STD 12 - 4. principal of inheritance and variation — BIOLOGY STD 12 Science — Question
Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYSTD 12 - 4. principal of inheritance and variation1 Mark
MCQ
Number of chromosomes in Down's syndrome are
A
$46$
✓
$47$
C
$48$
D
$49$
✓
Answer
Correct option: B.
$47$
b Down's syndrome is due to the trisomy of $21^{\text {st }}$ pair of autosome. Therefore, a Down's syndrome patient has $47$ chromosomes, i.e., $45 A + XX / XY$.
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