Morphometric studies in inbred and hybrid house mice. Heterosis, homeostasis and heritability of size and shape

Abstract

One size (SIZE) and four shape measures (SHAPE ]-SHAPE 4) were derived from a multiple group principal components analysis of 15 osteometric variables in inbred and hybrid house mice. In both sexes, SIZE and two of the four SHAPE variables showed positive heterosis, the other two SHAPE variables exhibiting negative heterosis. SIZE showed a greater magnitude of heterosis (average of about 2.3 standard deviations) than all SHAPE characters except SHAPE 2, a skull length/width contrast. Inbreds were more variable than hybrids (positive homeostasis) for all characters, and there was a significant, positive correlation between heterosis and homeostasis in these characters. The reciprocals category in hybrids was more important for SIZE than for the SHAPE variables, presumably because maternal effects have a greater influence on growth characters. Broad-sense heritabilities for SIZE were 0.8 in inbreds and 0.6 in hybrids whereas they averaged only 0.4 for the SHAPE variables. It was postulated that there is a greater number of loci governing SIZE compared to SHAPE, and that this explains both the heritability and heterosis differences between these characters.

Independence between developmental stability and canalization in the skull of the house mouse

“…The genetic bases of DS and canalization are for the most part unknown even though an important number of studies have focused on this subject in the last few decades, for example, Leamy & Thorpe (1984), Leamy (1993), Graham (1992) and Clarke (1993b) for DS and Wagner et al (1997) and Eshel & Matessi (1998) for canalization. Except in the case of Lucila cuprina studies, which have stressed the role of a modi¢er gene in DS regulation (e.g.…”

CORRELATIONS BETWEEN HETEROZYGOSITY AND PHENOTYPIC VARIABILITY INCOTTUS(TELEOSTEI: COTTIDAE): CHARACTER COMPONENTS

“…In quantitative genetic studies, "size free" shape measures are often constructed using ratios, which have considerable statistical (Atchley et aI., 1976) and interpretative (Bookstein et aI., 1985;Strauss, 1985) problems that detract from their usefulness. However, there seems to be no relationship between relative variability and heritability among mensural traits in either the polychaete Pi/eolaria pseudomilitaris (Beckwitt, 1981) or the amphipod Gammarus minus (Fong, 1988), nor among a series of metric characters (Atchley et a!., 1981) and multivariate size and shape factors (Leamy and Thorpe, 1984) in strains of rats and mice. Even if they exist, such correlations are likely to be age dependent (Atchley and Rutledge, 1980).…”

Multivariate Phenotypic Differentiation Among Bottleneck Lines of the Housefly

“…The evidence for this is equivocal. Leamy and Thorpe (1984), for example, found greater additive genetic variation associated with size than with shape in osteometric traits in inbred and hybrid house mice. On the other hand, Atchley et al (1981), found nearly uniform heritability of (varimax) rotated principal axes of morphometric traits in the rat.…”