The raw material of evolution

Estimates of whale mutation rates contribute to understanding evolutionary processes Evolution happens when the code of life, DNA, is changed by the process of mutation. Mutations include deletions and insertions, rearrangements, and transpositions (moving DNA). However, it is the rate of point mutations, which affect a single site in the chain of nucleotides that make up DNA, that is most often considered. Knowing the rate and pattern of mutation is essential to understanding the process of evolution. This knowledge increases understanding of natural selection and has applications such as tracking demography and dating phylogenies, but calculating the mutation rate is not straightforward. On page 990 of this issue, Suárez-Menéndez et al. ( 1 ) use parent-offspring trios and genome sequences to estimate rates of point-mutational change from one generation to the next in four species of baleen whales in the North Atlantic: humpback ( Megaptera novaeangliae ), blue ( Balaenoptera musculus ), fin ( Balaenoptera physalus ), and bowhead ( Balaena mysticetus ).