ITN: The Utility of Evolutionary Theory
Elf M. Sternberg
http://news-service.stanford.edu/news/2005/november16/obe-111605.html
Hsueh explained that before he and his colleagues started the project,
they used the genome projects' information to create a database of GPCRs
that grouped them according to their evolutionary relatedness.
From the 300 GPCRs found in the human genome, the researchers selected
about 100 that had no known hormone partner. They then chose those 30
that seemed most likely to interact with a peptide hormone, basing this
choice on evolutionary analyses.
"These sequences stood out because they each have evolutionarily close
'sister genes' known to bind peptide hormones," Hsueh said.
Next, they focused on identifying the unknown hormone partners. Darwin
again lent a hand. Hsueh and colleagues narrowed the search by focusing
on sequences that have been conserved during hundreds of millions of
years of evolution-- in organisms as diverse as fish and humans--
because these are likely to be of greatest biological importance. They
zeroed in on several sequences, including the one known to make ghrelin,
the appetite-enhancing hormone. That sequence appears in humans and at
least 10 other mammals.
....
Instead of testing each of the 30 previously identified GPCRs, they
started with what the evolutionary record told them was the most likely
candidate. Their hunch was that the receptor for obestatin would be
closely related to the receptor for ghrelin. A whirl through their
database showed them that GPR39 was closely related to the receptor for
ghrelin.
Sure enough, later experiments showed them that GPR39 was in fact a
receptor for ghrelin's antithesis, obestatin.
So, will Nashton now shut up about evolutionary theory producing
nothing of use to scientists?
Elf
Skeets
>>They then chose those 30 that seemed most likely to interact with a peptide hormone, basing this choice on evolutionary analyses.<<
what does this mean?
>>"These sequences stood out because they each have evolutionarily close
'sister genes' known to bind peptide hormones," Hsueh said.<<
evolutionary is assumed. they could just have close sister genes
unrelated to evoution, right? iow, they saw the sister genes and
focused on these due to their similarity. the evolutionary aspect is
assumed and darwin is given credit.
isn't this backwards?
>>Next, they focused on identifying the unknown hormone partners. Darwin
again lent a hand. Hsueh and colleagues narrowed the search by focusing
on sequences that have been conserved during hundreds of millions of
years of evolution-- in organisms as diverse as fish and humans--
because these are likely to be of greatest biological importance. <<
i see the same problem here. they took the oldest sequences and used
the age as the basis of their decision. the idea evolution controlled
the age is assumed.
it would appear to me that the evolutionary hype cart is well ahead of
the reality horse.
Richard Dawkins
"Skeets" <skill...@yahoo.com> wrote in message
news:1132515959.5...@o13g2000cwo.googlegroups.com...
You beat me to it skeets.
jrs...@sbcglobal.net
Uh, it's called prediction...a valid theory has can make predicitions based
on assumptions.
>
Elf M. Sternberg
> >>"These sequences stood out because they each have evolutionarily close
> 'sister genes' known to bind peptide hormones," Hsueh said.<<
> evolutionary is assumed. they could just have close sister genes
> unrelated to evoution, right? iow, they saw the sister genes and
> focused on these due to their similarity. the evolutionary aspect is
> assumed and darwin is given credit.
> isn't this backwards?
Not at all. Evolutionary theory predicts that there are close
sister genes and that they would have similarity. They started from
those first principles and generated results. This is exactly what
science should do.
Your complaint is a bit like complaining that the inventor of
the nuclear bomb, who was working from first principles about the way
physics was known to work, then claiming that the bomb validated those
principles. They do, but only in a trivial way: the fact that the bomb
works was a given from the physics.
In this case, the evolutionary theory of descent with
modification and the preservation of core metabolic functionality was
assumed to be true, and by working with that assumption the researchers
produced results. They would have had to assume a much larger
collection of data had they not been able to discard huge swaths as
"unlikely" in a Darwinian scenario, and they may never have found what
they were looking for. Not only did evolutionary theory assist them in
their search, they got a hit on their first try.
Elf
NashtOn
Well done.
We will be seeing more of the ToE being hyped in the media because of
the ID "controversy?" Only time will tell, but the scientific herd seems
to me to be getting desperate to show how "useful" evolutionary theory
is at every turn, even though, as in this particular case, other
explanations could have sufficed to find what the researchers were
looking for.
Furthermore, if this is the best we can do with respect to the ToE and
its applied usefulness or utility, when obesity is due mostly to a
flagrant lack of education, especially since other postulates and models
could have also explained the results, it has a long way to go before
becoming truly useful for *real* disease, such as vaccines, cancer
treatment and cardiovascular disease.
Nicola
er...@swva.net
Maybe, but since evolution really happened, what conceivable good
purpose could be acheived by trying to hide it from the public?
Eric Root
Elf M. Sternberg
> We will be seeing more of the ToE being hyped in the media because of
> the ID "controversy?" Only time will tell, but the scientific herd seems
> to me to be getting desperate to show how "useful" evolutionary theory
> is at every turn, even though, as in this particular case, other
> explanations could have sufficed to find what the researchers were
> looking for.
Please, name an explanation for the parsimony of their results
that could have been acheived with any other set of assumptions than
those provided by basic evolutionary theory.
> Furthermore, if this is the best we can do with respect to the ToE...
If it works at all, you'll have to give up your resentment of
it.
Elf
Bob
>Well done.
>We will be seeing more of the ToE being hyped in the media because of
>the ID "controversy?" Only time will tell, but the scientific herd seems
>to me to be getting desperate to show how "useful" evolutionary theory
>is at every turn, even though, as in this particular case, other
>explanations could have sufficed to find what the researchers were
>looking for.
funny that ID is completely absent from the world's scientific
literature. if ID is a revolution...it's the quietist one in history.
>
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