Chapter 10, Problem 29P

You have identified a SNP marker that in one large family shows no recombination with the locus causing a rare hereditary autosomal dominant disease. Furthermore, you discover that all afflicted individuals in the family have a G base at this SNP on their mutant chromosomes, while all wild-type chromosomes have a T base at this SNP. You would like to think that you have discovered the disease locus and the causative mutation but realize you need to consider other possibilities.

a.

What is another possible interpretation of the results?

b.

How would you go about obtaining additional genetic information that could support or eliminate your hypothesis that the base-pair difference is responsible for the disease? Problems 33 and 34 show that you can make predictions about a child’s genotype by genotyping linked markers even if you don’t directly examine the disease-causing mutation. This method can be valuable for diseases showing high allelic heterogeneity if the linkage is extremely tight.