NEET BIOLOGY

Detailed explanation-1: -A gene variant is a permanent change in the DNA sequence that makes up a gene. This type of genetic change used to be known as a gene mutation, but because changes in DNA do not always cause disease, it is thought that gene variant is a more accurate term.

Detailed explanation-2: -A mutation is a change in a genetic sequence. Mutations include changes as small as the substitution of a single DNA building block, or nucleotide base, with another nucleotide base. Meanwhile, larger mutations can affect many genes on a chromosome.

Detailed explanation-3: -Definition English: Any event that changes genetic structure; any alteration in the inherited nucleic acid sequence of the genotype of an organism.

Detailed explanation-4: -Chromosomal aberrations are changes in chromosome structure or number. Most chromosomal aberrations are known as aneuploidies, or different numbers of chromosomes other than pairs.