Shorter generation times speed molecular evolution

It’s not an especially surprising result, but it’s good to confirm what seems intuitively to be true.  Here’s the abstract from the Science research paper:

Rates of Molecular Evolution Are Linked to Life History in Flowering Plants

Stephen A. Smith* and Michael J. Donoghue

Variable rates of molecular evolution have been documented across the tree of life, but the cause of this observed variation within and among clades remains uncertain. In plants, it has been suggested that life history traits are correlated with the rate of molecular evolution, but previous studies have yielded conflicting results. Exceptionally large phylogenies of five major angiosperm clades demonstrate that rates of molecular evolution are consistently low in trees and shrubs, with relatively long generation times, as compared with related herbaceous plants, which generally have shorter generation times. Herbs show much higher rates of molecular change but also much higher variance in rates. Correlates of life history attributes have long been of interest to biologists, and our results demonstrate how changes in the rate of molecular evolution that are linked to life history traits can affect measurements of the tempo of evolution as well as our ability to identify and conserve biodiversity.  Science

Here’s some more of the history, specifics, and commentary on the results.

Perhaps I should add that Behe operates on this assumption, particularly in his Edge of Evolution.  This does not, of course, change anything about how unfounded his assumptions are (like assuming that only two changes to one gene were needed, just because these are the only two changes in common within the sets of many changes found in one type of resistance to chloroquine), and the vast lacunae in his calculations which bypass fitness issues which are crucial to fixation by natural selection (that is, he totally ignores in his calculations the fact that chloroquine resistant P. falciparum are less fit in the absence of chloroquine). 

Which just goes to show that you can’t get everything wrong, no matter how pathetic your knowledge base and capacity for scientific judgment is.

Explore posts in the same categories: Darwin's Black Box

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