Detecção de locos de características quantitativas nos cromossomos 9 e 10 de suínos / Detection of quantitative trait loci on pig chromosome 9 and 10

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

QTL are statistical associations of a genomic region and the phenotypic variation between segregating populations. The variation in a quantitative trait of interest can be related with the genotype of a molecular marker if this marker is close and linked to quantitative trait loci (QTL). To identify these associations, the mapping of chromosomes 9 and 10 was conducted in a F2 population composed of 714 animals derived from Piau X Commercial (Large White Landrace X Pietrain) crosses. The population was evaluated by performance, carcass, internal organs, viscera, carcass cuts and meat quality traits. Six microsatellites loci on chromosome 9 and three microsatellites loci on chromosome 10 were studied. The loci were analyzed for genic frequency, observed heterogosity, expected heterozigosity and polymorphic information content. Linkages maps were also constructed through the CRIMAP 2.4 program for the informative markers. The orders of all microsatellite loci were in accordance with the published USDA-MARC map. However, sex average maps of chromosomes 9 and 10 were, respectively, 27.75% and 124.60% longer than the published USDA-MARC. Association analyses were performed using interval mapping by regression for QTL detection. Three significant QTL to chromosomal levels were detected on chromosome 9 for total (bone-in) loin weight (P<0.01), boneless loin weight (P<0.05) and small intestine length (P<0.05), responding, respectively, by 6.7%, 4.0% and 4.9% of phenotypic variance. Two significant QTL to chromosomal levels have been detected on chromosome 10 for higher backfat thickness on the shoulder region (P<0.05) and redness (P<0.05), both responding by 2.4% of phenotypic variance and one significant QTL to genomic level for liver weight (P<0.01) responding by 6.9% of phenotypic variance. The generated information of significant QTL will be useful for future studies dealing with fine mapping and identification of genes that could provide a better understanding of physiology and production traits of pigs.

ASSUNTO(S)

pig microssatélite qtl genetica e melhoramento dos animais domesticos qtl microsatellites suíno

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