Lesson 8 of 11 · 6 min
Mutation
NCERT § "Mutation"
One family member carries sickle-cell trait; it traces back, ultimately, to a single wrong letter in one gene, copied faithfully into every one of their red blood cells ever since.
The lesson in notes
In short
Mutation is a change in the DNA sequence, which changes the genotype and phenotype of an organism. Along with recombination, it is a source of variation.
Loss (deletion) or gain (insertion or duplication) of a DNA segment changes chromosomes. Such chromosomal aberrations are commonly seen in cancer cells.
Sickle-cell anaemia is the classic example of a point mutation, where only one base pair of DNA is changed.
Deletion or insertion of base pairs can cause frame-shift mutations.
Chemical and physical agents that cause mutation are mutagens; UV radiation is one of them.