Genetical Research



Mapping quantitative trait loci for murine growth: a closer look at genetic architecture


TY T. VAUGHN a1c1, L. SUSAN PLETSCHER a1, ANDREA PERIPATO a1, KELLY KING-ELLISON a1, EMILY ADAMS a1, CHRISTOPHER ERIKSON a1 and JAMES M. CHEVERUD a1
a1 Department of Anatomy and Neurobiology, Washington University School of Medicine, 600 South Euclid Avenue, St Louis, MO 63110, USA

Abstract

Over 20 years ago, D. S. Falconer and others launched an important avenue of research into the quantitative of body size growth in mice. This study continues in that tradition by locating quantitative trait loci (QTLs) responsible for murine growth, such as age-specific weights and growth periods, and examining the genetic architecture for body weight. We identified a large number of potential QTLs in an earlier F2 intercross (Intercross I) of the SM/J and LG/J inbred mouse strains. Many of these QTLs are replicated in a second F2 intercross (Intercross II) between the same two strains. These replicated regions provide candidate regions for future fine-mapping studies. We also examined body size and growth QTLs using the combined data set from these two intercrosses, resulting in 96 microsatellite markers being scored for 1045 individuals. An examination of the genetic architecture for age-specific weight and growth periods resulted in locating 20 separate QTLs, which were mainly additive in nature, although dominance was found to affect early growth and body size. QTLs affecting early and late growth were generally distinct, mapping to separate chromosome locations. This QTL pattern indicates largely separate genetic and physiological systems for early and later murine growth, as Falconer suggested. We also found sex-specific QTLs for body size with implications for the evolution of sexual dimorphism.

(Received April 21 1999)
(Revised June 23 1999)


Correspondence:
c1 Corresponding authors. Tel: +1 (314) 362 4189. Fax: +1 (314) 3446. e-mail: vaughnt@thalamus.wustl.edu


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