The Human Genome and Evolution

As a disclaimer I have no background in either genetics or biology, so I am not trying to make a point. I'm just looking for information. I'm a participant in the National Geographic "Genographic" project. Is it possible that through projects such as this or others that it will be possible to trace back human evolution to pre modern man or further.I guess what I'm really asking is, what is the connection, if any, between genetics and evolution, and will genetics ever be able to conclusively prove or disprove macroevolution.

Thread moved here from the Proposed New Topics forum.This is a very broad topic indeed. Most topics tend to be a bit more specific, but there is scope here for folks to attempt some concise and clear introductory level material on the relationship of genetics and evolution. So let's see what turns up...This message has been edited by AdminSylas, 06-27-2005 03:34 AM

As a first comment from a creationist (who is also a bioinformatics researcher) there is of course a big connection between evolution and genetics.We can see exactly how evolution works. In my previous institute we watched viruses *at the sequence level* mutate to become drug resistant.Evolution of course occurs through mutation (of various types), gene duplication, horizontal transfer (form one organism to another), recombination (mixing genes from parents) and, wait for it, natural (or artificial) selection.This does not mean it proves macroevolution.What we do see is that life is built on a common plan but with specializations built-in at all of the places you would expect - introduction of multicellularity, backbones, legs, respiration, immmune systems, placentas and so on.As we step from one genome to another we find numerous additions of gene types that bare no resemblance to sequnces whatsoever in the supposed anscestral genome despite the near identical 'house keeping' genes. Creationists, like myself prefer to point out these differences which we think demonstrate the handiwork of God. Evolutionists instead dwell on the core similarities between the genomes.This message has been edited by Tranquility Base, 06-27-2005 08:21 AM

It seems to me, just from a common sense point of view, that if evolution were just happening by natural selection that the genetic changes that occur in macroevolution would change incrementally one or two changes, of whatever type, at a time.If however there is divine intervention involved in the process it seems to me that it is more likely that several changes would occur simultaneously to bring about a new species.Does this make sense, and have biologists been able to sort out the rate of change that occurred in our evolutionary history, and if not, is there progress being made in this area?Thanks

Of course by this you mean by variation and then natural selection . . Agreed. The problem is we are only seeing a snapshot of genomic history. Numerous branches have become extinct - 'in-kind' for creationists, in-between forms for evolutionsist.So because we're only getting snapshots (via representations of extant branches) we're going to see large swags of genes added for either model. Evolution didn't have to be that way of course but evolutionists argue there are reasons why the in-between forms don't survive (which I only partly agree with).The key point is that even though we have a whole swag of genomes we can't use them to watch the step-by-step appearence of new genes. We even have several sets of very closely related genomes. Even there we don't see it. Evolutionists claim that the appearecne of new genes occurs quickly or in isolated groups and only comes to prominence in the population when it provides advantage.So suddenly we have new genes that bare no resemblance to old ones. It makes sense (even to me) but whether that process is responsible for the origin of the immune system or the eye is a matter of faith.On the other hand, DNA and protein sequences are systematically used to create evolutionary trees. The software simply produces the most 'parsimonious' tree that represents the sequences IF they evolved. It is precisely analogous to using a computer to produce a tree from anatomical measurements from fossils. The results agree to a large extent which is not surprising to creationists because everyone expects genotype (genes) and phenotype (appearance) to track significantly for obvious reasons.The key point tis that these seqence trees are derived using sequences that are shared. So it does not directly test macroevolution or address the origin of new genes.However, if macroevolution is a fact, then I would personally trust the outcome of sequence trees (becasue I trust them for in-kind variation). In that sense, your anthropological hopes are well founded. If we get more anthropological ancient DNA you should be able to use it to generate quite reliable trees (better than the poor anatomically based ones) tracking the origin of man. But it will rest on the *assumption* of macroevolution.This message has been edited by Tranquility Base, 06-27-2005 09:09 PM

Thanks a lot that helps a lot.Just so I understand what you mean by this; is it still considered macroevolution whether there is divine intervention or not. The term evolution seems to mean different things to different people.As far as I understand it the term evolution,(specifically macro evolution), still holds whether there is no divine intervention at all, if it is set in motion by divine intervention and then left to develop on its own, or whether it is divinely adjusted during the process. Would you agree?

It's possible you haven't fully followed a subtlety of my post. Although I'm a young-earth creationist I agree with the basic methods of biological evolution research. I just think that it mistkenly misidentifies 'progressive design' as an evolution process that never occurred (other than in the mind of God).So when I see a tree of life I see it as a relatedness chart in terms of biology and design not as in evoltuionary time. Firstly, the term macroevolution is not perfectly defined although I think it is still a useful term. Is the appearence of an extra set of legs due to a single mutation macroevolution? By most definitions it is and yet I'll agree it can happen! So in that sense I beleive in macroevolution. Do I believe the first leg arrived by macroevolution? No. Do I beleive most of the body plans, organs or senses arrived by macroevolution? No. Yes.The *usual* application of the term macroevolution would be without divine intervention. Many researchers would simply add divine intervention according to their personal preference (and still call it macroevolution).

Thanks. In the trials that are being conducted would it be conceivable then that human DNA could actually be traced back to a prehuman species? In simple terms what are the limits or do we know?

What you'll see is:* completely new genes
* lost genes
* point mutationsBut guess what: you get that with humans too. Amazingly there are entire stretches of DNA that we don't share.So it will be easy to place Erectus, Habilis, Neanderthal or Australopithicus into a tree but in the gray area it will be harder to determine if they fit into the human famiy or not.The poiint is that if you assume evolution a priori then we can already trace some of genes back to bacteria! But it doesn't prove macroevolutionary trees.This message has been edited by Tranquility Base, 06-28-2005 01:16 AM

If you gather genetic sequences from a number of individuals, you can infer the evolutionary history of those individuals back until you reach their most recent common ancestor. When genetic sequences are gathered only from members of the human species, the most recent common ancestor of the sampled individuals will by definition also be a human being. You can only trace human DNA back to a nonhuman species by including nonhuman species in the dataset - which of course has been done, but not by the genographic project.I believe the genographic project is more concerned with population processes within the species over historical time - for example the inference of migration patterns and demographic parameters.Hope this helps,MickThis message has been edited by mick, 06-28-2005 04:41 PM

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On the other hand, DNA and protein sequences are systematically used to create evolutionary trees. The software simply produces the most 'parsimonious' tree that represents the sequences IF they evolved. It is precisely analogous to using a computer to produce a tree from anatomical measurements from fossils. The results agree to a large extent which is not surprising to creationists because everyone expects genotype (genes) and phenotype (appearance) to track significantly for obvious reasons.

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But it's not just the genotype (as in all the genes of an organism's chromosomes) that is used, it is all sorts of DNA sequences, functional or otherwise. Why would we expect strong correlations between phenotypes and nonfunctional DNA sequences?

Hi Tranquility Base,You are thinking of phylogenetic trees that represent the genealogy of individuals (frequently members of different species). But it is also possible to build gene genealogies which reflect the phylogenetic relationships between alleles or even different genes rather than individuals.For example see the phylogenetic tree of opsin proteins on page 623 of this article. Note that the human genes are not clustered together, as we would expect from a species level phylogeny. Instead, the opsin genes responsive to different wavelength of light are clustered together. The nodes on such a tree correspond to the origin of new genes by duplication. Hence the phylogenetic method does actually address the origin of new genes.A bit off-topic but thought it would be of interest.Mick

Dear TB: Well I followed it alright. Apparently you are a dogmatic creationist who borrows all the terminology, methodology, and data of evolutionary biology and warps it to fit your predetermined, religiously motivated interpretation of reality. Shame on you. Your kind is the absolute worst, and the exact reason I started posting on sites like this one. I would say you are a pseudoscientific charleton hijacking the real data of real scientists and disingenuously re-interpreting it to selectively fit your world view without coming up with any valid data or testable theory of your own.Why aren't you and the rest of your ilk formulating your own hypotheses, generating your own evidence, and performing your own experiments to test and prove your world view? Why? Because your theories are NOT scientific in the slightest, you have no testable hypotheses, no experimental protocols, no basis for proving or disproving anything you say. Received any research funding lately? I thought not. No serious scientific entity would ever fund your endeavors to demonstrate the literal accuracy of biblical accounts. Perhaps then, you would be so generous as to describe just what process(es) gave rise to them WITHOUT resorting to terms 'borrowed' from evolutionary theory, which you apparently dismiss.You YEC types have yet to come up with a single objective definition of what a 'kind' is. It is NOWHERE adequately defined. Can you provide a defintion? It would be a 'YEC first'.I would not even be bothered by your facade of scientific 'understanding' if you were not trying to mislead people like GDR who are genuinely interested in advancing their understanding of evolutionary theory. Shame on you and all you hypocritical, religiously-motivated disseminators of falsehoods in the name of 'science'.Edited to correct an error and remove one or two overly irate adjectives.
This message has been edited by EZscience, 06-29-2005 05:50 AMThis message has been edited by EZscience, 06-29-2005 05:54 AM

Lurking admin warning...Careful, EZscience. I can appreciate a good rant; but just at the moment we moderators are getting a bit trigger happy. Calling a certain idea unmitigated drivel may be okay, if backed up. Calling a debating colleague a blithering idiot is probably not.I think also you need to revise one of your quote boxes to indicate TB as the author, not GDR.Thnx -- AdminSylas

Thanks mick
When you say it has been done can you outline the result in the simplest of terms?