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Polygenic Inheritance MCQ - Practice Questions with Answers
Edited By admin | Updated on Sep 18, 2023 18:34 AM | #NEET
Quick Facts
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Polygenic Inheritance is considered one the most difficult concept.
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9 Questions around this concept.
Solve by difficulty
MEDIUMIf a plant has a genotype AABbCC, how many different types of gametes can be produced?
A dihybrid ratio of 1 : 4 : 6 : 4 : 1 is obtained instead of 9 : 3 : 3 : 1. This is an example of
How does the number of alleles in a genotype affect skin color in humans?
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Concepts Covered - 1
Polygenic Inheritance
- Mendel’s studies mainly described those traits that have distinct alternate forms such as flower colour which are either purple or white.
- However, there are some human characteristics, such as height, eye color, and hair color, that don't come in just a few distinct forms.
- Instead, they vary in small gradations, forming a spectrum or continuum of possible phenotypes.
- Features like these are called quantitative characters, and they’re typically controlled by multiple genes (often, many genes), each of which contributes to the overall phenotype.
- For example, in humans we don’t just have tall or short people as two distinct alternatives but a whole range of possible heights.
- Besides the involvement of multiple genes polygenic inheritance also takes into account the influence of environment.
- Human skin colour is another classic example for this.
- In a polygenic trait the phenotype reflects the contribution of each allele, i.e., the effect of each allele is additive.
- To understand this better let us assume that three genes A, B, C control skin colour in humans with the dominant forms A, B and C responsible for dark skin colour and the recessive forms a, b and c for light skin colour.
- The genotype with all the dominant alleles (AABBCC) will have the darkest skin colour and that with all the recessive alleles (aabbcc) will have the lightest skin colour.
- As expected the genotype with three dominant alleles and three recessive alleles will have an intermediate skin colour.
- In this manner the number of each type of alleles in the genotype would determine the darkness or lightness of the skin in an individual.
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