It is expected that selection pressure should have eliminated the gene for sickle cell anaemia. How would you account for its continuancein human population?
Hi Santy,
Please find below the solution to the asked query:
In case of sickle cell anaemia, it has been found that homozygous individuals for the normal haemoglobin allele are easily affected by malaria as compared to the individuals who are heterozygous for the sickle cell gene. These heterozygous individuals are protected against malaria and do not get sickle cell disease.
The selection pressure for other factor actually favours the continuation of the sickle cell gene. The individuals who have inherited normal gene from one parent and sickle cell gene from other parent appear apparently unaffected or may show mild anaemia. These heterozygous individuals when exposed to malarial protozoan show resistance against malaria as compared to the individual who have normal genes. Thus, the organisms with heterozygous genes have an advantage when it comes to survival. Hence, malaria is a selective pressure that favours the continuation of sickle cell anaemia gene and occurs mainly in the regions where malaria is most prevalent.
Hope this information will clear your doubts about continuation of sickle cell gene.
If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.
Regards
Please find below the solution to the asked query:
In case of sickle cell anaemia, it has been found that homozygous individuals for the normal haemoglobin allele are easily affected by malaria as compared to the individuals who are heterozygous for the sickle cell gene. These heterozygous individuals are protected against malaria and do not get sickle cell disease.
The selection pressure for other factor actually favours the continuation of the sickle cell gene. The individuals who have inherited normal gene from one parent and sickle cell gene from other parent appear apparently unaffected or may show mild anaemia. These heterozygous individuals when exposed to malarial protozoan show resistance against malaria as compared to the individual who have normal genes. Thus, the organisms with heterozygous genes have an advantage when it comes to survival. Hence, malaria is a selective pressure that favours the continuation of sickle cell anaemia gene and occurs mainly in the regions where malaria is most prevalent.
Hope this information will clear your doubts about continuation of sickle cell gene.
If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.
Regards