Home
Class 12
BIOLOGY
It is said, that the harmful alleles get...

It is said, that the harmful alleles get eliminated from population over a period of time, yet sickle-cell anaemia is persisting in human population. Why?

A

it is controlled by res:essive genes

B

it is not a fatal disease

C

it provides immunity against malaria

D

it is controlled by dominant genes

Text Solution

Verified by Experts

The correct Answer is:
C
Sickle-cell anaemia (in which RBCs become sickle-shaped and stiff) is a genetic disorder that is autosomal and linked to a recessive allele. It has not been eliminated from the African population because it provides immunity against malaria. People who are heterozygous for sickle cell allele are much less susceptible for falciparum malaria which is one of the main causes of illness and death in them. Thus, the sickle cell allele is maintained at high levels in populations where falciparum malaria is common.
Promotional Banner

Similar Questions

Explore conceptually related problems

How would you account for the occurrence of sickle-cell anaemia in human population?

Where would the greatest number of endemic species occur and why ? (a) Small volcanic archipelagos, such as the Galapagos Islands, because the abundance of unoccupied habitats favours the adaptive divergence of colonists from nearby mainland populations. (b) Large oceanic island, such as Australia, because the inhabitants have been isolated from mainland populations for a very long time. (c) On rugged landscapes, such as Patagonia, because of the high levels of natural disturbance by glaciers and earthquakes. (d) Temperate woodlands, such as those in southern England, because of the high levels of disturbance by human activity and the history of artificial selection.

Fill up the balnks in the following paragraph by selecting the correct option. When migration of a section of population to another place and population occurs, I change in the original as well as in the new population new genes/ alleles are added to the ii, population and these are lost from the population. These would be a iv if this gene migration, happens multiple times. if the same change occurs by chance, it is called v. sometimes the change in allele frequency is so different in the new sample of population that they become a diffrent species. The original drifted population becomes founders and the effect is called vi