>On Fri, 14 Apr 1995, Brian Foley wrote:
>>> : I found in Science issue 31st March 1995 pagg.1907-1908 an interesting
>> : report about Goodman's theory of slower mutation rate in humans. This idea,
>>> << snip >>
> Patrick O'Neil wrote:
>>I would think that generation _time_ would be rather irrelevant (Unless
>your generation time is a million years :) ). I would think that the
>fact that mice have a less efficient DNA damage repair system than humans
>do, for instance, and so THIS would lead to a higher "clock rate" for
>them vs us, that is, sequence variations will occur at a higher rate per
>replication. Correcting for more rapid generation time, the mutation
>rate should itself be more important.
>>The clock rate for HIV, taking mutation rate into account, should then be
>extremely fast.
>
This would be correct IF all the changes in the DNA is due to damage (that
could be repaired). If mistakes happen during replication and replication
(that ends up in the germ line) occurs more often (via generations), then
generation time could also have effect. HIV mutation is fast due to the
lower fidelity of reverse transcriptase and the single stranded nature
of the virus ('error prone replication'). Reverse transcriptase cannot
'proofread' like DNA polymerase's 3'-5' proofreading activity. This is not
quite the same as damage repair because it would not be detected as 'damage'.
Just a thought and slight clarification.
Tim
email: tjk1846 at usl.edu
