Estudo da diversidade genÃtica de raÃas caprinas do norte da ItÃlia pela anÃlise de polimorfismos no gene do hormÃnio de crescimento - GH.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Northern Italyâs rugged terrain, associated with extreme variations in temperature and precipitation, make up generally unfavorable growing conditions for large ruminants (i.e. cattle). However, husbandry of small ruminants, like the domestic goat (Capra hircus), is greatly disseminated in this region. The use of local breeds is associated with the manufacturing of typical products that contribute to the richness of several regional traditions and customs. The objective of this project was to study the genetic diversity of these local breeds by analyzing the Growth Hormone polymorphisms naturally occurring in these populations. Our results will be useful for conservation initiatives of the local goat breeds and association studies with production traits measured in the respective herds, eventually leading to more efficient breeding strategies. A total of six local breeds were evaluated in addition to two commercial breeds and two distinct populations of a âprimitiveâ breed. Genomic DNA was extracted from blood samples and amplified by PCR at three overlapping regions of the goat GH named GA, 2/3 and GB. The PCR fragments were electrophoresed in SSCP gels and directly sequenced in the search for Single Nucleotide Polymorphisms (SNPs). The data generated were used to estimate genetic distances and population structure parameters for the studied breeds. The observed haplotype frequencies for the SSCP data from the GA fragment was used to estimate population genetic structure parameters that corroborate the historic and geographic distribution of the breeds. A total of 5 SNPs were identified in the intron regions of the GA fragment. Genetic distances estimated with the SNP data were discordant with the SSCP results. The 2/3 and GB fragments showed a high level of SSCP polymorphisms and continued analysis of the generated data will be extremely useful to test the postulated hypothesis.

ASSUNTO(S)

genetica sscp distÃncias genÃticas snp gh polimorfismo caprinos

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