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Author Topic:   Look Long upon a Monkey's Genes
lpetrich
Inactive Member


Message 1 of 5 (72252)
12-11-2003 6:13 AM


Ennius (2nd cy. BCE):
Simia quam similis turpissima bestia nobis.
The monkey, that very ugly beast, how like us!
William Congreve, Letters upon Several Occasions (1695):
I confess freely to you, I could never look long upon a monkey, without very mortifying reflections.
A rough draft of the chimp genome sequence is now out, though the first analyses will be published next year:
http://www.genome.gov/11509418
http://www.genomenewsnetwork.com/articles/12_03/chimp.shtml

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 Message 2 by Loudmouth, posted 12-11-2003 3:22 PM lpetrich has not replied

  
Loudmouth
Inactive Member


Message 2 of 5 (72320)
12-11-2003 3:22 PM
Reply to: Message 1 by lpetrich
12-11-2003 6:13 AM


Thanks for the info, very interesting indeed. Just as a sidenote, our ability to sequence DNA seems to following Moore's Law. Like computer chips, every 18 months we are able to read sequence twice as fast at the same cost. Right now that means more machines, but techniques are getting quicker as well. Just from memory, there was a sequencing lab in a journal about two years ago that claimed they could do an entire bacterial genome (around 5 megabases) in a day and a half after they completed their shotgun library. Exciting times indeed.

This message is a reply to:
 Message 1 by lpetrich, posted 12-11-2003 6:13 AM lpetrich has not replied

  
PE's been savaged
Inactive Member


Message 3 of 5 (72556)
12-12-2003 2:59 PM


Couple of questions
Given that the chimp genome has now been sequenced. I wonder if anyone who knows more about this sort of thing than me would be able to tell me:
1. whether the analysis means we'll be able to estimate a minimum number of mutation events since the common ancestor which separate homo sapiens sapiens from chimps? (based on a comparison and statistical analysis between the two sequences).
2. whether this means that we'll be able to work out the exact dna sequence of our common ancestor? Or even very approximately?
2a And does this mean that, if some date in the future we work out what the genes actually do, we'll be able to reconstruct what this common ancestor was like?
One thing which has always puzzled me is whether we can work out what the universal common ancestor (believe its referred to as LUCA) could be if we sequenced enough genomes of different species, on purely statistical grounds.
Or if someone could point me to some reference material (for an ignorant but interested non-biologist), that would be great.
PE (BS)
------------------
This is Primordial Egg having to operate under a different name due to an unfortunate posting injury. This id will buthcered once I get my old one back

  
lpetrich
Inactive Member


Message 4 of 5 (72635)
12-13-2003 12:54 AM


Loudmouth: such fast sequencing could make molecular phylogeny much more useful, because having lots of gene sequence on hand tends to improve the resolution and reliability of molecular-phylogeny methods. This could help resolve a lot of riddles of evolution where molecular methods still do not give clear results, like early protist evolution.
PE 1: It may indeed be possible to estimate the number of change-of-function mutations from comparisons of genes. Those with changed functions will likely have more differences than one would predict from genes known to have unchanged functions.
PE 2: That may certainly be possible -- in fact, that's been done for some proteins, like a vision pigment of the shared ancestor of birds and crocodilians.
PE 3: One would have to know how to translate genes into shapes for that, but in principle, it ought to be possible.
As to the universal common ancestor, there has indeed been some work on that. Here are two references:
Brooks DJ, Fresco JR, Lesk AM, Singh M.
Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code.
Mol Biol Evol 2002 Oct;19(10):1645-55
Here in PubMed
(Finds that the common ancestor's proteins were enriched in the amino acids that are easier to make prebiotically)
Davis BK.
Molecular evolution before the origin of species.
Prog Biophys Mol Biol 2002 May-Jul;79(1-3):77-133
Here in PubMed
(tracks some proteins back before the common ancestor)
Ferredoxin, an iron-sulfur protein involved in electron transfer (an important metabolic process) is the oldest one; it has a negatively-charged "tail" that can attach to a mineral surface. This means that ferredoxin can be older than well-defined cells, suggesting a Haeckelian Urschleim phase.
Finally,
LUA -- last universal ancestor
LCA -- last common ancestor
LUCA -- last universal common ancestor

Replies to this message:
 Message 5 by Primordial Egg, posted 12-13-2003 7:04 PM lpetrich has not replied

  
Primordial Egg
Inactive Member


Message 5 of 5 (72759)
12-13-2003 7:04 PM
Reply to: Message 4 by lpetrich
12-13-2003 12:54 AM


Thanks.
PE

This message is a reply to:
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