Question

A plant species has 2n = 18 chromosomes. How many chromosomes would you expect to find in a tetrasomic individual of this species?

a) 16
b) 18
c) 20
d) 22

Answer 1

A tetrasomic individual of a plant species with 2n = 18 chromosomes would have 20 chromosomes, which is 2n + 2 due to the extra pair of one specific chromosome.

Step-by-step explanation:

If a plant species has 2n = 18 chromosomes, a tetrasomic individual of this species would have 2n + 2 chromosomes.

Tetrasomy is a type of aneuploidy where there are four instances of a particular chromosome instead of the usual two. Since the normal diploid number is 18, adding two more chromosomes due to tetrasomy results in a total of 20 chromosomes in a tetrasomic individual. Therefore, the correct answer is (c) 20.