People That Have a Single Allele (Gene Copy) for Sickle

question 27

Multiple Choice

People that have a single allele (gene copy) for sickle cell anemia are typically not sick from the disease and are said to be carriers of sickle cell trait. These people will more often live in the malaria belt of sub-Saharan Africa. The most likely explanation for this is_________ .

• A) sickle cell trait is passed on to the biting mosquitoes as malaria
• B) malaria is a cause of sickle cell trait
• C) people with sickle cell trait have a better chance of surviving malaria
• D) the tropical climate attracts people with sickle cell trait

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Definitions:

Heterozygous

Having inherited two genes of different allelic forms for a trait.

Dominant Allele

The allele that is expressed when an individual possesses two different alleles for the same trait.

Recessive Allele

The allele that is not expressed when an individual possesses two different alleles for the same trait.

Carriers

Individuals who are heterozygous for a trait with a dominant and recessive allele and thus express only the characteristics associated with the dominant allele but may pass the recessive allele, including one for a recessive disorder, on to their offspring.