month-old Belgian White Blue breed bulls has been revealed.
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