A gene family has been accumulating nucleotide substitutions at a rate of 0.25 per million years.On average, there have been 80 substitutions between the common ancestor of this gene family and each of the various living forms of this gene.How many substitutions are expected to have evolved between any pair of living forms of genes from this gene family?

Question

Quizplus · Accepted Answer

To find the number of substitutions between any pair of living forms, we first calculate the time since their common ancestor. Given 80 substitutions at a rate of 0.25 per million years, it took 320 million years (80 / 0.25) for each lineage to evolve from the common ancestor. For two lineages, this time doubles, as each lineage evolves independently, leading to 160 substitutions (80 substitutions per lineage times 2).

A Gene Family Has Been Accumulating Nucleotide Substitutions at a Rate