Explore BrainMass

Predicting the inheritance of an X-linked trait

Mom Smith is heterozygous for an X-linked trait that can be recognized by a polymorphism when her DNA is cut with Hae III and probed with ExTend probe. The polymorphism is a 3.5kb band for normal and a 1.5kb band for disease. Please diagram what you predict the autoradiograph would look like for the above samples if the Smith sons 1 and 4 are affected and Smith Dad, Mom Jones and Dad Jones are not affected.
1 2 3 4 5 6 7 8 9 10 11 12

-Is the Smith daughter a carrier? Explain.
-What if Dad Jones is also affected but not Mom Jones or Dad Smith?
1 2 3 4 5 6 7 8 9 10 11 12

Solution Preview

X-linked polymorphism are carried on the X chromosomes. This means that they will have a sex-specific distribution. Females have two copies so they can be homozygous unaffected, heterozygous carriers, or homozygous affected. Males only have one X chromosome so they can either be unaffected wiht one copy of the unaffected polymorphism or affected with one copy of the affected polymorphism. Males can never be carriers or heterozygous for the polymorphism because they only have one X chromosome

The possible banding ...

Solution Summary

Detailed answer to questions regarding predicting the inheritance pattern of an X-linked trait and predicting the autoradiograph produced during genetic testing.