GATE 2022 BT – Question 27
Assuming independent assortment and no recombination, the number of different combinations of maternal and paternal chromosomes in gametes of an organism with a diploid number of 12 is _________________.
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Correct answer: 64
Explanation
In a diploid organism with $2n=12$ there are $n=6$ pairs of homologous chromosomes. Each pair carries one maternal and one paternal chromosome.
**Independent assortment.** At meiosis I each pair lines up independently, and a gamete receives one chromosome from each pair, either the maternal or the paternal copy. With no recombination, each pair gives 2 choices:
$$2\times2\times2\times2\times2\times2=2^6=\mathbf{64}.$$
(In general the number of combinations is $2^n$.)