Re: new method of evolutionary change

Robin Mandell (rmandell@jpusa.chi.il.us)
Thu, 17 Dec 1998 20:08:29 -0600

At 02:26 PM 12/17/98 -0400, you wrote:
>[snipped various old parts]
>>> However, there are
>>>a few points in animal evolution where the amount of DNA has about doubled
>>>and the number of copies of certain genes has increased.
>>Could you name one of those points and how we are aware of a "point in
>>animal evolution"
>
>One point is around the transition from invertebrates to vertebrates. I do
>not remember what organisms have been checked. At least many invertebrates
>and vertebrates have been checked, and the vertebrates have consistently
>much more DNA and more hox genes. I think lancelets (also known as
>amphioxus, Branchiostoma I believe is the main modern genus) have similar
>amounts of DNA to other invertebrates. They are the closest living
>relatives of vertebrates. Assuming that the animals (or at least the
>chordates) are all descended from a common ancestor, at some point the
>extra DNA must have appeared. All vertebrates have it and it seems no
>invertebrates have it, it must have occured in a common ancestor of all
>modern vertebrates. By supplying extra DNA to work with, the mutation
>could have been the impetus for the evolution and diversification of
>vertebrates. I think American Scientist had a good article on this
>recently, but could be mistaken about the journal.
I see, I thought by point in animal evolution you meant a point time but
you mean a point of division in modern organisms, correct? I thought maybe
there
was some evidence from a genetic event in the past that was documented somehow
from what you said. For someone uncomfortable with evolution wouldn't they
just
say that the vertebrates are more complex thus designed from the start with
mor DNA.

I am straight on the color filled monkeys, thanks.
The freedom/control thing I am gonna think on for a bit.