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单词 heritability
释义
heritability

Statistics
  • The proportion of the variance of some population characteristic that is attributable to genetic variation. Often estimated using either the path analysis of Wright, or via ANOVA using a components of variance model.


Biology
  • A measure of the degree to which the variance of a particular phenotype is caused by genetic factors. It is given by a value between 0 and 1 and effectively measures the extent to which offspring resemble their parents relative to the population mean. Estimates of heritability are important in applied genetics, especially in agriculture and horticulture, because they enable prediction of the response of a population to artificial selection. The higher the heritability value, the greater the response, although heritability declines after several generations of artificial selection due to increasing homozygosity. The term is used in two different ways. Heritability in the narrow sense is the proportion of phenotypic variance due only to the additive genetic effect of all the polygenes controlling a particular trait; hence it measures the proportion that is transmissible to offspring and therefore amenable to selection. Heritability in the broad sense considers other genetic but nontransmissible factors as well, including dominance and epistasis; it is used, for example, in psychology to quantify genetic and environmental influences.


Philosophy
  • Widely misunderstood concept used in debates about nature versus nurture. The heritability of a trait in a population is the proportion of phenotypic variance (variance in some observable feature, whether of shape or size or behaviour) attributable to genetic variance. It is a measure that itself may vary with the range of genetic backgrounds and range of environments studied. For example, if all environmental factors are identical, any variation will have a genetic explanation, and heritability will approach 100%; but if genetic origin is kept constant and environment varied then heritability of the same trait may decrease towards 0%. It is therefore a mistake to argue from any particular high figure for heritability in some population in some environment, to a ‘genetic determinism’ or pessimism about the effects of environmental intervention.


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