Question

What are chromosomal mutations? How can they be induced?

Answer 1

Hint: Mutation is a phenomenon in which the sequence of nucleotides present in DNA is altered which results in the change of phenotype and genotype of an organism. As DNA is the part of chromosome any change in DNA leads to the change in chromosome.

Complete answer:
Any change in the chromosome which leads to rearrangement of chromosomes, or an abnormal number of an individual chromosome, or an abnormal number of sets of the chromosome is called chromosomal mutation.
Chromosomal aberration is commonly seen in cancer cells.
Euploidy- The mutation which leads to the change in the set of chromosomes is termed as Euploidy.
Aneuploidy- The mutation in chromosomes which leads to a change in the number of chromosomes is termed as aneuploidy.
Mutation can be induced by many chemical and physical factors. These external factors which induce mutation are called mutagens.
Ionic radiations, UV radiation and radiomimetic agents like bleomycin are some of the inducers which induce mutation.
There are three types of mutation-
Base substitution- This is a point mutation. In this mutation, at a certain point the base pair is substituted with another base pair. It is of two types –
TRANSITION- when purine is substituted with another purine.
TRANSVERSION- When purine is substituted with pyrimidine or when pyrimidine is replaced by purine.
Deletion- When one or more base pairs are removed from the DNA sequence.
Insertion- When one or more base pairs are inserted in the DNA it changes its reading frame and leads to mutation.

Note:
Chromosomal mutation leads to a number of diseases like Down's syndrome, klinefelter’s syndrome, Turner’s syndrome, Edward's syndrome, etc. These mutations can be passed on to different generations.