Department of Statistics & Probability, Michigan State University, East Lansing, MI 48824, USA
Copyright © 2009 Gengxin Li and Yuehua Cui. This is an open access article distributed under the
Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current methods for mapping imprinted quantitative trait locus (iQTL) with inbred line
crosses assume fixed QTL effects. When an iQTL segregates in experimental line crosses,
combining different line crosses with similar genetic background can improve the accuracy
of iQTLs inference. In this article, we develop a general interval-based statistical variance
components framework to map iQTLs underlying complex traits by combining different
backcross line crosses. We propose a new iQTL variance partition method based on the
nature of marker alleles shared identical-by-decent (IBD) in inbred lines. Maternal effect is
adjusted when testing imprinting. Efficient estimation methods with the maximum likelihood
and the restricted maximum likelihood are derived and compared. Statistical properties of
the proposed mapping strategy are evaluated through extensive simulations under different
sampling designs. An extension to multiple QTL analysis is given. The proposed method
will greatly facilitate genetic dissection of imprinted complex traits in inbred line crosses.