Name: The Reasons for Mendel's Success
Uploaded: 2019-07-19
Duration: 4 min 14 s
Description: The main reason for the success of Mendel was that he took one character at a time in his hybridization experiments. Watch this video to learn more.

Question

Explain polygenic inheritance and multiple allelism with the help of suitable examples.

Accepted Answer

A polygenic inheritance or quantitative inheritance is a type of inheritance of a single phenotypic trait is controlled by two or more different genes. Example - Human skin colour is an example of polygenic inheritance.

A, B and C are the dominant allele that encodes for Melanin pigment which is responsible for dark pigmentation. a, b and c are the recessive alleles that control the light colour pigmentation. If a person has all the dominant alleles(AABBCC), then the amount of melanin will be maximum and the skin will be dark. If a person has all the recessive alleles (aabbcc), then the amount of melanin will be lowest and the skin will be light. As the number of dominant alleles reduces the skin colour changed from dark to lighter shade. Thus, the various combinations of the dominant and recessive allele leads to the different colour of skin.

Multiple allelism - When a gene has more than two alleles on the same locus in a population, it is called multiple allelism. Example of multiple allelism is the human blood group. Three alleles, I^A, I^B and i, are responsible for different blood group.

I^AI^Aand I^Ai codes for A blood group
I^BI^Band I^Bi codes for B blood group
ii codes for O blood group
I^AI^Bcodes for AB blood group.

Explain polygenic inheritance and multiple allelism with the help of suitable examples.

Important Questions on Principles of Inheritance and Variations

Learn and Prepare for any exam you want !