The real significance of ancient DNA

And why do the shells… remain quite unaltered … after such migration to milder seas. Be so good as to explain all this in your next letter. —Charles Lyell, letter to Charles Darwin 17 June 1856 (Burkhardt and Smith, 1990, p. 146). The arctic forms, during their long southern migration and re-migration northward, will have been exposed to nearly the same climate, and … they will have kept in a body together… (Darwin, 1859, p. 368). One of the...