Red-green color blindness is caused by a mutation in a gene onthe X chromosome. X^a is the recessive mutant allele thatcauses color blindness; X^A is the dominant, functionalallele. You meet a patient who has Klinefelter syndrome (that is,he has an XXY karyotype). His mother is colorblind, but his father has normal colorvision. Your patient has both the X^Aand the X^a alleles.

1. You hypothesize that your patient’s syndrome is due to ameiotic nondisjunction event that occurred in: (circle the correctoptions) (2 pts)

thispatient                thispatient’sfather              thispatient’s mother

                                                MeiosisI         or        MeiosisII

1. In the space provided below, illustrate how the meioticnondisjunction event occurred, showing only the sexchromosomes. If you think it could happen in either meiosis I orII, pick one of these for illustration. (6pts)

1. Use the symbols below to illustrate the X and Ychromosomes:
2. Use arrow(s) to indicate the cell(s) that could give rise toyour patient’s abnormal karyotype.

1. You also find a small number of cells in this patient with onlyone X and one Y chromosome. Explain this phenomenon in no more thantwo sentences. Be specific about in whichindividual and roughly when this relevantevent might have taken place. (2 pts)