Pedigree Charts

 

Hemophilia, disease in which the blood lacks a clotting factor, is caused by an X linked recessive gene. Joe doe not have hemophilia and Lucille is heterozygous for the condition.  What is the chance that their MALE child will have hemophilia? (Note: you are calculating the probability for their MALE children only, in other words if they have 1 male child, what is the probability that he will be born with the disease?)

-0%

-1/4 or 25%

-2/4 or 50%

-3/4 or 75%

-4/4 or 100%

 

In humans, having facial dimples is dominant to not having facial dimples. Mary has dimples, yet only 3 of her 10 children have dimples.  What must Mary's genotype be?

-homozygous dominant

-heterozygous

-homozygous recessive

-has dimples

-does not have dimples

 

Red-green color blindness is an X-linked recessive disorder.  If Allison is heterozygous (a carrier), and her husband, Michael, is NOT colorblind. What is the chance that their male children will be colorblind? (Note: you are calculating the probability for their MALE children only, in other words if they have 1 male child, what is the probability that he will be born with the disease?)

-0%

-25% or 1/4

-50% or 2/4

-75% or 4/4

-100% or 4/4

 

Red-green color blindness is an X-linked recessive disorder. If Allison is heterozygous (a carrier), and her husband, Michael, is NOT colorblind. What is the chance that their female children will be colorblind? (Note: you are calculating the probability for their FEMALE children only, in other words if they have 1 female child, what is the probability that she will be born colorblind?)

-0%

-25% or 1/4

-50% or 2/4

-75% or 3/4

-100% or 4/4