CGC Bibliography Paper 5548

Spontaneous mutational variation for body size in Caenorhabditis elegans.

Azevedo RBR, Keightley PD, Lauren-Maatta C, Vassilieva LL, Lynch M, Leroi AM

Medline:

12399386

Citation:

Genetics 165: 755-765 2002

Type:

ARTICLE

Genes:

Abstract:

We measured the impact of new mutations on genetic variation for body size in two independent sets of C. elegans spontaneous mutation-accumulation (MA) lines, derived from the N2 strain, that had been maintained by selfing for 60 or 152 generations. The two sets of lines gave broadly consistent results. The change of among-line genetic variation between cryopreserved controls and the MA lines implied that broad sense heritability increased by 0.4% per generation. Overall, MA reduced mean body size by similar to0.1% per generation. The genome-wide rate for mutations with detectable effects on size was estimated to be similar to0.0025 per haploid genome per generation, and their mean effects were similar to20%. The proportion of mutations that increase body size was estimated by maximum likelihood to be no more than 20%, suggesting that the amount of mutational variation available for selection for increased size could be quite small. This hypothesis was supported by an artificial selection experiment on adult body size, started from a single highly inbred N2 individual. We observed a strongly asymmetrical response to selection of a magnitude consistent with the input of mutational variance observed in the MA experiment.