Sickle cell anaemia is an example for the following type of mutations

Sickle cell anaemia is caused due to change in sixth amino acid Glutamic acid to Valine in β-polypeptide chain of haemoglobin or RBC. The codon for Glutamic acid is GAG.  In the template DNA strand the corresponding complementary sequence is CTC. CTC is changed to CAC i.e. a pyrimidine T is replaced by purine A and such type of replacement of a Purine with pyrimidine or vice versa is called Transversion substitution mutations. In transition mutation a purine is replaced by a purine or pyrimidine is replaced by pyrimidine. Frame shift mutation is due to deletion or addition of pairs of nucleotides in a DNA. Chromosomal mutations are due to change in number and structure of chromosomes.