scholarly journals During environmental change, cooperation can promote rescue or lead to evolutionary suicide

2019 ◽  
Author(s):  
Gil J. B. Henriques ◽  
Matthew M. Osmond
Keyword(s):  
Population Density ◽  
Population Size ◽  
Feedback Loop ◽  
Evolution Of Cooperation ◽  
Effective Population ◽  
Changing Environment ◽  
Slow Adaptation ◽  
Evolutionary Suicide ◽  
Time Changes ◽  
Lower Population

The adaptation of populations to changing conditions may be affected by interactions between individuals. For example, cooperative interactions may allow populations to maintain high densities, and thus keep track of moving environmental optima. At the same time, changes in population density alter the marginal benefits of cooperative investments, creating a feedback loop between population dynamics and the evolution of cooperation. Here we model how the evolution of cooperation is affected by, and in turn affects, adaptation to a changing environment. We hypothesize that changes in the environment lower population size and thus promote the evolution of cooperation, and that this in turn helps the population keep up with the moving optimum. However, we find that the evolution of cooperation can have qualitatively different effects, depending on which fitness component is reduced by the costs of cooperation. If the costs decrease fecundity, cooperation indeed speeds adaptation by increasing population density; if, in contrast, the costs decrease viability, cooperation may in fact slow adaptation by lowering the effective population size, leading to evolutionary suicide. Thus, we show that cooperation can either promote or—counter-intuitively—hinder adaptation to a changing environment.

scholarly journals Spread of new mutations through space

2022 ◽  
Author(s):  
Kyle Shaw ◽  
Peter Beerli
Keyword(s):  
Population Density ◽  
Population Size ◽  
Simulation Software ◽  
Effective Population ◽  
Random Drift ◽  
Rate Of Spread ◽  
Large Populations ◽  
Discrete Population ◽  
Explicit Simulation ◽  
New Mutations

The terms population size and population density are often used interchangeably, when in fact they are quite different. When viewed in a spatial landscape, density is defined as the number of individuals within a square unit of distance, while population size is simply the total count of a population. In discrete population genetics models, the effective population size is known to influence the interaction between selection and random drift with selection playing a larger role in large populations while random drift has more influence in smaller populations. Using a spatially explicit simulation software we investigate how population density affects the flow of new mutations through a geographical space. Using population density, selectional advantage, and dispersal distributions, a model is developed to predict the speed at which the new allele will travel, obtaining more accurate results than current diffusion approximations provide. We note that the rate at which a neutral mutation spreads begins to decay over time while the rate of spread of an advantageous allele remains constant. We also show that new advantageous mutations spread faster in dense populations.

scholarly journals Influência do tamanho e densidade populacional no rendimento esportivo da ginástica artística brasileira (Influence of population size and density on sports performance of Brazilian artistic gymnastics)

Retos ◽  
2019 ◽  
pp. 66-70
Author(s):  
Cristiano Israel Caetano ◽  
Rafael Gomes Sentone ◽  
José Francisco López-Gil ◽  
Hallyne Bergamini Silva Caetano ◽  
Fernando Renato Cavichiolli
Keyword(s):  
Logistic Regression ◽  
Population Density ◽  
Population Size ◽  
Public Policies ◽  
Influencing Factor ◽  
Binary Logistic Regression ◽  
Sports Performance ◽  
Performance Results ◽  
Lower Population ◽  
Lower Population Density

Resumo. A pesquisa investigou por intermédio do levantamento dos atletas federados da ginástica artística brasileira que participaram de ao menos um dos dois campeonatos nacionais (n=620), se o tamanho da população (estratificada em cinco categorias) é um fator que influenciam no sucesso esportivo, utilizando para tanto regressão logística binaria. Por segundo, utilizando o teste de Kruskall-Wallis, classificando o ranking de atletas em quartis buscou identificar se a densidade populacional é um fator de influência para ter rendimento esportivo. Os resultados indicam que no Brasil, pertencer a cidades maiores (100001 até 500000 habitantes) faz com que atletas possuam 7,51 vezes (IC95%=6.30-8.96) mais chances de ter resultados esportivos de rendimento, com destaque para os homens em cidades com densidade populacional mais baixa em comparação com as mulheres, sendo um possibilidade explorar a influência das políticas públicas de icentivo ao esporte nestas cidades.Abstract. The survey investigated through the survey of federated athletes of Brazilian artistic gymnastics who participated in at least one of the two national championships (n = 620), whether the population size (stratified into five categories) is a factor that influence the sporting success, using binary logistic regression. Second, using the Kruskall-Wallis test, ranking the ranking of athletes in quartiles sought to identify whether population density is an influencing factor for sports performance. The results indicate that in Brazil, belonging to larger cities (100001 to 500000 inhabitants) makes athletes have 7.51 times (95% CI = 6.30-8.96) more chances to have sportive performance results, especially men in cities. with a lower population density compared to women, and it is possible to explore the influence of sport-promoting public policies in these cities.

Evolutionary genetics of small populations

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Evolutionary Genetics ◽  
Small Population ◽  
Small Populations ◽  
Effective Population ◽  
Genetic Management ◽  
Evolutionary Genetic ◽  
Loss Of Genetic Diversity ◽  
Number Of Individuals

Genetic management of fragmented populations involves the application of evolutionary genetic theory and knowledge to alleviate problems due to inbreeding and loss of genetic diversity in small population fragments. Populations evolve through the effects of mutation, natural selection, chance (genetic drift) and gene flow (migration). Large outbreeding, sexually reproducing populations typically contain substantial genetic diversity, while small populations typically contain reduced levels. Genetic impacts of small population size on inbreeding, loss of genetic diversity and population differentiation are determined by the genetically effective population size, which is usually much smaller than the number of individuals.

scholarly journals A phylogenetic estimator of effective population size or mutation rate.

Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 685-692 ◽  
Author(s):  
Y X Fu
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Mutation Rate ◽  
Dna Sequences ◽  
High Efficiency ◽  
Minimum Variance ◽  
Population Subdivision ◽  
Effective Population ◽  
Fisher Model ◽  
Mitochondrial Sequences

Abstract A new estimator of the essential parameter theta = 4Ne mu from DNA polymorphism data is developed under the neutral Wright-Fisher model without recombination and population subdivision, where Ne is the effective population size and mu is the mutation rate per locus per generation. The new estimator has a variance only slightly larger than the minimum variance of all possible unbiased estimators of the parameter and is substantially smaller than that of any existing estimator. The high efficiency of the new estimator is achieved by making full use of phylogenetic information in a sample of DNA sequences from a population. An example of estimating theta by the new method is presented using the mitochondrial sequences from an American Indian population.

scholarly journals Harmful mutation load in the mitochondrial genomes of cattle breeds

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sankar Subramanian
Keyword(s):  
Population Size ◽  
Artificial Selection ◽  
Deleterious Mutation ◽  
Genetic Diseases ◽  
Mitochondrial Genomes ◽  
Deleterious Mutations ◽  
Founder Population ◽  
Mutation Load ◽  
Effective Population ◽  
Cattle Breeds

Abstract Objective Domestication of wild animals results in a reduction in the effective population size, and this could affect the deleterious mutation load of domesticated breeds. Furthermore, artificial selection will also contribute to the accumulation of deleterious mutations due to the increased rate of inbreeding among these animals. The process of domestication, founder population size, and artificial selection differ between cattle breeds, which could lead to a variation in their deleterious mutation loads. We investigated this using mitochondrial genome data from 364 animals belonging to 18 cattle breeds of the world. Results Our analysis revealed more than a fivefold difference in the deleterious mutation load among cattle breeds. We also observed a negative correlation between the breed age and the proportion of deleterious amino acid-changing polymorphisms. This suggests a proportionally higher deleterious SNPs in young breeds compared to older breeds. Our results highlight the magnitude of difference in the deleterious mutations present in the mitochondrial genomes of various breeds. The results of this study could be useful in predicting the rate of incidence of genetic diseases in different breeds.

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