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Author Topic:   Alleles at the amino-acid/SNP level? Any experts out there?
Peter
Member (Idle past 1479 days)
Posts: 2161
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 3 of 14 (13984)
07-23-2002 3:35 AM
Reply to: Message 1 by Tranquility Base
07-22-2002 9:29 PM


quote:

4. What patterns are there? Two alleles seems to be very common but is this just in the simplified dominant/recessive case?

You also get co-dominance, where there are more than two alleles
(e.g. ABO blood groups, coat colour in cattle). In this
case the heterozygous phenotype is different from either
homozygous one.
I believe that even with eye-color the dom/rec model is simplified
because we also have grey, green, amber, hazel, etc. eye
colors.

This message is a reply to:
 Message 1 by Tranquility Base, posted 07-22-2002 9:29 PM Tranquility Base has replied

Replies to this message:
 Message 6 by Tranquility Base, posted 07-23-2002 7:28 AM Peter has replied

  
Peter
Member (Idle past 1479 days)
Posts: 2161
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 8 of 14 (14003)
07-23-2002 10:51 AM
Reply to: Message 6 by Tranquility Base
07-23-2002 7:28 AM


http://www.biotechinstitute.org/pdf/Vol_9_1_2pg.pdf
Has a snip of information on this. It would appear that
the O allele has a G missing.
http://www.artsci.wustl.edu/~jstader/Dickinson.htm
Also says that ::
"the gene encoding A, B, or O blood type can differ by four single nucleotide
polymorphisms. If the gene contains the sequence CGTGGTGACCCCTT, then it will produce antigen A. Antigen B is
produced by the same gene when four SNPs are inherited from a parent. In this case, the gene contains the sequence
CGTCGTCACCGCTA. When this gene encodes type O blood, it has the sequence CGTGGT-ACCCCTT. This
sequence differs from that of the A antigen by one base deletion, which is indicated by the dash. The result of this deletion
is a shift in the reading frame and a gene that produces no antigen at all (Czarnik, 1998)."

This message is a reply to:
 Message 6 by Tranquility Base, posted 07-23-2002 7:28 AM Tranquility Base has replied

Replies to this message:
 Message 9 by Tranquility Base, posted 07-23-2002 9:10 PM Peter has replied

  
Peter
Member (Idle past 1479 days)
Posts: 2161
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 10 of 14 (14118)
07-25-2002 4:30 AM
Reply to: Message 9 by Tranquility Base
07-23-2002 9:10 PM


Is there a way of knowing for sure that O comes
from a deletion, rather than A coming from an insertion
and B from a copy error of A ? (or A a copy error of B)
Or is this all guesswork at this level ?
As i understand it, it was formerly believed that O came first,
but now that A was first (there's a link lower to some
work on this).
OO has type O blood (like me) is that what you meant ?
http://www.er4yt.org/Education/Science_A2_Subtype.html
I think it tends to suggest that dominant/recessive model is likely
somewhat of a simplification though.
I also found this ineresting (although I don't agree with
the conclusions)::
http://www.lexiline.com/lexiline/lexi9.htm
Don't know much about the site itself, so checking up on the
data it presents ... but ...
It concerns primate blood groups and says that Chimps have A and O
blood types, but no B, while Gorillas have B and O but no A.
It also says that the earliest (supposed) human ancestral remains
are found in an area of africa where chimp and gorilla territories
overlap.
Other mammals (felines, canines, equines, etc.) do not have an
ABO blood type system (although cats have an AB system that is
somewhat similar, although the co-dominance is not apparent).
To me this says that there is some direct ancestral relationship
between man, chimps and gorillas. Common design seems less likely
since only the primates seem to have this blood group.
Perhaps man is the missing link between chimps and gorillas
This site:: http://www2.justnet.ne.jp/~shozo_owada/saitou-e.htm
Actually is suggesting that A was the original and both O and
B are mutations of this. It also suggests that there are many
more differences than those I cited previuosly.
More differences requires more time ??
I also, in the context of a previous question found this interesting::
"When we consider the direction of
substitutions, it is clear that there is a bias toward AT richness; G-to-A and C-to-T changes are much more abundant than A-to-G and T-to-C changes."
If some substitutions are more likely than others (for some
unknown but deterministic reason) doesn't that make parallel
evolution more likely. If we all start from the same place
and there are some 'rules' governing substitution then we
could all end up in a similar place.

This message is a reply to:
 Message 9 by Tranquility Base, posted 07-23-2002 9:10 PM Tranquility Base has replied

Replies to this message:
 Message 11 by Tranquility Base, posted 07-28-2002 11:15 PM Peter has replied

  
Peter
Member (Idle past 1479 days)
Posts: 2161
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 12 of 14 (14367)
07-29-2002 3:41 AM
Reply to: Message 11 by Tranquility Base
07-28-2002 11:15 PM


quote:
Originally posted by Tranquility Base:
Peter
Since (from the source you or someone posted) we discovered that O 'produces no antigen' then that would be the reason to suspect that O is due to a deletion. A single insertion wont make an active gene from random DNA. DNA coding for a functional and folded protein far more easily will yieled non-functional alleles by deletions. I'm not trying to argue as a creaitonist here - this is standard Mol/Struc Biol.

That makes sense ... I wasn't asking as an evolutionist ... just
asking in general. Some of the other references suggest that O
came from A too.
quote:
Originally posted by Tranquility Base:

The key point is that A and B are probably active functioning enzymes or something. Life is not ust a series of letters - the genes code for functioning enzymes and structural proteins. I'm not trying to kid anyone here.
I would love to know the details of waht protien A and B code for.

I think that's more or less covered in some of the links I posted.
quote:
Originally posted by Tranquility Base:

So OO is type O blood (like me) so it can't be overly important (if our fact that O is inactive is true)!

Not unless you need a tranfusion (People with type O blood
can only have type O blood, but anyone can have ours, provided
the rhesus factors are OK (I'm negative so I'm a universal donor))
quote:
Originally posted by Tranquility Base:

I agre dominant/recessive model is a simplification but in some cases it will be a warranted one.
In principle deterministic mutaitonl baises would make parallel evolution more likely - I agree. But it is truly imposible to imagine a scenario where this could take us from random DNA to DNA that codes for folded proteins that have just the right functions! I can imagine a functional gene in chimps and man mutating to the same thing due to either (i) a codon bias or (ii) something that is tolerated (or even advantagesou) in both species.

Only sequences that produce working proteins (whatever they
work for) would 'survive' though in a ToE sense. Once there
us a simplistic organism (maybe one of those RNA jobbies) producing
working proteins, they would multiply, and the evo process gets
a foothold.
In our timescale we have about a billion years to develop the first
working protein set after all. (Is that an american billion or
a british billion?)

This message is a reply to:
 Message 11 by Tranquility Base, posted 07-28-2002 11:15 PM Tranquility Base has replied

Replies to this message:
 Message 13 by Tranquility Base, posted 07-29-2002 4:03 AM Peter has replied

  
Peter
Member (Idle past 1479 days)
Posts: 2161
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 14 of 14 (14373)
07-29-2002 5:07 AM
Reply to: Message 13 by Tranquility Base
07-29-2002 4:03 AM


quote:
Originally posted by Tranquility Base:
^ American billion (10^9). The Brit one got redefined to the American one (and they abolished milliard) I'm pretty sure. I've never heard of Brit's talking about milliard-year old universes (thankfully)!

Thanks ... I've wondered that for ages

This message is a reply to:
 Message 13 by Tranquility Base, posted 07-29-2002 4:03 AM Tranquility Base has not replied

  
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