International Mammalian Genome Society

The 15th International Mouse Genome Conference (2001)


POSTER 55 - RIX MAPPING: A DEMONSTRATION USING CXB RIX HYBRIDS TO MAP QTLS MODULATING BRAIN WEIGHT IN MICE

Dr. Robert W. Williams
University of Tennessee
Center of Genomics and Bioinformatics
Department of Anatomy and Neurobiology
855 Monroe Avenue
Memphis TN 38163
USA

Co-Authors: 1)Threadgill DW, 2)Manly KF, 2)Airey DC, 2)Lu L
Institutions: 1)Department of Genetics, UNC Chapel Hill NC; 2)Roswell Park Cancer Center, Buffalo

Recombinant inbred intercross (RIX) mapping is a new QTL mapping method that extends the power of recombinant inbred (RI) strains. RIX mapping involves generating isogenic F1s by crossing fully genotyped RI strains. Here we demonstrate the power of RIX mapping using the CXB set consists of the 13 RI strains (42 cases/strain), and 74 of 78 nonreciprocal F1 RIX hybrids (~16 cases/RIX). RIX mapping has 7 advantages: 1. increased power to detect QTLs; 2. improved resolution; 3. additive, dominance, and epistatic effects can be detected and measured; 4. measurement errors and environmental variance can be reduced by testing many isogenic F1 animals; 5. no genotyping is required (genotypes are inferred from RI parents); 6. RIX data are cumulative, enabling multivariate approaches; 7. parental effects can be detected from reciprocal RIX lines. The RIX method also has two disadvantages: 1. a paucity of RI strains on which to base an RIX cross; 2. strong statistical association between non-syntenic chromosomal intervals in existing RI strains carries through to RIX lines. Based on our RIX panel (n = 1300) we discovered 18 intervals linked to variation in brain weight. After controlling for non-syntenic association, we retained three independent and significant QTLs. In comparison, our analysis of the CXB parental data failed to detect any brain weight QTLs.

Supported by P20 MH62009.


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