Statistical analysis and experimental design for mapping genes of complex traits in domestic animals.

Gene mapping for complex traits has been an active and challenging research area in humans, agricultural and laboratory species. In domestic animals and poultry, the goal of gene mapping is to find genes associated with production, reproduction and health traits. In humans, gene mapping for complex diseases has been a significant challenge. Although gene mapping results are accumulating rapidly, confirmed results are scarce. In domestic animals, gene mapping results are also accumulating rapidly and several large scale mapping projects in chickens, swine, and dairy cattle are currently in progress. Although new and more reliable results can be expected in the near future, the precise understanding of genes underlying complex traits is still some distance away. Recently, the approach of mapping genes of complex traits has been applied to gene expression data to map transcription regulatory elements, adding a new dimension to gene mapping. Statistical analysis of gene mapping data and experimental design are critical components of a gene mapping research. The purpose of this review article is to discuss current status as well as future directions and challenges in statistical analysis and experimental design for mapping genes of complex traits in domestic animals and poultry.