Question

What do you think constitutes a good genomic region for constructing a molecular clock and what are two reasons why nucleotide divergence might not be linear in time?

Answer 1

Mitochondrial DNA consideredas a good genomic region for constructing a molecular clock because recently, forensic scientists, anthropologists, and evolutionary biologists have looked at mutations within the DNA of the mitochondrion to explore differences between peoples and populations. Mitochondria are found in all eukaryotic cells and are believed to have once been free living bacteria that were assimilated early in evolution.

The process of evolution often erases evidence of previous evolutionary history by mutation and recombination which is not not remained constant over time. In DNA sequences, multiple substitutions at a site over the course of time erase earlier synapomorphies. They also cause the amount of sequence divergence between taxa to plateau, which is attained sooner in rapidly evolving sequences.