mitteldorf's blog

Viruses invented DNA?

May 27, 2006

Patrick Forterre claims he can trace the origin of DNA by studying replication enzymes in modern viruses, some of which are similar to the chemistry used by higher life, and some of which are unique to viruses. Two other virtues of this theory:

* That viruses have an immediate fitness benefit from substituting DNA for RNA (a way to escape the host's defenses), while for cells, the switch to DNA offers only long-term benefits, so it evolves with more difficulty.

* That viruses evolve more nimbly than other organisms, because their reproductive cycle is so rapid and their survival ratio so low.

Old ideas about aging gain new respect

May 2, 2006

Since Darwin and August Weismann wrote about aging in the 19th century, it has always seemed apparent that animals are programmed to deteriorate with age, and ultimately to die. But to an evolutionary theorist, this idea is absurd. Natural selection chooses survival and reproduction - not death and destruction!

In recent years, genetic evidence has added to the impression that there is an evolutionary program for death. Now there is a theory about how natural selection might manage this feat.