• Overdominance is a rare condition in genetics where the phenotype of the heterozygote lies outside of the phenotypical range of both homozygote parents, and heterozygous individuals have a higher fitness than homozygous individuals. (wikipedia.org)
  • Evolution then approaches a population state where every phenotype has maximum viability in one of the two patches. (iiasa.ac.at)
  • In the case of a housekeeping gene, however, the evolutionary dynamical system approaches a population state where the heterozygote and only one homozygote phenotype are equivalent to the optimum phenotypes in the two patches. (iiasa.ac.at)
  • The chromosomal translocation generates a translocation-bearing altered insect population, the translocation-bearing altered insect population comprises translocation-bearing individuals that are translocation heterozygotes and translocation-bearing individuals that are translocation homozygotes for the chromosomal translocation, and the translocation-bearing individuals display a fitness that is greater than that of the wildtype (non-translocation-bearing) individuals when challenged in a condition in which a translocation-based drive occurs. (justia.com)
  • Heterozygotes for major chromosomal rearrangements such as fusions and fissions are expected to display a high level of sterility due to problems during meiosis. (frontiersin.org)
  • Therefore we studied the relation between heterozygote frequency and fertility rates, disregarding the characterization for incidence of malaria. (indexarticles.com)
  • The aims of this study are to test the hypothesis that differential fertility is a selection-induced mechanism that maintains balanced polymorphisms and to investigate the reasons for and the effects on reproduction of the incomplete correspondence of heterozygote frequency and malarial morbidity levels on Sardinia. (indexarticles.com)
  • Allele polymorphisms at loci in the MHC and locus are thought to be managed by balancing selection, either by overdominance (heterozygotes have a higher fitness than homozygotes) or by frequency dependent selection (rare alleles are at a selective advantage, but become disadvantageous when common) (4, 6, 7). (liveconscience.com)
  • 1975), have concentrated on revealing a high frequency of heterozygotes for thalassemia and G6PD deficiency in areas of past malaria morbidity. (indexarticles.com)
  • A sample of Sardinian villages is classified according to the estimates of heterozygote frequency obtained by Siniscalco et al. (indexarticles.com)
  • Polymorphism can be maintained by selection favoring the heterozygote, and this mechanism is used to explain the occurrence of some kinds of genetic variability. (wikipedia.org)
  • In a classic study on the ebony mutation, Kalmus demonstrated how polymorphism can persist in a population through heterozygote advantage. (wikipedia.org)
  • Previous research, comparing measures of dominance, overdominance and epistasis (mostly in plants), found that the majority of cases of heterozygote advantage were due to complementation (or dominance), the masking of deleterious recessive alleles by wild-type alleles, as discussed in the articles Heterosis and Complementation (genetics), but there were also findings of overdominance, especially in rice. (wikipedia.org)
  • The homozygote wild type was perfectly healthy, but did not possess the improved viability of the heterozygote, and was thus at a disadvantage compared to the heterozygote in survival and reproduction. (wikipedia.org)
  • We found that after adjusting for other covariates, NSCLC patients who smoked and who respectively had CG, CT, and TC heterozygotes of HMGB1 rs2249825, rs1045411, and rs1360485, were at lower risk of developing mutant EGFR , compared to those patients with wild-type homozygotes. (jcancer.org)
  • Loci exhibiting heterozygote advantage are a small minority of loci. (wikipedia.org)
  • The specific case of heterozygote advantage due to a single locus is known as overdominance. (wikipedia.org)
  • A well-established case of heterozygote advantage is that of the gene involved in sickle cell anaemia. (wikipedia.org)
  • Heterozygote advantage is a major underlying mechanism for heterosis, or "hybrid vigor", which is the improved or increased function of any biological quality in a hybrid offspring. (wikipedia.org)
  • More recent research, however, has established that there is also an epigenetic contribution to heterozygote advantage, primarily as determined in plants, though also reported in mice. (wikipedia.org)
  • Cases of both homozygote and heterozygote advantage have been demonstrated in several organisms, including humans. (wikipedia.org)
  • The first experimental confirmation of heterozygote advantage was with Drosophila melanogaster, a fruit fly that has been a model organism for genetic research. (wikipedia.org)
  • This mutation, which at first glance appeared to be harmful, conferred enough of an advantage to heterozygotes to make it beneficial, so that it remained at dynamic equilibrium in the gene pool. (wikipedia.org)
  • Haldane's (1949) theory of a selective advantage of heterozygotes in the presence of malaria has been largely tested and confirmed, principally for the sickle cell gene and glucose-6-phosphate dehydrogenase (G6PD) deficiency, in areas where malaria is still endemic (Africa, tropical zones). (indexarticles.com)
  • However, the same mutation also conveyed advantages, providing improved viability for heterozygous individuals. (wikipedia.org)
  • A common example is the case where the heterozygote conveys both advantages and disadvantages, while both homozygotes convey a disadvantage. (wikipedia.org)
  • A heterozygote advantage describes the case in which the heterozygous genotype has a higher relative fitness than either the homozygous dominant or homozygous recessive genotype. (wikipedia.org)
  • Previous research, comparing measures of dominance, overdominance and epistasis (mostly in plants), found that the majority of cases of heterozygote advantage were due to complementation (or dominance), the masking of deleterious recessive alleles by wild-type alleles, as discussed in the articles Heterosis and Complementation (genetics), but there were also findings of overdominance, especially in rice. (wikipedia.org)
  • As a result a population can be considered to be a mosaic of different genotypes, only some of which can be directly seen in the phenotypes, but interactions will occur between recessive alleles hidden in heterozygotes, and there is a dynamic equilibrium between the different forms. (biotopics.co.uk)
  • The nonviable XX, YY and ZZ possibilities would mean 1 in 4 conceptions would end in miscarriage as is the case with humans when the 2 parents are heterozygotes for a recessive gene which is lethal as the homozygote. (stackexchange.com)
  • Meiotic drivers are selfish elements that bias their own transmission into more than half of the viable progeny produced by a driver+/driver- heterozygote. (geneconvenevi.org)
  • The homozygote wild type was perfectly healthy, but did not possess the improved viability of the heterozygote, and was thus at a disadvantage compared to the heterozygote in survival and reproduction. (wikipedia.org)
  • However, while a diverse range of fitness costs are reported in the field, they are typically represented as a fixed reduction in survival or viability which is insensitive to ecological conditions such as competition. (ox.ac.uk)