RESUMEN
There is evidence that stearoyl-CoA desaturase (SCD) is a key enzyme for lipid metabolism. Changes in enzyme activity that depends on SCD gene polymorphism and regulation could cause variations of fatty acid composition of meat and milk. We investigated genetic variability in caprine SCD, analyzing 335 animals belonging to three goat breeds by single-strand conformation polymorphism and DNA sequencing. Six single nucleotide polymorphism were identified, in intron 3 (585T-->A and 601A-->G; Ref. AF422168), intron 4 (719T-->A; AF422169), and exon 6 (690 A-->G, 718 C-->G, and 802 A-->C; AF422171). The less polymorphic SNP 601A-->G displayed variability only in Xuhuai and Boer breeds. Across breeds, the average frequency for the least frequent alleles ranged from 0.1158 to 0.2532. The three SNPs in exon 6 resulted in variations of amino acids 313 tyr --> cys, 322 phe --> leu, and 350 arg --> ser. The allelic distribution in exon 6 of Xuhuai was significantly different from Boer and Haimen.
Asunto(s)
Cabras/genética , Polimorfismo de Nucleótido Simple , Estearoil-CoA Desaturasa/genética , Animales , Ácidos Grasos/metabolismo , Frecuencia de los Genes , Marcadores Genéticos/genética , Cabras/anatomía & histología , Cabras/metabolismo , Carne , Polimorfismo Conformacional Retorcido-SimpleRESUMEN
Single nucleotide polymorphisms (SNPs) of hircine myf-5, myf-6 genes and 5'flanking region of the myoD gene (myoD 5') were analyzed by PCR-SSCP in Boer goat and Xuhuai white goat. Three genotypes were found at the myf-5 locus of Xuhuai white goat, denoted AA, AB and BB, while all of Boer goats were of AA genotype. Only AA and AB genotypes were found at myf-6 and myoD 5' loci. The effects of genotypes of myf-5, myf-6 and myoD 5'flanking region loci on body measurement traits were estimated. The results showed that genotypes at the myf-5 locus were significantly associated with hucklebone width and hucklebone width index in Xuhuai white goat (P<0.05). Genotypes at the myf-6 locus were significantly associated with withers heights and hucklebone width index in Boer goat (P<0.05), but no significant associations were found for any traits in Xuhuai white goat. The myoD 5' locus was not significantly associated with any traits in both types of goat.