Question

You are presented with a patient, named Gerry, who has Down syndrome (trisomy 21). You determine the nondisjunction event occurred in his mother, named Mary, during meiosis I. The TPTE gene is on chromosome 21. Mary has two different alleles of the TPTE gene (ex. T and t). Do Gerry's maternally-inherited chromosome 21s have the same or different alleles of the TPTE gene? Do not worry about recombination in this question. Same alleles Different alleles Not enough information to determine the answer

Answer 1

B. Difference alleles..Gerrys maternally inherited chromosome 21 may have different alleles of the TPTE gene which results in down syndrome and these alleles may be passed to Gerry from her parents.