A very interesting genetic case?

The pedigree below depicts a family from Bloomington that is affected by familial acrophobia. The frequency of affected individuals in the population at large is negligible - this is a very rare trait.





http://www.flickr.com/photos/26031843@N0...





a) Which modes of inheritance can definitely be excluded by the pedigree. For each one excluded, give your reasoning.


• Autosomal recessive:


• Autosomal dominant:


• X-linked recessive:


• X-linked dominant:


• Y-linked:


b) Which mode of inheritance is most likely and why?


c) Based on your answer to part b, give the genotype for each pedigree individual listed below. Define your symbols.


• III-5


• III-6


• IV-9


• IV-11


• V-9


d) Based on your answer to part b, if individual V-1 marries V-4, what is the probability that their first child will be affected? Would your answer be different for a first male child or a first female child? Why or why not?

A very interesting genetic case?
go to:


genetic.edu/students/bio188