GENETICS MAJORS ONLY PLEASE, AND DO NOT COPY THE LAST ANSWER GIVEN ON THIS SITE AS IT WAS INCORRECT!!!!!
Question: A mother is heterozygous for an over-expressed plastin allele on her X chromosome, thus has longer than normal axons. She is also heterozygous for the SMN1 gene on chromosome 5. Her childrenâs father is normal for plastin and has normal length axons. He too is heterozygous for the SMN1 gene. Both genes influence spinal muscular atrophy type 1 (SMA1); two abnormal copies of the SMN1 gene are required to cause spinal muscular atrophy, but their effect is prevented by high expression of the plastin gene (Lewis 92).
a) Give the genotypes of the mother and the father; provide a legend for your symbols. For each gene, explain why the abnormal alleles are dominant or recessive. (4 marks)
b) List all the possible genotypes and proportions of their offspring for the plastin gene. (1 mark)
c) List all the possible genotypes and proportions of their offspring for the SMN1 gene. (1 mark)
D) Showing your work, determine the probability that this couple will have a daughter with SMA. (2 marks)
e) Showing your work, determine the probability that this couple will have a son with SMA. (2 marks)
GENETICS MAJORS ONLY PLEASE, AND DO NOT COPY THE LAST ANSWER GIVEN ON THIS SITE AS IT WAS INCORRECT!!!!!
Question: A mother is heterozygous for an over-expressed plastin allele on her X chromosome, thus has longer than normal axons. She is also heterozygous for the SMN1 gene on chromosome 5. Her childrenâs father is normal for plastin and has normal length axons. He too is heterozygous for the SMN1 gene. Both genes influence spinal muscular atrophy type 1 (SMA1); two abnormal copies of the SMN1 gene are required to cause spinal muscular atrophy, but their effect is prevented by high expression of the plastin gene (Lewis 92).
a) Give the genotypes of the mother and the father; provide a legend for your symbols. For each gene, explain why the abnormal alleles are dominant or recessive. (4 marks)
b) List all the possible genotypes and proportions of their offspring for the plastin gene. (1 mark)
c) List all the possible genotypes and proportions of their offspring for the SMN1 gene. (1 mark)
D) Showing your work, determine the probability that this couple will have a daughter with SMA. (2 marks)
e) Showing your work, determine the probability that this couple will have a son with SMA. (2 marks)