Re: Limits of Kinds - now its crabs

Glenn Morton (
Tue, 18 Nov 1997 18:10:36 -0600

At 11:14 PM 11/17/97 -0800, Arthur V. Chadwick wrote:

>I would ask how can the rates of amino acied change in proteins (or
>ucleotide bases in DNA) be used as biological clocks? If these are
>indications of the passage of time then stasis is an argument against time.

I would probably have to agree that the molecular clocks are suspect. There
is also evidence that even the mitochondria are under natural selection
which alters the rate of the clock.

>These are still minor changes, possible controlled by change to a single
>homeotic gene. They are equivalent to the differences among the 600 or so
>species of Drosophila endemic to the Hawaiian Islands.

OK, then how much change can one get if he changes 2 or 3 or 4... of the
homeotic genes? What is the limit to change? and why must we only allow one
of the homeotic genes to change? I don't think you will hold to a position
that only one can change, but there have been some recently who have said
that there is a limit to change and I see none.

If I have a set of 12 numbers:


and I start mutating them one location at a time. What is the limit to
change? only the number of positions. In a dna genome there are the
equivalent of 3.5 billion numbers which can be changed by mutation. I see no
reason why there must be a limit to change in that sequence other than the
death of the organism or its failure to reproduce.


Foundation, Fall and Flood