Question

How do genetic changes accumulate?

Answer 1

Accumulation of genetic changes:

1. The alteration in the genetic makeup of an organism is due to the process of homologous recombination (cross-over between homologous chromosomes) during the meiotic division (reductional division) during sexual reproduction.
2. Therefore the changes in the DNA (mutation) of the parent are carried to the daughter cell.
3. They tend to get accumulated slowly in the gene pool over time.
4. This rate of change in DNA sequence can be measured using dated fossils on the key branches.
5. Hence, this data can be used as a molecular clock to locate the divergence of other lineages.
6. The figurative term used to calculate the mutation rate of biomolecules which will in turn help to deduce the time in the prehistory of the divergence of two species from one another is known as a molecular clock.
7. So, if there is a molecular clock, the number of changes from the common ancestor can be determined.
8. After that, by multiplying the two numbers it is possible to calculate the time it would take for that particular species to diverge from the particular ancestor.