Which one of the following pairs of features is a good example of polygenic inheritance?

Options

A. human heigh and skin colour
B. ABO blood group in humans and flower oclour of Mirabils jalapa
C. hair pigments of mouse and tounge rolling in humans
D. human eye colour and stickle cell anaemia

Answer

a

Explanation

Polygenic inheritance in the inheritance pattern of a trait controlled by two or moare genes. Genes may be on the same or different chromosomes and each gene may have two or more alleles. The gene expression is influenced by a variety of a factors including gender, nutrition, breed rate of grwoth, and amount of exercies. These traitsare quantitative traits- that is there is a wide range within, the population. Wuch traits include heights, weight. character. working abilities, and some genetic defects.
One example is heights in humans- three are a larger number of phenotypes, each differing slighlty from teh next and forming a graduated series. Some variation in height in humans is due to environmental factors such as diet, exrcise and disease. Howerver if the enviroment factros were constant, there would still be continuous variatin in hiehgt due to such things formationand hormone levels. The more genes that control a characteristic the more possible gene cominations eist and the more phenotypes.
Other examples of plygeneic inheritance include: skin colour in humans colour in wheat kernels, egg weiht, in poultry, flees weights in sheep. Kernal colour in wheat is determined bytwo gene pairs so called polygenes that produce a range of colors from white to dark red depending ont he combinations of alleles. Dark red plants are homozygous. AABB and white plants are homozygous aabb. When these homozygotes are crossed the `F_(1)` offspring are all double heterozygotes AaBb. Thus crossing individuals with the phenotype extremes yield offspring that are a blend of the two parents.