Inbreeding depression maintained by recessive lethal mutations interacting with stabilizing selection on quantitative characters in a partially self-fertilizing population

Lande, Russell

doi:10.1111/evo.13225

Cited by 13 publications

(13 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Templeton & Read () suggested that a short period of intense inbreeding could rapidly purge inbreeding depression from a population. Although their empirical findings on purging are no longer considered reliable (Willis & Wiese, ), theory predicts that purging will most readily occur when inbreeding depression is primarily composed of a small number of lethal or near‐lethal recessive mutations (Charlesworth & Willis, ; Lande & Porcher, ).…”

Section: Introductionmentioning

confidence: 99%

Inbreeding depression is difficult to purge in self‐incompatible populations of Leavenworthia alabamica

Baldwin

Schoen

2019

New Phytologist

View full text Add to dashboard Cite

The extent to which inbreeding depression can be purged is a major determinant of mating system evolution and is important to conservation and crop improvement. Studies of inbreeding depression purging have not been conducted in self-incompatible plants before.An experimental ('ancestral') treatment was first created from self-incompatible plants of Leavenworthia alabamica. Lines derived from this population were maintained by self-pollination for three generations in the attempt to create a 'purged' population with fewer recessive, deleterious mutations of large effect. Fitness components and the frequency of malformed phenotypes were monitored in progeny derived from selfing and outcrossing in the ancestral and purged treatments.Fitness component means and inbreeding depression were largely unchanged by three generations of forced self-pollination, and there was no reduction in the frequency of plants exhibiting malformed phenotypes.Our findings indicate that inbreeding depression in this species is largely a result of mutations of mild effect, consistent with the observation that self-incompatibility is maintained in most populations of L. alabamica, despite the presence of genetic variants with weaker selfincompatibility. Moreover, although population theory suggests that deleterious mutations of large effect should be sheltered from selection in the region of self-incompatibility locus, our results do not support this prediction.

show abstract

Section: Introductionmentioning

confidence: 99%

Inbreeding depression is difficult to purge in self‐incompatible populations of Leavenworthia alabamica

Baldwin

Schoen

2019

New Phytologist

View full text Add to dashboard Cite

show abstract

“…Only modest effects of such interference among slightly deleterious mutations on levels of inbreeding depression in partially selfing populations have been found for multiplicative fitness models with dominance coefficients of the magnitude assumed here (Bersabé, Caballero, Pérez‐Figueroa, & García‐Dorado, ; Charlesworth, Morgan, & Charlesworth, ; Kamran‐Disfani & Agrawal, ; Roze, ), unless the population size is very small. Larger effects of interference may occur for the small dominance coefficients ( h ≤ 0.02) associated with severely deleterious or recessive lethal mutations (Kelly, ; Lande, ; Lande & Porcher, ; Porcher & Lande, ), leading to much higher frequencies of deleterious mutations than expected in the absence of interference, but the low values of B in most studies in Table suggest that the contributions from such mutations are minor. Indeed, they are likely to be purged from partially inbreeding populations, unless mutation rates are very high (Kelly, ; Lande & Schemske, ).…”

Section: Discussionmentioning

confidence: 99%

Mutational load, inbreeding depression and heterosis in subdivided populations

Charlesworth

2018

Molecular Ecology

View full text Add to dashboard Cite

& Hatfield, 2000). These have shown that the mutational load and inbreeding depression are generally increased by high migration rates and large local population sizes, while heterosis in betweenpopulation crosses is reduced. While the theoretical expectations are in qualitative agreement with the empirical results, no attempt has been made to determine whether the data quantitatively match theoretical predictions based on current estimates of mutation rates and the distribution of fitness effects of new deleterious mutations obtained from genomic data, reviewed by Keightley (2012) andCharlesworth (2015). Furthermore, the theoretical work has assumed that mutation rates per locus or nucleotide site are small, relative to the strength of selection against deleterious alleles. In addition, the forward mutation rate (from wild type to mutant) is usually assumed to be much greater than the backward mutation rate (from mutant to wild type), the latter often being ignored. The first assumption is usually well justified for mutations affecting protein sequences and strongly constrained functional non-coding sequences. The second assumption applies to the totality of mutations that affect a functional unit such as a coding sequence, provided that selection is sufficiently Abstract This paper examines the extent to which empirical estimates of inbreeding depression and interpopulation heterosis in subdivided populations, as well as the effects of local population size on mean fitness, can be explained in terms of current estimates of mutation rates, and the distribution of selection coefficients against deleterious mutations provided by population genomics data. Using population genetics models, numerical predictions of the genetic load, inbreeding depression and heterosis were obtained for a broad range of selection coefficients and mutation rates. The models allowed for the possibility of very high mutation rates per nucleotide site, as is sometimes observed for epiallelic mutations in plants. There was fairly good quantitative agreement between the theoretical predictions and empirical estimates of heterosis and the effects of population size on genetic load, on the assumption that the deleterious mutation rate per individual per generation is approximately one, but there was less good agreement for inbreeding depression. Weak selection, of the order of magnitude suggested by population genomic data, is required to explain the observed patterns. Possible caveats concerning the applicability of the models are discussed. K E Y W O R D Sepiallelic mutations, genetic load, heterosis, inbreeding depression, mutation rate, subdivided population

show abstract

“…Only modest effects of such interference among slightly deleterious mutations on levels of inbreeding depression in partially selfing populations have been found for multiplicative fitness models with dominance coefficients of the magnitude assumed here (Bersabé, Caballero, Pérez-Figuereoa, & García-Dorado, 2016;Charlesworth, Morgan & Charlesworth, 1992;Kamran-Disfani & Agrawal, 2014;Roze, 2015), unless the population size is very small. Larger effects of interference may occur for the small dominance coefficients (h ≤ 0.02) for severely deleterious or recessive lethal mutation (Kelly, 2007;Lande, 1994;Lande & Porcher, 2017;Porcher & Lande, 2016), leading to much higher frequencies of deleterious mutations than expected in the absence of interference, but the low values of B in most studies in Table S2 suggest that the contributions from such mutations are minor. Indeed, they are likely to be purged from partially inbreeding populations, unless mutation rates are very high (Lande & Schemske, 1985;Kelly, 2007).…”

Section: Caveats and Complicationsmentioning

confidence: 98%

Mutational load, inbreeding depression and heterosis in subdivided populations

Charlesworth

2018

Preprint

View full text Add to dashboard Cite

This paper examines the extent to which empirical estimates of inbreeding depression and inter-population heterosis in subdivided populations, as well as the effects of local population size on mean fitness, can be explained in terms of estimates of mutation rates, and the distribution of selection coefficients against deleterious mutations provided by population genomics data. Using results from population genetics models, numerical predictions of the genetic load, inbreeding depression and heterosis were obtained for a broad range of selection coefficients and mutation rates. The models allowed for the possibility of very high mutation rates per nucleotide site, as is sometimes observed for epiallelic mutations. There was fairly good quantitative agreement between the theoretical predictions and empirical estimates of heterosis and the effects of population size on genetic load, on the assumption that the deleterious mutation rate per individual per generation is approximately one, but there was less good agreement for inbreeding depression.Weak selection, of the order of magnitude suggested by population genomic analyses, is required to explain the observed patterns. Possible caveats concerning the applicability of the models are discussed.All rights reserved. No reuse allowed without permission.

show abstract

Inbreeding depression maintained by recessive lethal mutations interacting with stabilizing selection on quantitative characters in a partially self-fertilizing population

Cited by 13 publications

References 91 publications

Inbreeding depression is difficult to purge in self‐incompatible populations of Leavenworthia alabamica

Inbreeding depression is difficult to purge in self‐incompatible populations of Leavenworthia alabamica

Mutational load, inbreeding depression and heterosis in subdivided populations

Mutational load, inbreeding depression and heterosis in subdivided populations

Contact Info

Product

Resources

About