Localizing genes using linkage disequilibrium in plants: integrating lessons from the medical genetics
Date
2007-03-19Author
Ochieng, J W
Muigai, A W T
Ude, G N
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
Finding genes controlling quantitative traits will aid molecular breeding for crops and livestock with
superior yields, growth rates, and evolutionary potential. Such genes can be located using the
candidate gene approach, genome wide scans, or by within family mapping. Linkage disequilibrium
(LD) or association mapping, is a candidate gene approach that relies on detecting a statistical
association between the desired quantitative trait and a molecular marker allele. This approach is
emerging as a leading tool for precise estimation of QTL positions, because it offers several
advantages over family-based mapping: LD mapping detects associations with greater resolution, the
associations detected are relevant population wide, and in plants, the use of natural populations would
circumvent the need to raise large controlled crosses. However, LD approach is facing obstacles, with
well over 60% of studies reporting associations in the medical genetics disapproved in subsequent
tests. A large proportion of these false associations (or lack of it) result from population stratification,
while the rest may be caused by other demographic and evolutionary processes that create a statistical
association between a marker allele and the trait, such as bottlenecks, natural selection, hybridization
and genetic drift. The problem is expected to escalate in plants, owing to the complex population
structures. Regardless of the many recent methods that purport to take into account population
stratification during association tests, we discuss the reasons why in plants, a priori knowledge of
population structures is essential in any robust association analysis.
URI
http://www.ajol.info/index.php/ajb/article/view/56872http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/35866
Citation
Ochieng, J. W, Muigai, A. W.T & Ude, G.N(2007). Localizing genes using linkage disequilibrium in plants: integrating lessons from the medical genetics.African Journal of Biotechnology; 6 (6)650-657.Publisher
Academic Journals Department of Animal Production, University of Nairobi
Subject
Association mappingLinkage disequilibrium
Population structure
Nonreplication
Quantitative trait loci.
Description
Journal article