scholarly journals Sexual selection for rare beneficial mutations promotes the evolution of sexual reproduction and adaptation

2021 ◽  
Author(s):  
Gilbert Roberts ◽  
Marion Petrie
Keyword(s):  
Sexual Selection ◽  
Sexual Reproduction ◽  
Negative Impact ◽  
Reproductive Rate ◽  
Beneficial Mutations ◽  
Selection For ◽  
The Cost ◽  
Average Fitness ◽  
Cost Of Sex

The evolution and widespread maintenance of sexual reproduction remains a conundrum in biology because asexual reproduction should allow twice the reproductive rate. One hypothesis is that sexual selection lessens the negative impact on fitness of accumulating deleterious mutations. However, for adaptation to occur, there must also be selection for beneficial mutations. Here we show that sexual selection can help explain the evolution and maintenance of sexual reproduction. In our model, females chose males with more beneficial mutations (as opposed to just fewer harmful ones) even when these occurred much more rarely. Sexual selection thereby increased fixation of beneficial mutations which increased the absolute genetic quality of sexual offspring. This increase in fitness relative to asexual offspring adds to the previously postulated effect of reduced mutation load in offsetting the cost of sex. Analysing our simulations reveals that female choice among males raised the fitness of reproducing males above that of females. We found that this effect could overcome the decline in average fitness that occurs when mutation rate increases, allowing an increase in the fixation of beneficial mutations. Sexual selection thereby not only facilitates the evolution of sexual reproduction but maintains sex by leveraging its benefits and driving adaptation.

scholarly journals Understanding sex differences in the cost of terrestrial locomotion

2011 ◽  
Vol 279 (1729) ◽  
pp. 826-832 ◽  
Author(s):  
John J. Lees ◽  
Robert L. Nudds ◽  
Lars P. Folkow ◽  
Karl-Arne Stokkan ◽  
Jonathan R. Codd
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Male And Female ◽  
Locomotor System ◽  
Terrestrial Locomotion ◽  
Female Data ◽  
Selection For ◽  
Morphological Differences ◽  
Lagopus Muta ◽  
The Cost

Little is known regarding the physiological consequences of the behavioural and morphological differences that result from sexual selection in birds. Male and female Svalbard rock ptarmigans ( Lagopus muta hyperborea ) exhibit distinctive behavioural differences during the breeding season. In particular, males continuously compete for and defend territories in order to breed successfully, placing large demands on their locomotor system. Here, we demonstrate that male birds have improved locomotor performance compared with females, showing both a lower cost of locomotion (CoL) and a higher top speed. We propose that the observed sex differences in locomotor capability may be due to sexual selection for improved male performance. While the mechanisms underlying these energetic differences are unclear, future studies should be wary when pooling male and female data.

scholarly journals Sexual selection and its effect on the fixation of an asexual clone

2006 ◽  
Vol 2 (4) ◽  
pp. 536-538 ◽  
Author(s):  
Marcel Salathé
Keyword(s):  
Sexual Selection ◽  
Sexual Reproduction ◽  
Mutation Rates ◽  
Male Mating ◽  
Mutational Load ◽  
Deleterious Mutations ◽  
Sexual Population ◽  
Fitness Advantage ◽  
Genomic Mutation ◽  
Cost Of Sex

Sexual selection is a powerful and ubiquitous force in sexual populations. It has recently been argued that sexual selection can eliminate the twofold cost of sex even with low genomic mutation rates. By means of differential male mating success, deleterious mutations in males become more deleterious than in females, and it has been shown that sexual selection can drastically reduce the mutational load in a sexual population, with or without any form of epistasis. However, any mechanism that claims to maintain sexual reproduction must be able to prevent the fixation of an asexual mutant clone with a twofold fitness advantage. Here, I show that despite very strong sexual selection, the fixation of an asexual mutant cannot be prevented under reasonable genomic mutation rates. Sexual selection can have a strong effect on the average mutational load in a sexual population, but as it cannot prevent the fixation of an asexual mutant, it is unlikely to play a key role on the maintenance of sexual reproduction.

scholarly journals Same-sex sexual behavior and selection for indiscriminate mating

2020 ◽  
Author(s):  
Brian A Lerch ◽  
Maria R Servedio
Keyword(s):  
Sexual Behavior ◽  
Sexual Reproduction ◽  
Optimal Strategy ◽  
Strong Support ◽  
Same Sex ◽  
Evolutionary Origins ◽  
Wide Range ◽  
Selection For ◽  
The Cost ◽  
Time And Energy

The widespread presence of same-sex sexual behavior (SSB) has long been thought to pose an evolutionary conundrum1-3, as participants in SSB suffer the cost of failing to reproduce after expending the time and energy to find a mate. The potential for SSB to occur as part of an optimal strategy has received almost no attention, although indiscriminate sexual behavior may be the ancestral mode of sexual reproduction4. Here, we build a simple model of sexual reproduction and create a theoretical framework for the evolution of indiscriminate sexual behavior. We provide strong support for the hypothesis that SSB is likely maintained by selection for indiscriminate sexual behavior, by showing that indiscriminate mating is the optimal strategy under a wide range of conditions. Further, our model suggests that the conditions that most strongly favor indiscriminate mating were likely present at the origin of sexual behavior. These findings have implications not only for the evolutionary origins of SSB, but also for the evolution of discriminate sexual behavior across the animal kingdom.

scholarly journals Conspecific sperm precedence is reinforced but sexual selection weakened in sympatric populations ofDrosophila

2016 ◽  
Author(s):  
Dean M. Castillo ◽  
Leonie C. Moyle
Keyword(s):  
Sexual Selection ◽  
Reproductive Isolation ◽  
Sperm Competition ◽  
Competitive Ability ◽  
Genetic Basis ◽  
Direct Selection ◽  
Sperm Precedence ◽  
Sympatric Populations ◽  
Selection For ◽  
The Cost

SUMMARYSexual selection is well recognized as a driver of reproductive isolation between lineages. However, selection for increased reproductive isolation could reciprocally change the outcomes of sexual selection, when these processes share a genetic basis. Direct selection for reproductive isolation occurs in the context of ‘reinforcement’, where selection acts to increase prezygotic barriers to reduce the cost of heterospecific matings. Many studies of reinforcement focus on premating reproductive barriers, however postmating traits-such as conspecific sperm precedence (CSP)-can also respond to reinforcing selection. We tested whether i) CSP responded to reinforcing selection, and ii) this response in sympatric populations altered intraspecific sperm competition (ISC) and the strength of sexual selection, with the sister speciesDrosophila pseudoobscuraandD. persimilis. We used sperm competition experiments to evaluate differences in CSP and ISC between two sympatric and two allopatric populations ofD. pseudoobscura. Using multiple genotypes for each population allowed us to estimate not only patterns of phenotype divergence, but also the opportunity for sexual selection within each population. Consistent with a pattern of reinforcement, the sympatric populations had higher mean CSP. Moreover, ISC was altered in sympatric populations, where we observed decreased average offensive sperm competitive ability against conspecific males, allowing less opportunity for sexual selection to operate within these populations. These data demonstrate that strong reinforcing selection for reproductive isolation can have consequences for sexual selection and sexual interactions within species, in these important postmating sperm competition traits.

scholarly journals Pharmacoeconomic aspects of glaucoma therapy with prostaglandin analogues in patients with signs of ocular surface disease

2015 ◽  
Vol 8 (1) ◽  
pp. 99-103
Author(s):  
Alla Vsevolodovna Rudakova
Keyword(s):  
Quality Of Life ◽  
Clinical Efficacy ◽  
Ocular Surface ◽  
Negative Impact ◽  
Ocular Surface Disease ◽  
Prostaglandin Analogues ◽  
The Cost ◽  
Ophthalmic Solutions ◽  
Preservative Free

Treatment of glaucoma is prevalent in modern healthcare. The standard of care at this time in the majority of glaucoma patients is to be treated with prostaglandin analogues. The aim of the present study was to compare the cost-effectiveness and the effect on the daily quality of life of preservative-free tafluprost to benzalkonium chloride (BAK) preserved latanoprost ophthalmic solutions which are present on the Russian market. In the patients with signs of ocular surface disease. Material and methods. The cost calculation was carried out on the basis of the weighted average retail price in Moscow from March 2015. The research was carried out over a 1 yeartime period. At the assessment, we assumed that clinical efficacy of the compared drugs did not differ; but at the same time the absence of the negative impact of treatment on patients’ quality of life (QoL), assessed by COMTol questionnaire, was observed in 30 % of patients treated with BAK-preserved latanoprost and in 52 % of patients treated with preservative-free tafluprost. Results and discussion. The costs of glaucoma treatment with preservative-free tafluprost and with branded BAK-preserved latanoprost are now comparable. The cost per 1 patient without the negative impact of treatment on patients’ QoL for tafluprost (Taflotan®) was 42.6 % lower than that for branded latanoprost (Xalatan®), 72.7 % higher than that for the generic latanoprost Glaumax®, and 24.3 % higher than that for the generic latanoprost Latanomol™. The analysis of the results’ sensitivity to changes in the cost of drugs in real limits demonstrated their high reliability. When taking a decision on the reimbursement for prostaglandin analogues, one should be aware that generic latanoprost ophthalmic solutions may differ significantly from the branded drug both in physical and chemical properties as well as in clinical efficacy and safety. Conclusion. Preservative-free tafluprost and branded BAK-preserved latanoprost are characterized by comparable clinical efficacy whereas preservative-free tafluprost has better tolerability. At a comparable cost of treatment, preservative-free tafluprost has a higher cost-effectiveness. This allows recommending its inclusion in regional and federal programs for the treatment of glaucoma in patients with ocular surface disease signs.

Opportunities and possible methods to improve reproduction in the pig

1988 ◽  
Vol 12 ◽  
pp. 221-237 ◽  
Author(s):  
Rodger K. Johnson ◽  
Steven M. Neal
Keyword(s):  
Litter Size ◽  
Economic Value ◽  
Genetic Selection ◽  
Reproductive Rate ◽  
Genetic Changes ◽  
Reproductive Maturity ◽  
Lean Meat ◽  
Pig Production ◽  
Selection For ◽  
The Cost

Genetic selection for litter size received little attention either by scientists or commercial pig breeders until recently. Low heritability of litter size, its sex-limited expression and the fact that it cannot be measured until reproductive maturity are often given as reasons. But the major reason may be that the reproductive rate of pigs is already quite high, and the economic value of genetic changes in litter size have been small relative to those of efficiency and composition of growth.The economics of pig production have changed and technological and biological advances have caused us to re-examine the economic value of traits. Reducing fat in the carcass and more efficient conversion of feed to lean meat have always been, and will continue to be, high priority selection objectives for pig breeders. But expensive, environmentally controlled gestation, farrowing and nursery houses are the norm of modern pig production and increasing litter size will result in a significant reduction in the cost of producing lean meat (Tess et al., 1983).

scholarly journals Increased adaptability to rapid environmental change can more than make up for the two-fold cost of males

2018 ◽  
Author(s):  
Caroline M. Holmes ◽  
Ilya Nemenman ◽  
Daniel B. Weissman
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Environmental Change ◽  
Male Fitness ◽  
Rapid Adaptation ◽  
Direct Competition ◽  
The Cost ◽  
Enormous Number ◽  
Rapid Environmental Change ◽  
Cost Of Sex

AbstractThe famous “two-fold cost of sex” is really the cost of anisogamy – why should females mate with males who do not contribute resources to offspring, rather than isogamous partners who contribute equally? In typical anisogamous populations, a single very fit male can have an enormous number of offspring, far larger than is possible for any female or isogamous individual. If the sexual selection on males aligns with the natural selection on females, anisogamy thus allows much more rapid adaptation via super-successful males. We show via simulations that this effect can be sufficient to overcome the two-fold cost and maintain anisogamy against isogamy in populations adapting to environmental change. The key quantity is the variance in male fitness – if this exceeds what is possible in an isogamous population, anisogamous populations can win out in direct competition by adapting faster.

scholarly journals Research on the Influencing Factors of Commercial Banks’ Bad Loans under the New Normal of Economy

2021 ◽  
Vol 6 (1) ◽  
pp. 411
Author(s):  
Lanyu Zhang ◽  
Yilin Zang ◽  
Chenxuan Wu
Keyword(s):  
Commercial Banks ◽  
Negative Impact ◽  
Positive Impact ◽  
New Normal ◽  
Leverage Ratio ◽  
Three Phase ◽  
Income Ratio ◽  
Asset Quality ◽  
The Cost

China is currently in a complex period of “three-phase superposition”. Under the new normal of the economy Financial deleveraging has achieved certain results. However, the non-performing loan ratio of commercial banks has shown a continuous upward trend since 2015. The empirical results show that the degree of internalization of commercial banks, credit balances, and gross domestic product have a negative impact on the NPL ratio, and the cost-to-income ratio and leverage ratio have a positive impact on the NPL ratio. Therefore, commercial banks should vigorously develop digital technology, expand the scale of credit, use technological advantages to reduce costs, establish an appropriate level of leverage, and effectively reduce the non-performing loan ratio to improve the asset quality of commercial banks.

scholarly journals Conspecific sperm precedence is reinforced, but postcopulatory sexual selection weakened, in sympatric populations of Drosophila

2019 ◽  
Vol 286 (1899) ◽  
pp. 20182535 ◽  
Author(s):  
Dean M. Castillo ◽  
Leonie C. Moyle
Keyword(s):  
Sexual Selection ◽  
Reproductive Isolation ◽  
Competitive Ability ◽  
Reproductive Traits ◽  
Sister Species ◽  
Direct Selection ◽  
Sympatric Populations ◽  
Collateral Effect ◽  
Selection For ◽  
The Cost

Sexual selection can accelerate speciation by driving the evolution of reproductive isolation, but forces driving speciation could also reciprocally feedback on sexual selection. This might be particularly important in the context of ‘reinforcement’, where selection acts directly to increase prezygotic barriers to reduce the cost of heterospecific matings. Using assays of sperm competition within and between two sister species, we show a signature of reinforcement where these species interact: populations of Drosophila pseudoobscura that co-occur with sister species D. persimilis have an elevated ability to outcompete heterospecific sperm, consistent with selection for increased postcopulatory isolation. We also find these D. pseudoobscura populations have decreased sperm competitive ability against conspecifics, reducing the opportunity for sexual selection within these populations. Our findings demonstrate that direct selection to increase reproductive isolation against other species can compromise the efficacy of sexual selection within species, a collateral effect of reproductive traits responding to heterospecific interactions.

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