Heterozygosity and Genetic Variation

The video discusses the concept of heterozygote advantage, where individuals with two different alleles for a gene have a survival benefit. This is a key mechanism for hybrid vigor, enhancing biological qualities in offspring. The video uses cystic fibrosis as an example, explaining how carriers of the CFTR mutation are less susceptible to diseases like cholera. The concept of polymorphism is also covered, highlighting how genetic variation is maintained in populations through selection favoring heterozygotes.

What is the term for when an individual has two different alleles for a gene?

• Recessive

• Homozygous

• Dominant

• Heterozygous

Which type of allele requires only one copy to express a trait?

• Heterozygous

• Dominant

• Homozygous

• Recessive

What is a major mechanism for hybrid vigor?

• Homozygote advantage

• Heterozygote advantage

• Genetic drift

• Natural selection

Which genetic disease is used as an example of heterozygote advantage?

• Sickle cell anemia

• Huntington's disease

• Cystic fibrosis

• Tay-Sachs disease

How does the CFTR mutation provide an advantage against cholera?

• By blocking infection

• By enhancing immune response

• By reducing fluid loss

• By increasing fluid secretion

What happens to mice with the CFTR mutation when infected with cholera?

• They develop cystic fibrosis

• They do not succumb to dehydration

• They have increased chloride channels

• They succumb to dehydration

What is the role of heterozygosity in population genetics?

• It favors homozygous individuals

• It eliminates recessive alleles

• It maintains genetic variability

• It reduces genetic variability

What is polymorphism in the context of genetics?

• The mutation of alleles

• The dominance of one allele over another

• The occurrence of two or more clearly defined types

• The occurrence of a single allele type

Why is having both alleles important for a population?

• It ensures uniformity

• It increases genetic variation

• It decreases mutation rates

• It promotes homozygosity

Which of the following is NOT a benefit of heterozygosity?

• Hybrid vigor

• Increased genetic variation

• Improved disease resistance

• Reduced genetic diversity