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Re: Dino-fuzz found in amber?



On Fri, Sep 16, 2011 at 5:02 AM, Erik Boehm <erikboehm07@yahoo.com> wrote:
> Using statistics is still "guessing"

Not a random guess. After all, skeletal restoration of fossils - even
with a complete skeleton - is a guessing too, an educated guess, and
there is no problem with that.

> Your odds of guessing correctly may improve, but it is still not the original 
> DNA
> sequence.

Even with a sequence of *extant* organism we could not guarantee that
we have the original DNA sequence. There is an error associated.

> Also, I think the margin of error would be extremely high, what do you call 
> good? less
> than 1 out of 10 codons being incorrect?

As good as we could reconstruct an ancestral sequence of a gene from
comparative molecular biology - better, indeed, since we could have
many tests with the peptide sequence..

> You cant take an old amino acid sequence, and know the DNA sequence that 
> produced
> it. It doesn't matter what living sequences you compare it to.

Consider the leucine: UUA, UUG, CUU, CUC, CUA, CUG
Lets hypothetically consider that in the same place, in a sequence of
extant organism 1, we have isoleucine, coded by AUC. We could not be
100% sure, but it is, under parsimony assumption, likely that the
leucine code used is CUC.

[]s,

Roberto Takata