Question

Rates of molecular evolution are highly ______ among loci and lineages

a. variable

b. uniform

c. predictable

d. statistical

Answer 1

The molecular evolutionary rate measures the frequency with which DNA or protein sequence mutations are fixed (i.e., shared by most individuals) in a population. Rate is highly variable among loci and lineage. Because, the mutations often derive from DNA replication errors or mutagens in the environment. Organismal-level traits and population genetic processes, in turn, could influence the frequency of DNA replication errors and mutagen levels. Mutations are transmitted from generation to generation in the germ cell line of sexually reproducing organisms. Because DNA in germ cells replicates during meiosis (gamete differentiation), we expect short-lived species to have higher mutation rates. As mutation are random so do evolution rates.