[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Rconstructing DNA (was Re: Dino-fuzz found in amber?)
Roberto Takata <email@example.com> wrote:
> Of 60 codons, 14 would be dubious for the first and second position
> analysing only the aa sequence and using the vertebrate mithocondrion
> genetic code table. Using G. gallus DNA sequence as a guide, those
> positions for 8 codons was right, 3 was wrong and 3 could not be
> determined. Surely it is an improvement.
I think Dora Smith had a point when she said: "Well, I think that the
assumption that the least possible change occurred over time most
parsimoniously implies that evolution itself does not occur."
Simply filling in the blanks in a _T. rex_ DNA sequence based on the
chicken DNA sequence goes way further than parsimony.
> It is not ignored. What is regarded is that, under parsimony, as few
> mutations as possible is allowed (or we could use other parameters as
> codon usage bias, transition/transversion rate and so on to build a
> more complex model).
Yes, the model could be very complex indeed. And yet, this model
would still be utterly useless.
> The technique could be tested with extant organisms - and I did it
> with birds and croc. And yes it could potencially be tested for T-rex.
> Lets put aside the possibility of ancient DNA be obtained. We could
> get eventually more proteins.
More _T. rex_ proteins (even assuming we have any now) would still be
no help at all in reconstructing the exact DNA sequence.
> It must be taken into account, but it is not the only factor. As I've
> said: the secondary and tertiary strucuture of mRNA is very important.
> Even some post-translational modification depends on the some
In these cases, I thought that the untranslated regions (UTRs) of the
mRNA were paramount. Much more so than the part that is translated