Morris Goodman’s hominoid rate slowdown: The importance of being neutral

Half a century ago, when the field of molecular evolution did not even exist, Morris Goodman analyzed profiles of immunological interactions between species and reached the following two remarkable conclusions: first, protein evolution slowed down in the human lineage compared to other primate lineages; second, this slowdown was more pronounced for proteins whose functions were likely to be neutral. It took several decades of research to fully grasp these ideas and document the pattern of hominoid rate slowdown. Along the way, studies of hominoid rate slowdown led to major progresses in understanding determinants of neutral molecular evolution, which in turn is used to calibrate rates of adaptive evolution. Furthermore, the growing knowledge on the origin of mutations provides a basis for understanding differential evolutionary rates between sex chromosomes and autosomes, which has deep implications for inferring human evolutionary histories, and other aspects of molecular evolution. Primate genomics in particular stand to provide critical information in these pursuits, due to the abundance of genomic data, relatively rich documentation of life history traits, and several model systems, including our own species.

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► Morris Goodman first proposed ‘hominoid rate slowdown’ based upon the strengths of immunological cross-reactions.
► More pronounced for neutral mutations.
► Genomic data strongly support the hominoid rate slowdown.
► Can be explained by the generation time effect.