Birth-and-Death Evolution in Mammalian Gene Families

Once we recognize the accidental nature of evolution as described in birth-and-death evolution of gene families [The Evolution of Gene Families] we are better prepared to appreciate the significance of other studies.

In an earlier posting [Mammalian Gene Families: Humans and Chimps Differ by 6%] I described the results of Demuth et al. (2006) who looked at global expansion and contraction of gene families. They published this diagram to show the extent of gene loss and gain in mammalian lineages.

Figure 1. Distribution of gene gain and loss among mammalian lineages.

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The Creationists made a big deal about this when the paper first came out but we can now see that the expansion and contraction of gene families is just part of the normal, ongoing, process of birth-and-death evolution.