clar697
Forum Guru
Topics: 190
Posts: 199
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PARENTS:
MALE
a II b
a II d
FEMALE
b II b
c II f
OFFSPRING:
FEMALE: AFFECTED WITH DISEASE
b II b
d II c
MALE: AFFECTED WITH DISEASE
b II b
d II f
FEMALE: UNAFFECTED
a II b
a II f
Two children in a family have a disease characterized by mental retardation and mild dysmorphic features. The family was evaluated by standard karyotype and then by DNA microsatellite polymorphism studies for two autosomal markers. A pedigree is shown. Which of the following is the most likely cause of the congenital disorder?
A) Anticipation
B) Autosomal recessive inheritance
C) Genomic imprinting
D) Mitochondrial inheritance
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| hitesh
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Topics: 56
Posts: 713
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C) Genomic imprinting
Disease is occuring when "b" comes from both parents... But not when only maternal "b" is inherited. this could make this recessive, but interestingly, mother has 2 "b"s, and still does not have the disease..
So, it seems like the maternal "b"s got inactivated (imprinted) in the affected children, leading to disease state..
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Two down, 2 to go...
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