2. Uniparental disomy is a rare phenomenon in whichonly one of the parents of a child with a recessivedisorder is a carrier for that trait; the other parent ishomozygous normal. By analyzing DNA polymorphisms, it is clear that the child received both mutantalleles from the carrier parent but did not receive anycopy of the gene from the other parent.a. Diagram at least two ways in which uniparentaldisomy could arise. (Hint: These mechanismsall require more than one error in cell division,explaining why uniparental disomy is so rare.)Is there any way to distinguish between thesemechanisms to explain any particular case ofuniparental disomy?b. How might the phenomenon of uniparental disomyexplain rare cases in which girls are affected withrare X-linked recessive disorders but have unaffectedfathers, or other cases in which an X-linked recessive disorder is transmitted from father to son?c. If you were a human geneticist and believed oneof your patients had a disease syndrome caused byuniparental disomy, how could you establish thatthe cause was not instead mitotic recombinationearly in the patient’s development from a zygote?
2. Uniparental disomy is a rare phenomenon in which
only one of the parents of a child with a recessive
disorder is a carrier for that trait; the other parent is
homozygous normal. By analyzing DNA polymorphisms, it is clear that the child received both mutant
alleles from the carrier parent but did not receive any
copy of the gene from the other parent.
a. Diagram at least two ways in which uniparental
disomy could arise. (Hint: These mechanisms
all require more than one error in cell division,
explaining why uniparental disomy is so rare.)
Is there any way to distinguish between these
mechanisms to explain any particular case of
uniparental disomy?b. How might the phenomenon of uniparental disomy
explain rare cases in which girls are affected with
rare X-linked recessive disorders but have unaffected
fathers, or other cases in which an X-linked recessive disorder is transmitted from father to son?
c. If you were a human geneticist and believed one
of your patients had a disease syndrome caused by
uniparental disomy, how could you establish that
the cause was not instead mitotic recombination
early in the patient’s development from a zygote?
Trending now
This is a popular solution!
Step by step
Solved in 2 steps with 1 images
