Why are children of consanguineous (closely related) marriages at HIGHER risk of recessive genetic disorders?
ATheir genes mutate more frequently than usual
BConsanguinity blocks healthy gamete formation
CClose relatives lose their dominant alleles entirely
DClose relatives are more likely to share recessive alleles
Answer & Solution
Correct answer: D. Close relatives are more likely to share recessive alleles
1. Most recessive genetic disorders show only when a child inherits two copies of the bad allele.
2. Many people carry one bad allele without showing the disorder (heterozygous carriers).
3. Close relatives share more ancestry, so they are more likely to carry the same bad allele.
4. Two such carriers have a higher chance of producing a homozygous-recessive child.
5. That child would show the disorder.
6. So consanguinity raises recessive-disorder risk by sharing recessive alleles, not by changing mutation rate.
_Source: NCERT Class 10 Science Ch 9 'Heredity' (learncbse.in extract)_
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