In Down's syndrome of a male child, the sex complement is
Correct answer: B. XY
- A. XO
- B. XY
- C. XX
- D. XXY
Explanation
The correct option is b) XY. Down syndrome: also known as trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. It typically occurs due to nondisjunction during the formation of reproductive cells.
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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