2. (6 points) Angelman Syndrome is caused by a mutation in a paternally imprinte
ID: 101971 • Letter: 2
Question
2. (6 points) Angelman Syndrome is caused by a mutation in a paternally imprinted gene. Answer the following questions about this condition (2 points each)
A. If a female is heterozygous for the mutation in the imprinted gene will she have the disorder or not? Explain
B. Suppose a spontaneous mutation occurs in the gene responsible for Angelman syndrome in the gametes of a male. He does not have the disorder himself because the genes in the rest of his cells are normal. But if he passes the mutation along to his daughter, will she have the syndrome? Explain your answer.
C. Suppose his daughter has the mutant allele and suppose she passes it on to both a daughter and a son. Which of these children, if any, will have the syndrome and why?
I was wondering for question B, how does the male have the mutant allele, this is paternal imprinting so his gametes will have silenced allele and from mother it will have normal allele, but is this how we approach this question? Thanks
Explanation / Answer
A. An individual usually has one active copy of an imprinted gene. It can transfer from either mother or parent. In a research, scientists found that the mutation in heterozygous imprinted gene is sufficient to create a pathologic phenotype and show diminished expression. The heterozygous mutation will also cause the disorder because imprinted allele mutation will not imprint in that female. Then, the gene will express the protein with the imprinting of the mother’s allele in that gene.
B. The imprinted gene mutations are usually dominant because they have only one copy from a single parent. In the mutation in the imprinted gene, will not possible to imprint by the cells of the person. However, in the case of paternal imprinted gene mutation, through the spontaneous mutation, the gene will not function. If the paternal trait inherits to the daughter, she would have no disorder because the gene from the father would not function and only daughter’s female version will express.
C. No children would have the disorder because if the boy gets it from the mother, he would have the functional copy of father gene. However, in the female the case would same as B.
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