University:
University of Virginia
Course:
BIOL 1040 | The DNA Revolution in Science and Society
Academic year:

2024
Views:

55

Pages:

2
Author:

Kayli N.

Inheritance and Heritability Simple Traits: eye color, taste, rare genetic diseases (influenced by few loci/genes) Complex Traits: height, diabetes (influenced by many genes, informed by genomics in future) ● Can't divide into discrete classes due to overlapping and continuous distribution ○ Ex. Height, can’t call someone tall or short without having a relative comparison ● As we increase the number of genes involved, the number of possible genotypes/combinations increases which creates more distribution so more difficult to put into classes (more options) ○ Random gamete combinations (punnet squares) ○ Environmental influences results in a continuous solution ○ Phenotypic variance is influenced by ■ Genetic effects (nature) ■ Environmental Effects (nurture) ■ And many other complications Heritability: proportion of observed phenotypic variation that is genetic V(V+V) ● ● ● ● ● ● We measure this by More closely related to siblings by genetic similarity, all somewhat related Genetic variation/heritability is not fixed in a population If heribility was 1.0 gives a correlation under environmental conditions If herbibility was 0.0 gives no correlation Natural selection of genetic variation for evolution (ex. big beaks for finch birds) ● Twin Studies: Mono(identical) share most of genes and dizygotic(fraternal) twins that share 50% genes: slopes differ so Mono has higher ○ 50% environmental / genetics under experimental conditions ○ Can conduct surveys to see whether the answers are more similar to mono/di and calculate, also blood pressure etc. ● Risk of heart attack: determined by genetics and lifestyle placed into risk categories ○ Even if genetic determinism, the behavior of the person can affect outcome Take Home messages - Genetic variation (genotype) is essential for studying the underlying genetics of traits (phenotypes) For one or two loci, alleles may contribute additively to the phenotype, or there may be dominance. For many loci, genetic variation produces continuously variable traits. The genetic basis of traits is also complicated by environmental influences. Heritability is virtually never 0.0 or 1.0; phenotypes are rarely influenced purely by genetics or the environment. Heritability is traditionally measured by patterns of resemblance among relatives (parents/offspring, monozygotic versus dizygotic twins) Twin studies show high heritability for a large number of interesting human traits. Are all these traits real? What does it mean that political affiliations have high heritability? We will return to this point.

Inheritance and Heritability

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