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 ?
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 ?
The harmful alleles get eliminated from population over a period of time, yet sickle cell anaemia is persisting in human population because $SCA$ is a harmful condition which is also a potential saviour from malaria. Those with the benign sickle trait possess a resistance to malarial infection. The pathogen that causes the disease spends part of its cycle in the red blood cells and triggers an abnormal drop in oxygen levels in the cell. In carriers, this drop is sufficient to trigger the full sicklecell reaction, which leads to infected cells being rapidly removed from circulation and strongly limiting the infection's progress.
These individuals have a great resistance to infection and have a greater chance of surviving outbreaks. This resistance to infection is the main reason the $SCA$ allele and $SCA$ disease still exist It is found in greatest frequency in populations where malaria was and often still is a serious problem
Similar Questions
Why is the frequency of red-green colour blindness is many times higher in males than that in the females ?
Why is the frequency of red-green colour blindness is many times higher in males than that in the females ?
If a haemophilic man marries a woman carrier (heterozygous) for haemophilia, what would be the possibility that their daughter would be haemophilic
If a haemophilic man marries a woman carrier (heterozygous) for haemophilia, what would be the possibility that their daughter would be haemophilic
Which of the following is an example of sex-linked disease?
Which of the following is an example of sex-linked disease?
:Match the columns :
Column $I$
Column $II$
$(1)$ Albinism
$(p)$ recessive gene
represented by
HbsHbs.
$(2)$ Phenyl
Ketonuria
$(q)$ recessive gene
represented by cc.
$(3)$ Sickle cell
anaemia
$(r)$ recessive gene
represented by aa.
$4)$ Alkaptonuria
$(s)$ recessive gene
represented by pp
:Match the columns :
| Column $I$ |
Column $II$ |
| $(1)$ Albinism | $(p)$ recessive gene represented by HbsHbs. |
| $(2)$ Phenyl Ketonuria |
$(q)$ recessive gene represented by cc. |
| $(3)$ Sickle cell anaemia |
$(r)$ recessive gene represented by aa. |
| $4)$ Alkaptonuria | $(s)$ recessive gene represented by pp |
Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the character.
Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the character.
- [AIPMT 2010]