Question

What is the numerical change in chromosome number, which is not the exact multiple of the haploid genome, known as?
(a) Triploid
(b) Allopolyploid
(c) Autopolyploid
(d) Aneuploid

Answer 1

Hint: The terms polyploid, haploid, diploid, etc. define a specific number of chromosomes that are multiples of the haploid genome. An example of this abnormality is Down’s Syndrome.

Complete answer:
Various abnormal changes in chromosome numbers cause damage to living cells and various disorders in the human body. The changes in the chromosome number are defined by various terms.
Aneuploid cells have an abnormal number of chromosomes that are not an exact multiple of the haploid genome. An example is a human containing 45 or 47 chromosomes in a diploid cell, which should have 46.
Examples of aneuploidy are Down’s syndrome and Edward’s syndrome.
- In triploidy, fetuses are born with three sets of chromosomes. One set of chromosomes contains 23 chromosomes and is known as a haploid set (n) . A diploid (2n) set of chromosomes has 46 chromosomes. A triploid (3n) set contains 23 + 23 + 23 = 69 chromosomes. Triploidy is a chromosomal abnormality.
- An allopolyploid offspring or strain has the genetic makeup for two different species, and the offspring is a hybrid and a different species than their parent species. The offspring has two or more sets of chromosomes from different species.
- Autopolyploid species have an extra set of chromosomes from their parent or an identical parent species. Most human cells are diploid in nature. If we derive another set of chromosomes, we are polyploid.
So, the correct answer is ‘Aneuploid’.

Note:
- Aneuploidy is known to be characteristic of cancerous tumors in the body.
- The difference between aneuploidy and polyploidy is that aneuploidy has an abnormal number of chromosomes that are not an exact multiple of haploid genomes while polyploidy has a chromosome number that is a multiple greater than twice the haploid number. Polyploidy does not always cause damage to the cell and is found in some human and plant cells.