Natural Selection Can Maintain Genetic Variation by Favoring Heterozygous Genotypes

question 26

Essay

Natural selection can maintain genetic variation by favoring heterozygous genotypes.In equatorial Africa,the best genotype to have for hemoglobin is heterozygous (HbA / HbS).In the United States,there is no advantage to the heterozygous genotype.HbA codes for normal hemoglobin,whereas HbS codes for abnormal hemoglobin that causes red blood cells to become distorted in shape (sickle cell).Explain why the heterozygous state is advantageous in Africa,but not in the United States.What has happened to the sickle-cell allele in Africa? What has happened to the sickle-cell allele in the United States?

---

Definitions:

CD-R

A type of compact disc that allows users to write data on it only once, making it a non-rewritable storage medium.

DVD-R

A type of digital versatile disc that allows users to record data once and read many times, used for storing media and data files.

Virtual Private Network

A service that creates a secure, encrypted connection over the internet from a device to a network, ensuring data confidentiality.

Public Telephone Lines

Communication lines provided by service providers that are accessible to the public for telecommunications, including telephone and internet services.