Menu Close

What are quantitative traits controlled by?

What are quantitative traits controlled by?

This phenomenon has been explained as a quantitative trait is controlled by numerous genes, with each gene having relatively small effect, and readily affected by environments. Therefore, quantitative traits are also known as polygenic traits.

How quantitative traits are genetically controlled?

Many human phenotypes such as IQ, learning ability and blood pressure also are quantitative traits. These traits are controlled by multiple genes, each segregating according to Mendel’s laws. These traits can also be affected by the environment to varying degrees.

What influences variation in a quantitative trait?

Variation in a quantitative trait usually results from the contributions of multiple genes with small effects modified by environmental influences. The log of the ratio of the likelihood of the data with a major gene is compared with the likelihood of the data when there is no major gene modeled at that location.

What is quantitative variation?

variation measured on a continuum (eg height in human beings) rather than in discrete units or categories. See continuous variation. The existence of a range of phenotypes for a specific character, differing by degree rather than by distinct Qualitative differences.

What are examples of quantitative traits?

A quantitative trait is a measurable phenotype that depends on the cumulative actions of many genes and the environment. These traits can vary among individuals, over a range, to produce a continuous distribution of phenotypes. Examples include height, weight and blood pressure.

Is eye color a quantitative trait?

For example, carrying two recessive genes for eye color would refer to the genes that determine eye color. A quantitative trait is the term for specific characteristics that are determined by multiple genes as well as environmental factors. Quantitative traits are phenotypes that are controlled by multiple genes.

How many phenotypes will be there in 2 gene quantitative?

As you know, if the allelic interactions known for a particular gene the genotype can be used to predict the phenotype. With one gene controlling a trait we have three possible genotypes, AA, Aa and aa and depending on the allelic interactions (dominance or incomplete dominance) we can have two or three phenotypes.

What is true concerning a quantitative trait?

What is true concerning a quantitative trait? as the number of genes controlling a trait increases and the influence of environment variation becomes greater, there is a blurring of discreteness.

What is an example of quantitative variation?

What is quantitative inheritance?

quantitative inheritance The inheritance of a character (known as a quantitative character or trait) that depends upon the cumulative action of many genes, each of which produces only a small effect.

How do you identify a quantitative trait?

QTLs are mapped by identifying which molecular markers (such as SNPs or AFLPs) correlate with an observed trait. This is often an early step in identifying and sequencing the actual genes that cause the trait variation.

What are examples of quantitative traits in humans?

What causes continuous variation in a quantitative trait?

Such distributions are typical of quantitative traits. Some of the variation can be explained by differences in diet and perhaps other factors in the environment. Environment alone is not, however, sufficient to explain the full range of heights or weights.

Which is an example of a quantitative variation?

Quantitative characters like height, weight and intelligence in man, meat in animals, milk in cattle, all show these variations. These small quantitative variations could not be accounted for by distinct genes because they produced gradations in phenotypes that appeared to be continuous.

How is the occurrence of continuous variation in a population explained?

So the occurrence of continuous variation of a trait in a population can be explained by assuming it is controlled by several pairs of genes — called quantitative trait loci(QTL) — the effects of which are added together. This is called polygenic inheritanceor the multiple-factor hypothesis.

How are genes used to control quantitative traits?

An understanding of how genes can control quantitative traits emerged in 1908 from the work of the Swedish geneticist Nilsson-Ehle who studied quantitative traits in wheat. Using Mendel’s methods, he mated pure-breeding red-kernel strains with pure-breeding white-kernel strains.