Induced Mutations and Selection Techniques for Quantitative Traits

Abstract We induced mutations in Drosophila melanogaster males by treating them with 21.2 mm ethyl methanesulfonate (EMS). Nine quantitative traits (developmental time, viability, fecundity, longevity, metabolic rate, motility, body weight, and abdominal and sternopleural bristle numbers) were measured in outbred heterozygous F3 (viability) or F2 (all other traits) offspring from the treated males. The mean values of the first four traits, which are all directly related to the life history, were substantially affected by EMS mutagenesis: the developmental time increased while viability, fecundity, and longevity declined. In contrast, the mean values of the other five traits were not significantly affected. Rates of recessive X-linked lethals and of recessive mutations at several loci affecting eye color imply that our EMS treatment was equivalent to ∼100 generations of spontaneous mutation. If so, our data imply that one generation of spontaneous mutation increases the developmental time by 0.09% at 20° and by 0.04% at 25°, and reduces viability under harsh conditions, fecundity, and longevity by 1.35, 0.21, and 0.08%, respectively. Comparison of flies with none, one, and two grandfathers (or greatgrandfathers, in the case of viability) treated with EMS did not reveal any significant epistasis among the induced mutations.

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The effect of induced mutations on quantitative traits in Arabidopsis thaliana : Natural versus artificial conditions

Ecology and Evolution ◽

10.1002/ece3.2558 ◽

2016 ◽

Vol 6 (23) ◽

pp. 8366-8374 ◽

Cited By ~ 4

Author(s):

Frank W. Stearns ◽

Charles B. Fenster

Keyword(s):

Arabidopsis Thaliana ◽

Quantitative Traits ◽

Induced Mutations

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A pleiotropic nonadditive model of variation in quantitative traits.

Genetics ◽

10.1093/genetics/138.3.883 ◽

1994 ◽

Vol 138 (3) ◽

pp. 883-900 ◽

Cited By ~ 7

Author(s):

A Caballero ◽

P D Keightley

Keyword(s):

Quantitative Traits ◽

Spontaneous Mutation ◽

P Element ◽

Induced Mutations ◽

Bristle Number ◽

Degree Of Dominance ◽

Population Sizes ◽

Variable Gene ◽

Segregating Population ◽

New Mutations

Abstract A model of mutation-selection-drift balance incorporating pleiotropic and dominance effects of new mutations on quantitative traits and fitness is investigated and used to predict the amount and nature of genetic variation maintained in segregating populations. The model is based on recent information on the joint distribution of mutant effects on bristle traits and fitness in Drosophila melanogaster from experiments on the accumulation of spontaneous and P element-induced mutations. These experiments suggest a leptokurtic distribution of effects with an intermediate correlation between effects on the trait and fitness. Mutants of large effect tend to be partially recessive while those with smaller effect are on average additive, but apparently with very variable gene action. The model is parameterized with two different sets of information derived from P element insertion and spontaneous mutation data, though the latter are not fully known. They differ in the number of mutations per generation which is assumed to affect the trait. Predictions of the variance maintained for bristle number assuming parameters derived from effects of P element insertions, in which the proportion of mutations with an effect on the trait is small, fit reasonably well with experimental observations. The equilibrium genetic variance is nearly independent of the degree of dominance of new mutations. Heritabilities of between 0.4 and 0.6 are predicted with population sizes from 10(4) to 10(6), and most of the variance for the metric trait in segregating population is due to a small proportion of mutations (about 1% of the total number) with neutral or nearly neutral effects on fitness and intermediate effects on the trait (0.1-0.5 sigma P).(ABSTRACT TRUNCATED AT 250 WORDS)

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