Mr rahul is suffering from hypertrichosis and phenylketonuria. The probability of a sperm having one recessive autosomal allele and holandric gene is?

1/8
1/16
1/2
1/4

Hypertrichosis is a condition in which there is an excessive hair growth all over the body of the affected individual. It is also known as werewolf syndrome. It is an X linked genetic disorder showing dominant pattern of inheritance. Phenylketonuria is a genetic disorder caused due to presence of recessive allele that results in decreased metabolism of the amino acid phenylalanine. Holandric genes are the genes present on the Y chromosome. Now in this question, the patient is suffering from phenylketonuria and hypertrichosis. This means, all the sperms will carry the recessive autosomal allele responsible for phenylketonuria. Whereas, since hypertrichosis is X linked dominant disorder, half the sperms will be X (and would carry the disease causing gene), while rest half would be Y. In other words, half the sperms will get the holandric genes (present on Y chromosome). Thus the probability of a sperm having one recessive autosomal allele and holandric gene is - the probability of sperm having recessive allele (=1) multiplied with probability of a sperm having holandric gene (=1/2). = 1*1/2 = 1/2