نتایج جستجو برای: diploidy

تعداد نتایج: 6989  

Journal: :Interface focus 2013
Johan A J Metz Carolien G F de Kovel

One of the powerful tools of adaptive dynamics is its so-called canonical equation (CE), a differential equation describing how the prevailing trait vector changes over evolutionary time. The derivation of the CE is based on two simplifying assumptions, separation of population dynamical and mutational time scales and small mutational steps. (It may appear that these two conditions rarely go to...

Journal: :Genetics 1941
M M Lesley J W Lesley

VERY small tomato plant occurred in F1 from diploid dwarf dldl A parents, grown in the field at Riverside, California, for a study of male sterility. The mutant was very slow-growing, compared with normal sibs, but was perfectly developed and apparently healthy. It had extremely short internodes and very small leaves (fig. I). It flowered freely and produced very small yellow (ry) fruit in abun...

Journal: :Journal of evolutionary biology 2012
A Gardner

Maternal care has been suggested to evolve more readily in haplodiploid populations. Because maternal care appears to have been a prerequisite for the evolution of eusociality, this effect potentially explains the apparent preponderance of haplodiploidy among eusocial taxa. Here, I use a kin selection approach to model the evolution of maternal care in diploid and haplodiploid populations. In c...

Journal: :Journal of theoretical biology 1998
T Day P D Taylor

A framework is presented for unifying single locus genetic and game theoretic models of continuous traits under frequency-dependent selection when there are interactions among relatives. This framework serves two purposes. First, it is used to determine how "games between relatives" must be modeled to be genetically valid. There are two commonly employed phenotypic approaches used in this setti...

Journal: :Genetics 2001
P Donnelly M Nordborg P Joyce

Methods for simulating samples and sample statistics, under mutation-selection-drift equilibrium for a class of nonneutral population genetics models, and for evaluating the likelihood surface, in selection and mutation parameters, are developed and applied for observed data. The methods apply to large populations in settings in which selection is weak, in the sense that selection intensities, ...

Journal: :Journal of mathematical biology 2008
Christina T L Chen Quo-Shin Chi Stanley A Sawyer

We consider whether the fixation probability of an allele in a two-allele diploid system is always a monotonic function of the selective advantage of the allele. We show that while this conjecture is correct for intermediate dominance, it is not correct in general for either overdominant or underdominant alleles, and that for some parameter ranges the fixation probability can initially decrease...

Journal: :Journal of theoretical biology 2006
Y Bello D Waxman

We investigate a model that describes the evolution of a diploid sexual population in a changing environment. Individuals have discrete generations and are subject to selection on the phenotypic value of a quantitative trait, which is controlled by a finite number of bialleic loci. Environmental change is taken to lead to a uniformly changing optimal phenotypic value. The population continually...

Journal: :Genetics 2000
J R Chasnov

A leading hypothesis for the evolutionary function of sex postulates that sex is an adaptation that purges deleterious mutations from the genome, thereby increasing the equilibrium mean fitness of a sexual population relative to its asexual competitor. This hypothesis requires two necessary conditions: first, the mutation rate per genome must be of order one, and, second, multiple mutations wit...

Journal: :Molecular biology and evolution 1995
L Excoffier M Slatkin

Molecular techniques allow the survey of a large number of linked polymorphic loci in random samples from diploid populations. However, the gametic phase of haplotypes is usually unknown when diploid individuals are heterozygous at more than one locus. To overcome this difficulty, we implement an expectation-maximization (EM) algorithm leading to maximum-likelihood estimates of molecular haplot...

Journal: :Molecular phylogenetics and evolution 2015
Ray C Schmidt Henry L Bart

Phylogenies produced by Yang et al. 2015 provide reasonably well-supported hypotheses of relationships among 11 proposed tribes of cyprinine fishes and present an interesting hypothesis about the origin of a number of polyploid cyprinine lineages. However, support for relationships within some of the tribes is equivocal. Herein we address the treatment of African diploid and tetraploid cyprinin...

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