Imagine that you are searching for the gene associated with nail-patella syndrome,a dominant genetic disorder that causes developmental abnormalities.In a large pedigree you discover an association between nail-patella syndrome and a genetic marker that occurs in two different alleles,A and B.Fifteen individuals within this pedigree have nail-patella syndrome and are A/B heterozygotes for the marker.Thirty individuals within this pedigree don't suffer from nail-patella syndrome and are homozygous for the A marker allele.One individual within this pedigree has nail-patella syndrome and is also homozygous for the A marker allele.The most likely explanation for this exceptional individual is _____.
A)a new mutation converted the disease-causing allele to the wild-type form
B)a new mutation converted the B allele of the marker to the A form
C)the exceptional nail-patella individual is haploid
D)recombination occurred between the nail-patella gene and marker gene in one of the parents of the exceptional individual

Question

Quizplus · Accepted Answer

The exceptional individual has nail-patella syndrome and is homozygous for the A marker allele, which suggests that recombination occurred between the nail-patella gene and the marker gene in one of their parents. This results in the exceptional individual inheriting two copies of the A marker allele without also inheriting the nail-patella causing allele from that parent.

Imagine That You Are Searching for the Gene Associated with Nail-Patella