Pineapple skin in a condition indigenousness to the island of Hawaii. It is char
ID: 165738 • Letter: P
Question
Pineapple skin in a condition indigenousness to the island of Hawaii. It is characterized by rough patches of skin on the trunk and extremes. The genetic mutation that causes Pineapple skin is located on chromosome 4 and one copy of the mutation is to be affected. In a particular family, the grandfather did not exhibit symptoms until he was 63 years old and his grandfather started exhibiting symptoms at 4 years old. What type of inheritance is this? Anticipation Incomplete dominance Expressivity penetranceExplanation / Answer
Answer: Expressivity
Expressivity inheritance measures the extent to which a given genotype is expressed at the phenotypic level. Different degrees of expression in different individuals may be due to variation in the allelic constitution of the rest of the genome or to environmental factors.
So the disease was not expressed in case of the grandfather and was expressed in case of grandaughter.
In anticipation the disease become apparent at earlier age which did not happen in this case, for the grandaughter the symptoms came in age of 4 yrs.
In penetrance an allele of a gene that expresses the associated trait.Here the trait is not expressed.
It si also not a case of incomplete dominance,heterozygotes exhibit both alleles simultaneously.