An experiment on recombination load in<i>Drosophila melanogaster</i>

Charlesworth, Brian; Charlesworth, Deborah

doi:10.1017/s001667230001569x

Cited by 50 publications

(46 citation statements)

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“…Apart from producing some infertility in heterozygous females through nondisjunction, a Robertsonian fusion might act directly on fitness through position effects, or by its reorganisation of the recombination pattern (see Hewitt and John, 1972;and Charlesworth and Charlesworth, 1975). Polymorphisms in each race would adapt themselves to the prevailing pattern of recombination, so that the rarer karyotype in the dine would tend to be selected against (see Bengtsson and Bodmer, 1976 for theoretical examples of the effect of an epistatic polymorphism on the evolution of a chromosomal rearrangement).…”

Section: Results (I) Crosses Between Pure Populationsmentioning

confidence: 99%

The fitness of hybrids between two chromosomal races of the grasshopper Podisma pedestris

Barton

1980

Heredity

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SUMMARYGenetic incompatibilities between two races of the grasshopper Podisnia pedestris, which differ by a Robertsonian fusion involving the sex chromosome, have been investigated. Crosses were made between four populations spanning the chromosomal dine; Fl hybrids between the races, though not between separated populations of the same race, showed markedly reduced hatching success.Observations of the fate of chromosomes transplanted across the dine supported this finding. Crosses between grasshoppers from a mixed population in the dine showed a lower average hatching success, but no correlation of this inviability with the chromosomal polymorphism. The karyotypes of pre-diapause embryos from both types of cross gave no evidence for non-disjunction of the sex chromosome trivalent in heterozygous females; an upper limit of 16 per cent can be set on the non-disjunction rate. These findings suggest that the karyotypic difference is only a weakly selected marker for more fundamental changes in genotype.

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Section: Results (I) Crosses Between Pure Populationsmentioning

confidence: 99%

The fitness of hybrids between two chromosomal races of the grasshopper Podisma pedestris

Barton

1980

Heredity

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“…Most of the experiments carried out in Drosophila have compared the fitness of chromosomes derived from males (which do not have recombination) with that of chromosomes derived from females (e.g., Spassky et al 1958;Dobzhansky et al 1959;Charlesworth and Charlesworth 1975). The abso-1 lute magnitude of recombination load, as measured by these experiments, is not great but strongly suggests a role for epistasis.…”

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confidence: 99%

“…Recombination load is the loss of fitness because recombination breaks up associations between beneficial combinations of interacting alleles (Charlesworth and Charlesworth 1975). Most of the experiments carried out in Drosophila have compared the fitness of chromosomes derived from males (which do not have recombination) with that of chromosomes derived from females (e.g., Spassky et al 1958;Dobzhansky et al 1959;Charlesworth and Charlesworth 1975).…”

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confidence: 99%

Recombination Load in a Chromosomal Inversion Polymorphism of Drosophila subobscura

Santos

2009

Genetics

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Chromosomal inversions suppress recombination in heterokaryotypes and may help to maintain positive epistatic interactions among groups of alleles at loci contained in the inversion. Here I evaluate the protective effect of inversions on recombination when different chromosomal segments, or even the whole chromosome O of Drosophila subobscura, can be effectively prevented from undergoing recombination in several naturally occurring heterokaryotypes. The fitness of flies made homozygous for recombinant chromosomes was generally lower when compared to their nonrecombinant counterparts, thus suggesting that segregating gene arrangements in this species hold together favorable combinations of alleles that interact epistatically.

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“…Recombination leads to the breakup of beneficial gene combinations (Barton and Charlesworth 1998), implying that offspring may suffer a recombination load (Charlesworth and Charlesworth 1975). Extra costs are incurred if sexual reproduction is also considered, such as the famous ''twofold cost '' (Maynard Smith 1978); sexual offspring need two parents whereas asexuals need one, so the latter can outgrow and outcompete sexuals.…”

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The Role of Advantageous Mutations in Enhancing the Evolution of a Recombination Modifier

2010

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Although the evolution of recombination is still a major problem in evolutionary genetics, recent theoretical studies have shown that recombination can evolve by breaking down interference (''HillRobertson effects'') among multiple loci. This leads to selection on a recombination modifier in a population subject to recurrent deleterious mutation. Here, we use computer simulations to investigate the evolution of a recombination modifier under three different scenarios of recurrent mutation in a finite population: (1) mutations are deleterious only, (2) mutations are advantageous only, and (3) there is a mixture of deleterious and advantageous mutations. We also investigate how linkage disequilibrium, the strength of selection acting on a modifier, and effective population size change under the different scenarios. We observe that adding even a small number of advantageous mutations increases the fixation rate of modifiers that increase recombination, especially if the effects of deleterious mutations are weak. However, the strength of selection on a modifier is less than the summed strengths had there been deleterious mutations only and advantageous mutations only.

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An experiment on recombination load inDrosophila melanogaster

Cited by 50 publications

References 11 publications

The fitness of hybrids between two chromosomal races of the grasshopper Podisma pedestris

The fitness of hybrids between two chromosomal races of the grasshopper Podisma pedestris

Recombination Load in a Chromosomal Inversion Polymorphism of Drosophila subobscura

The Role of Advantageous Mutations in Enhancing the Evolution of a Recombination Modifier

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