Question

True or false:

Muscular distrophy in golden retrievers is a sex-influenced disorder because a homozygous recessive male will show the phenotype but a homozygous recessive female will not.

Answer 1

ANSWER: FALSE , it is rather an X linked disorder and not a sex influenced disorder.

EXPLANATION: Golden retrievers muscular dystrophy is an X linked recessive disorder in which male dogs are more commonly affected. Dystrophin gene is present on X chromosome. Since male has only one X chromosome, for a male to be affected, he has to receive only one X chromosome with defect from either of the parent. Whereas for a female dog to be affected, she has to receive defective X chromosome from both the parents which will be quite rare. Hence it is more common in a male dog than female.