Monohybrid Cross with X-Linked Dominant Trait
- Fragile-X Syndrome is a genetic disorder that can lead to mental developmental issues, and has been
associated with symptoms of Autism Spectrum Disorder. It is an X-linked Dominant trait.
Assume a Father with Asperger’s (a mild form of Autism) has Fragile-X Syndrome. However, he is well adjusted
and is able to get married and start a family. He marries a woman who does not have Fragile-X syndrome, and
also has no family history of the disorder.
What is the Father’s genotype?
What is the Mother’s genotype?
Draw a Pu nnet square to determine the possible incidence rate of Fragile-X syndrome in their children.
What percent of children will have Fragile-X trait?
What percent of Male children will have Fragile-X trait?
What percent of Female children will have Fragile-X trait? - Using the same information from the question above, assume a woman with Fragile-X syndrome starts a
family with an unaffected man with no family history.
What is the Father’s genotype?
What is the Mother’s genotype?
Assuming the mother is Heterozygous, draw a Punnet square to determine the possible incidence rate of
Fragile-X syndrome in their children.
What percent of children will have Fragile-X trait?
What percent of Male children will have Fragile-X trait?
What percent of Female children will have Fragile-X trait?
Are the percentages different between questions 20 and 21? Why? _ _ _