scholarly journals Fitness dependence preserves selection for recombination across diverse mixed mating systems

2020 ◽  
Author(s):  
Sviatoslav Rybnikov ◽  
Daniel B. Weissman ◽  
Sariel Hübner ◽  
Abraham B. Korol
Keyword(s):  
Evolutionary Biology ◽  
Mating Systems ◽  
Theoretical Models ◽  
Mixed Mating ◽  
Best Constant ◽  
Factors Affecting ◽  
Equal Rate ◽  
Selection For ◽  
Open Question ◽  
Fitness Dependence

AbstractMeiotic recombination and the factors affecting its rate and fate in nature have inspired many theoretical studies in evolutionary biology. Classical theoretical models have inferred that non-zero recombination can be favoured under a rather restricted parameter range. Thus, the ubiquity of recombination in nature remains an open question. However, these models assumed constant (uniform) recombination with an equal rate across all individuals within the population. Models of fitness-dependent recombination, with the rate varying among genotypes according to their fitness have shown that such a strategy can often be favoured over the best constant recombination. Here we use simulations to show that across a range of mating systems with varying frequencies of selfing and clonality, fitness-dependent recombination is often favoured even when any non-zero constant recombination is disfavoured. This recombination-protecting effect of fitness dependence is strongest under intermediate rates of selfing or high rates of clonality.

Fitness dependence preserves selection for recombination across diverse mixed mating strategies

2021 ◽  
pp. 110849
Author(s):  
Sviatoslav Rybnikov ◽  
Daniel B. Weissman ◽  
Sariel Hübner ◽  
Abraham B. Korol
Keyword(s):  
Mating Strategies ◽  
Mixed Mating ◽  
Selection For ◽  
Fitness Dependence

scholarly journals Selection for pollen competitive ability in mixed-mating systems

Evolution ◽  
2018 ◽  
Vol 72 (11) ◽  
pp. 2513-2536 ◽  
Author(s):  
Madeline A. E. Peters ◽  
Arthur E. Weis
Keyword(s):  
Competitive Ability ◽  
Mating Systems ◽  
Mixed Mating ◽  
Selection For

scholarly journals Selection for Pollen Competitive Ability in Mixed Mating Systems

2017 ◽  
Keyword(s):  
Plant Species ◽  
Analytical Solutions ◽  
Population Genetic ◽  
Competitive Ability ◽  
Mating Systems ◽  
Antagonistic Pleiotropy ◽  
Mixed Mating ◽  
Expression Of Genes ◽  
Counter Selection ◽  
Selection For

ABSTRACTCo-expression of genes in plant sporophytes and gametophytes allows correlated gametic and sporophytic selection. Theory predicts that, under outcrossing, an allele conferring greater pollen competitive ability should fix within a population unless antagonistic pleiotropy with the sporophyte stage is strong. However, under strong selfing, pollen competitiveness is immaterial as superior and inferior competitors are deposited on opposite stigmas, producing assortative competition. Because many plant species have mixed-mating systems, selfing should be critical in the spread and maintenance of pollen-expressed genes affecting competitiveness. We present two one-locus, two-allele population genetic models for the evolution of a locus controlling pleiotropic antagonism between pollen competitiveness and diploid fitness. Analytical solutions provide minimum and maximum selfing rates allowing invasion of alleles with greater diploid and haploid fitness respectively. Further, polymorphism is only maintained when diploid selection is recessive. Fixation of the allele conferring greater pollen competitiveness may be prevented, even with weak sporophytic counter-selection, with sufficiently high selfing. Finally, selfing expands and limits the range of haploid-diploid selection coefficients allowing polymorphism, depending on dominance and selfing mode.

Modified rescue and risk expectations for species with diverse mating systems and modes of inheritance

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Mating Systems ◽  
Outbreeding Depression ◽  
Mixed Mating ◽  
Genetic Rescue ◽  
Mode Of Inheritance

The risks of inbreeding and outbreeding depression, and the prospects for genetic rescue are often different in species with alternative mating systems and mode of inheritance (compared to outbreeding diploids), such as self-incompatible, self-fertilizing, mixed mating, non-diploid (haploid, haplodiploid and polyploid) and asexual.

Factors affecting the hydrogen cyanide potential of forage sorghum.

1990 ◽  
Vol 41 (6) ◽  
pp. 1093 ◽  
Author(s):  
JL Wheeler ◽  
C Mulcahy ◽  
JJ Walcott ◽  
GG Rapp
Keyword(s):  
Water Stress ◽  
Light Intensity ◽  
Hydrogen Cyanide ◽  
Dry Matter ◽  
Early Stage ◽  
Phosphorus Fertilizer ◽  
Factors Affecting ◽  
Forage Sorghum ◽  
Plant Maturity ◽  
Selection For

The effect of seven factors, namely genotype, plant maturity, nitrogen fertilizer, phosphorus fertilizer, water stress, light intensity and temperature, on the hydrogen cyanide potential (HCNp) of forage sorghum was studied in three pot experiments. Fivefold differences occurred between genotypes in HCNp, with a breeder's line, X45106, selected for low HCNp having a maximum of 520 mg HCN kg-1 DM (dry matter) compared with 2300 and 2450 mg kg-1 DM for cvs Zulu and Silk respectively. In X45 106, HCNp (mg HCN kg-1 DM) declined curvilinearly with age d (days from sowing) (HCNp=8460- 320d+ 3.1d2) and linearly in Silk (HCNp = 9020 - 110d), but the decline in Zulu was not statistically significant. Nitrogen (equivalent to 200 kg ha-1 of N) increased HCN, (P< 0.001), but more so in full light (100 mg kg-1 compared with 1430 mg kg-1) than in 50% shade (190 mg kg-1 compared with 690 mg kg-1). In one experiment, acute water stress appeared to reduce HCNp, but this was confounded with the strong decline due to aging. In another study, acute water stress had no effect on HCNp. Neither the application of superphosphate nor change in light intensity, nor change in temperature had a direct significant effect on HCNp in these studies. Breeding and selection for low HCNp appears a promising approach to ensuring that sorghum plants will provide non-toxic forage from an early stage of growth.

Plant mating systems and assessing population persistence in fragmented landscapes

2007 ◽  
Vol 55 (3) ◽  
pp. 239 ◽  
Author(s):  
David J. Coates ◽  
Jane F. Sampson ◽  
Colin J. Yates
Keyword(s):  
Mating System ◽  
Population Size ◽  
Mating Systems ◽  
Habitat Disturbance ◽  
Population Persistence ◽  
Population Variation ◽  
Conservation Strategies ◽  
Valuable Insight ◽  
Mixed Mating ◽  
Fragmented Landscapes

Population size and habitat disturbance are key factors likely to shape the mating system of populations in disturbed and fragmented landscapes. They would be expected to influence the availability and behaviour of the pollinator, the ability to find mates in self-incompatible species, inbreeding in self-compatible species and the size of the pollen pool. These in turn might be expected to influence key variables critical for population persistence such as seed production, seed germination and seedling fitness. Here we investigate mating-system variation in six rare species, i.e. Banksia cuneata, B. oligantha, Lambertia orbifolia (Proteaceae), Verticordia fimbrilepis subsp. fimbrilepis, Eucalyptus rameliana (Myrtaceae), Acacia sciophanes (Mimosaceae), and two common species, i.e. Calothamnus quadrifidus (Myrtaceae) and Acacia anfractuosa. All seven species are animal-pollinated relatively long-lived woody shrubs with mixed-mating systems. Population variation in mating-system parameters was investigated in relation to population size and habitat disturbance. We show that although the mating system will vary depending on pollination biology and life-history, as populations get smaller and habitat disturbance increases there is a trend towards increased inbreeding, smaller effective sizes of paternal pollen pools and greater variation in outcrossing among plants. From the species investigated in this study we have found that changes in the mating system can be useful indicators of population processes and can give valuable insight into the development of conservation strategies for the persistence of plant species following anthropogenic disturbance and landscape fragmentation.

scholarly journals Sex, amitosis, and evolvability in the ciliate Tetrahymena thermophila

2021 ◽  
Author(s):  
Jason A Tarkington ◽  
Hao Zhang ◽  
Ricardo Azevedo ◽  
Rebecca Zufall
Keyword(s):  
Genetic Variation ◽  
Experimental Evolution ◽  
Evolutionary Biology ◽  
Genetic Architecture ◽  
Nuclear Division ◽  
Tetrahymena Thermophila ◽  
Laboratory Populations ◽  
Evolutionary Success ◽  
Sexual Progeny ◽  
Open Question

Understanding the mechanisms that generate genetic variation, and thus contribute to the process of adaptation, is a major goal of evolutionary biology. Mutation and genetic exchange have been well studied as mechanisms to generate genetic variation. However, there are additional processes that may also generate substantial genetic variation in some populations and the extent to which these variation generating mechanisms are themselves shaped by natural selection is still an open question. Tetrahymena thermophila is a ciliate with an unusual mechanism of nuclear division, called amitosis, which can generate genetic variation among the asexual descendants of a newly produced sexual progeny. We hypothesize that amitosis thus increases the evolvability of newly produced sexual progeny relative to species that undergo mitosis. To test this hypothesis, we used experimental evolution and simulations to compare the rate of adaptation in T. thermophila populations founded by a single sexual progeny to parental populations that had not had sex in many generations. The populations founded by a sexual progeny adapted more quickly than parental populations in both laboratory populations and simulated populations. This suggests that the additional genetic variation generated by amitosis of a heterozygote can increase the rate of adaptation following sex and may help explain the evolutionary success of the unusual genetic architecture of Tetrahymena and ciliates more generally.

scholarly journals EVOLUTION OF INTERACTIONS IN FAMILY-STRUCTURED POPULATIONS: MIXED MATING MODELS

Genetics ◽  
1980 ◽  
Vol 96 (1) ◽  
pp. 275-296
Author(s):  
Richard E Michod
Keyword(s):  
Mating System ◽  
Mating Systems ◽  
Random Mating ◽  
Additive Model ◽  
Multiplicative Model ◽  
Structured Populations ◽  
Mixed Mating ◽  
Genotypic Distribution ◽  
Individual Fitness ◽  
Recessive Genes

ABSTRACT The effect of inbreeding on sociality is studied theoretically for the evolution of interactions between siblings in certain mixed mating systems that give rise to inbreeding: sib with random mating and selfing with random mating. Two approaches are taken. First, specific models of altruism are studied for the various mating systems. In the case of the additive model, inbreeding facilitates the evolution of altruistic genes. Likewise, for the multiplicative model this is usually the case, as long as the costs of altruism are not too great. Second, the case of total altruism, in which the gene has zero individual fitness but increases the fitness of associates, is studied for a general fitness formulation. In this case, inbreeding often retards the ability of such genes to increase when rare, and the equilibrium frequency of those recessive genes that can increase is totally independent of the mating system and, consequently, of the amount of inbreeding. It appears from the results presented that inbreeding facilitates most forms of altruism, but retards extreme altruism. These results stem from the fact that inbreeding increases the within-family relatedness by increasing the between-family variance in allele frequency. In most cases this facilitates altruism. However, in the case of total altruism, only heterozygotes can pass on the altruistic allele, and inbreeding tends to decrease this heterozygote class. In either case, the important effect of inbreeding lies in altering the genotypic distribution of the interactions.

Sign in / Sign up

Export Citation Format

Share Document