NEET BIOLOGY

Detailed explanation-1: -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-2: -Genetic mutations include substitutions, insertions, or deletions, while chromosomal mutations include duplications, deletions, or inversions. Spontaneous mutations occur as mistakes in copying DNA, while induced mutations are caused by external factors like radiation or chemicals.

Detailed explanation-3: -A chromosome mutation that causes individuals to have an abnormal number of chromosomes is termed aneuploidy. Aneuploid cells occur as a result of chromosome breakage or nondisjunction errors that happen during meiosis or mitosis.

Detailed explanation-4: -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.