PATHOLOGY

Detailed explanation-1: -Mutation is the ultimate source of all genetic variation, and is essential for evolution by natural selection: indeed, most of our genome has been shaped primarily by mutation and random drift.

Detailed explanation-2: -The ultimate source of genetic variability is the imperfect replication of DNA. DNA polymerase does not always incorporate the correct base when DNA is being replicated and this leads to the creation of new gene sequences upon which selection can act.

Detailed explanation-3: -Mutations are the original source of genetic variation. A mutation is a permanent alteration to a DNA sequence. De novo (new) mutations occur when there is an error during DNA replication that is not corrected by DNA repair enzymes.

Detailed explanation-4: -Darwin did not know that genes existed, but he could see that many traits are heritable-passed from parents to offspring. Mutations are changes in the structure of the molecules that make up genes, called DNA. The mutation of genes is an important source of genetic variation within a population.