Cladistic language concepts

[Michael Ghiselin]

----------------------------Original message----------------------------
 
          Dear Dr. Dyen,
               I must apologize to list members if something happened
          when I tried to forward your message.
               Also please forgive my delay in answering your
          commentary.
               Cladistics does run into problems where there is as you
          say some kind of amalgamation of lineages.  Sometimes the
          amalgamation is not so complete that lineages cannot be
          detected.  An interesting example has been the origin of
          mitochondria and chloroplasts from symbiotic bacteria.
               As to DNA, it turns out that the techniques that we use
          with it are pretty much the same sort of thing that we have
          used all along in comparative anatomy.  I spent a lot of
          time working with ribosomal RNA sequences and they worked
          pretty well.  But they did not show the clearness of
          resolution that we hoped for.  Some parts of the genome
          change very slowly, others more rapidly.  What we try to do
          for the very old relationships is find something that
          evolves very slowly.  Linguists try to find that sort of
          feature too.  The frustrating thing for us is that branching
          can occur repeatedly within a very short period of time, and
          the branches may not be evident in the slowly-evolving
          molecules.  We get a sort of bush instead of a tree.  I
          suspect that this has happened in linguistic evolution too.
           What the DNA does for us is give a lot of additional
          evidence and it often helps.  We will just have to keep
          plugging away.
          Sincerely,
          Michael Ghiselin