overdominance การใช้

• There is little statistical evidence for contributions from overdominance and epistasis.
• Dominance and overdominance have different consequences for the gene expression profile of the individuals.
• Only a few conclusive cases of overdominance have been reported in all of genetics.
• Another mechanism responsible for inbreeding depression is the fitness advantage of heterozygosity, which is known as overdominance.
• Population geneticist James Crow believed, in his younger days, that overdominance was a major contributor to hybrid vigor.
• But whether the best hybrids are getting an extra boost from overdominance or favorable epistatic contributions remains an open question ."
• According to Crow, the demonstration of several cases of heterozygote advantage in Drosophila and other organisms first caused great enthusiasm for the overdominance theory among scientists studying plant hybridization.
• Since the early 1900s ( as discussed in the article Dominance versus overdominance ) two competing genetic hypotheses, not necessarily mutually exclusive, have been developed to explain hybrid vigor.
• Inbreeding depression caused by overdominance cannot be purged, but seems to be a minor cause of overall inbreeding depression, although its actual importance is still a matter of debate.
• Hubby and Lewontin also ruled out heterozygote advantage as the main cause because of the segregation load it would entail, though critics argued that the findings actually fit well with overdominance hypothesis.
• But overdominance implies that yields on an inbred strain should decrease as inbred strains are selected for the performance of their hybrid crosses, as the proportion of harmful recessives in the inbred population rises.
• The genetic "'overdominance hypothesis "'states that some combinations of alleles ( which can be obtained by crossing two inbred strains ) are especially advantageous when paired in a heterozygous individual.
• In addition, part of the inbreeding depression could not be due to deleterious alleles, but to an intrinsic advantage of being heterozygous compared to being homozygous for any available allele, which is known as overdominance.
• Bruce Wallace, working with J . C . King, used the " overdominance hypothesis " to develop the " balance position ", which left a larger place for overdominance ( where the heterozygous state of a gene is more fit than the homozygous states ).
• Bruce Wallace, working with J . C . King, used the " overdominance hypothesis " to develop the " balance position ", which left a larger place for overdominance ( where the heterozygous state of a gene is more fit than the homozygous states ).
• However, this result only holds for the " neutral " case, and is not necessarily true for the case when some alleles are subject to fit than others, for example when the fittest genotype is a heterozygote ( a situation often referred to as overdominance or heterosis ).
• 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 . though also reported in mice.
• 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 . though also reported in mice.