You are presented with a patient, named Gerry, who has Down syndrome (trisomy 21). You determine that the nondisjunction event occurred in his mother, named Mary, during meiosis I. You are interested in the TPTE gene, which is near the centromere of chromosome 21. Virtually no recombination occurs between the centromere and the TPTE gene. Mary has two different alleles of the TPTE gene. Would Gerry\'s two chromosome 21s from his mother have the same or different alleles of the TPTE gene? Or do you not have enough information to decide? Explain your answer by drawing meiosis I and II for Mary\'s chromosome 21. Use \"A\" for one allele and \"a\" for the other allele of the TPTE gene. Only draw the chromosomes relevant to this question (Do not draw all 46 chromosomes). Solution a. Nondisjunction produces abnormal gametes. Nondisjunction in meiosis I occurs during anaphase I when one pair of homologous chromosomes fails to separate.Trisomy is the condition of having 3 copies of one chromosome type. It is designated as 2n + 1 because the cell has the normal two sets of each 23 types of chromosomes plus an extra copy of one chromosome. I think Gerrys two chromosome 21s from his mother have different alleles (A and a) of the TPTE gene. But more information could be needed to explain and understand this in a much better way..