Heritability is a measure of how well differences in people’s genes account for differences in their traits. Traits can include characteristics such as height, eye color, and intelligence, as well as disorders like schizophrenia and autism spectrum disorder. In scientific terms, heritability is a statistical concept (represented as h²) that describes how much of the variation in a given trait can be attributed to genetic variation. An estimate of the heritability of a trait is specific to one population in one environment, and it can change over time as circumstances change. Show
Heritability estimates range from zero to one. A heritability close to zero indicates that almost all of the variability in a trait among people is due to environmental factors, with very little influence from genetic differences. Characteristics such as religion or language spoken have a heritability of zero because they are not under genetic control. A heritability close to one indicates that almost all of the variability in a trait comes from genetic differences, with very little contribution from environmental factors. Many disorders that are caused by variants (also known as mutations) in single genes, such as phenylketonuria (PKU), have high heritability. Most complex traits in people, such as intelligence and multifactorial diseases, have a heritability somewhere in the middle, suggesting that their variability is due to a combination of genetic and environmental factors. Heritability has historically been estimated from studies of twins. Identical twins have almost no differences in their DNA, while fraternal twins share, on average, 50 percent of their DNA. If a trait appears to be more similar in identical twins than in fraternal twins (when they were raised together in the same environment), genetic factors likely play an important role in determining that trait. By comparing a trait in identical twins versus fraternal twins, researchers can calculate an estimate of its heritability. Heritability can be difficult to understand, so there are many misconceptions about what it can and cannot tell us about a given trait:
If heritability provides such limited information, why do researchers study it? Heritability is of particular interest in understanding traits that are very complex with many contributing factors. Heritability can give initial clues as to the relative influences of “nature” (genetics) and “nurture” (environment) on complex traits, and it can give researchers a place to start teasing apart the factors that influence these traits. Scientific articles for further readingMoore DS, Shenk D. The heritability fallacy. Wiley Interdiscip Rev Cogn Sci. 2017 Jan;8(1-2). doi: 10.1002/wcs.1400. Epub 2016 Dec 1. Review. PubMed: 27906501. Tenesa A, Haley CS. The heritability of human disease: estimation, uses and abuses. Nat Rev Genet. 2013 Feb;14(2):139-49. doi: 10.1038/nrg3377. Review. PubMed: 23329114.
Illustration to show the inheritance of dominant and recessive alleles for eye colour. What are sex-linked genes?
For example: Functioning allele = H Haemophilia allele = h XH XH = healthy female XH Xh = carrier female Xh Xh = haemophilia female XH Y = healthy male Xh Y = haemophilia male This page was last updated on 2021-07-21 What is the term used to refer to a trait which is determined by a combination of different alleles?Within an individual organism, the specific combination of alleles for a gene is known as the genotype of the organism, and (as mentioned above) the physical trait associated with that genotype is called the phenotype of the organism.
What is the term for a trait that is controlled by a combination of genes in addition to environmental influences quizlet?Multifactorial traits. are traits that are controlled by both genes and environmental influences. Some common polygenic multifactorial traits are height, skin color, hair color, body weight, many illnesses (including cancer), behavioral traits and tendencies.
Which term is used for a genetically determined characteristic?A trait, as related to genetics, is a specific characteristic of an individual. Traits can be determined by genes, environmental factors or by a combination of both.
Which term refers to the determination of an individual's traits through a combination of both genetic and environmental factors?Phenotype refers to an individual's observable traits, such as height, eye color and blood type. A person's phenotype is determined by both their genomic makeup (genotype) and environmental factors.
|