Question

Monosomic trisomy is

• A. 2n-1+1
• B. 2n-1-1
• C. 2n-1
• D. 2n+1+1

Answer 1

The correct option is A 2n-1+1

Changes in chromosome number by additions or deletions of less than a whole set is called as an aneuploidy. Monosomy is the absence of a single chromosome from a diploid cell (2n-1), the absence of two non-homologous chromosomes from a diploid cell is double monosomy (2n-1-1).

A diploid cell with an extra chromosome is trisomic (2n+1), a diploid cell with two different chromosomes in triplicate is called as double trisomy (2n+1+1).

The absence of single chromosome and presence of another chromosome in triplicate simultaneously is called as monosomic trisomy (2n-1+1).

Thus, the correct answer is option A.