Genetics Ch. 14
Pedigree Practice
Shown below is a pedigree chart for the inheritance of achondroplasia (ay-kon-druh-playzhuh), a form of dwarfism. Examine the pedigree chart, and answer the following
questions.
1. Using D to represent the dominant allele and d to represent the recessive allele,
determine the genotypes of the indicated (numbered) individuals. Record your
answers next to the circle/rectangle below. Hint: Start by indicating the
genotypes of 2, 3, and 7. Next, determine the genotypes of 1 and 4 and then
individuals 5 and 6.
2. Is the allele that causes this form of dwarfism recessive or dominant?
How do you know?
3. If the couple (individuals 5 and 6) were to have another child, what is the
probability that the child will have Achondroplasia? Explain.
4. If this condition were genetic, what might it indicate if you saw many more boys
with this condition than girls? Hint: on which chromosome might the gene be
found?
Biology
modified 2/17/2016