Why do we abbreviate trisomy as n + 1?

1 Answer
Oct 10, 2017

Here's the reason.

Explanation:

Firstly I would like to throw some light that n+1 is not an abbreviation of trisomy.

General abbreviation of trisomy is 2n+1.

n is the haploid number of chromosomes at a certain sequence.

Now, it's diploid is 2n.

Now, haploidy & diploidy are common intermediates of chromosomes.

But, an abnormal count of chromosomes is called aneuploidy.

Some aneuploid conditions are rarr

(1). 2n − 1rarr monosomy.
(because only one copy of same specific chromosome is present).

(2). n+1 rarr disomy.
(because two copies of same specific chromosome is present).

(3). 2n + 1rarrtrisomy.
(because three copies of same specific chromosome is present).

(4). 2n − 2 rarrnullisomy.
(because no copy of a specific chromosome is present).

Hope it Helps:).