Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/18/2001
Publication Date: 12/31/2002
Citation: Lipkin, E., Fulton, J., Cheng, H.H., Yonash, N., Soller, M. 2002. Quantitative trait locus mapping in chicken by selective DNA pooling with dinucleotide microsatellite markers using purified DNA and fresh or frozen red blood cells as applied to marker-assisted selection. Poultry Science. 81:283-292. Interpretive Summary: The field of genomics has great potential for all species, in addition to humans. Particularly relevant to the poultry industry, genomic research may enable the breeding of chicken lines with superior meat yield, egg production, or disease resistance. Prior to this occurring, the important genes need to be identified and located. In this paper, we describe a more efficient method to identify important genes, which also can use samples that have been stored for many years. This method should enable scientists to rapidly find genes, and the poultry breeding industry to develop genetic tests to select superior animals. Ultimately, consumers would benefit from more economical and safe poultry food products.
Technical Abstract: Large numbers of large half-sib sire families are an integral component of chicken genetic improvement programs. These family structures include a sufficient number of individuals for QTL mapping at high statistical power. However, realizing this statistical power through individual or selective genotyping is as yet too costly to be feasible under current genotyping methodologies. Genotyping costs can be greatly reduced through selective DNA pooling, involving densitometric estimates of marker allele frequencies in pooled DNA samples. When using microsatellite markers, however, such estimates are often confounded by overlapping "shadow" bands, and can be confounded further by differential amplification of alleles. In the present study a shadow correction procedure (Lipkin et al., 1998) was found to provide accurate densitometric estimates of allele frequency in pools made up of chicken purified DNA samples, fresh blood samples, or frozen-thawed blood samples. In a retrospective study, selective DNA pooling using thawed blood samples that had been frozen for two years, successfully identified two QTL previously shown by total population genotyping to affect resistance in chickens to Marek's disease. It is proposed that the use of selective DNA pooling with frozen blood samples, can provide relatively low-cost mapping and utilization in marker- assisted selection, of QTL affecting production traits in chickens.