Question

Aneuploidy is the term applied for the
A. Gene mutation
B. Chromosomal mutation
C. Chromosomal mutation involving the addition or loss of one or more chromosomes
D. Chromosomal mutation involving the addition of one or more complete set of chromosomes

Answer 1

Hint: Genetics is a branch of biology that helps in studying heredity. It involves study of genes, genetic variation, and principles of inheritance. Sir Gregor Mendel was referred to as the ‘Father of genetics’. There is inheritance of certain traits from the parents that are responsible for specific characters in the offsprings.

Complete answer:
Deoxyribonucleic Acid (DNA) is considered as a molecular basis for genes. Genetic information exists in the sequence of the nucleotides in the DNA chain. During cell division, their full genome is copied and each daughter cell gets one copy of that genome.

During DNA replication, some errors can occur in the polymerization of daughter strands. These errors are called mutations. Hence, the permanent alteration in the DNA sequence of a gene is called Gene mutations.

If mutation involves a large segment of DNA, which can be due to deletion, insertion, or inversion of a segment of DNA, this is called Chromosomal mutation. This leads to an abnormal number of chromosomes which is referred to as Aneuploidy. Aneuploidy involves chromosomal mutation which involves the addition or loss of one or more chromosomes from a single set.

So, the correct answer is Option (C), Chromosomal mutation involving the addition or loss of one or more chromosomes.

Note: Aneuploidy involves an abnormal number of chromosomes, which occurs when a single chromosome is missing from a pair, called Monosomy. Examples of Monosomy include Turner’s syndrome. If an individual has more than two chromosomes of a pair which may be Trisomy, Tetrasomy, and so on. An example of Trisomy includes Down’s syndrome due to the presence of an extra copy of chromosome number 21.