Question

Human height is a multi genetic character. If the Heights of all the individuals living in a metropolis are measured and the percentages of the population belonging to a specific height are plotted as shown. Which of the plots would represent the most realistic distribution?

A. P
B. Q
C. R
D. S

Answer 1

Hint: If one characteristic of a person is controlled by one or more gene, it is said to be a polygenic inheritance, in these types, the quantity of genes are more but the effect is small, some of the examples of the polygenetic or multi genetic inheritance is height, color, etc.

Complete answer:
Main properties of multi genetic inheritance is
- Most of the metric and meristic traits are controlled by a number of gene locus.
- Non Allelic gene interaction is based on the corresponding gene series and their linkage to some other genes.
- The phenotypic expression of the multi genetic characteristic is not the same ; sometimes it is influenced by the environmental stimulus.
- Multi Genetic characteristics show the continuous distribution rather than discontinuous.
- In these types of traits, generally the frequency of phenotypes are normal continuous variation, distribution pattern.
- In this type, a lot of genes are involved, where it produces the bell shaped curve.
- More the genes involved in this type of inheritance, smoother the curve that is obtained.
- This mode of distribution represent the optimal or fittest phenotypes
- So from the above explanation, in case of multi genetic inheritance, the graph which forms is bell shaped curve.

Hence, the correct answer is option (A).

Note: In multiple genetic characteristics, all genes code for the alleles with additive effects, sometimes many genes show the epistasis effect, which can have unpredictable effects on the distribution of outcome.