Human Genetics: Test Your Understanding
+
ward
'
s
science
Compare the number of chromosomes in a normal human body cell with the number of chromosomes
in a normal human reproductive cell.
A normal human body cell is diploid and contains 46 chromosomes, and a normal human reproductive
cell is haploid and contains 23 chromosomes.
If a male hemophiliac has a child with a female carrier, is there a possibility that their son will be a
hemophiliac? Is there a possibility their daughter will be a hemophiliac? Explain your answer.
Yes. Because the mother is a carrier, a child born in this situation has a 50% chance of receiving
the mutant allele on the X chromosome. Both a son or a daughter will be a hemophiliac if he or she
receives the hemophilia allele from the mother.
Critical Thinking: Why are conservation biologists concerned with genetic drift?
Conservation biologists often study small populations of plant or animal species. Small populations
have a greater chance of genetic drift than larger populations. If too much diversity is lost through
genetic drift, the population might not survive.
~ Continued ~
