an interesting graph

[chickenman]

the following comes from;
http://www.talkorigins.org/faqs/comdesc/camp.html

Figure C1. Distribution of genetic distances between human and mouse genes. The histogram is the actual data from 2,019 human and mouse genes. The solid curve shows the expected distribution of genetic distances assuming only a constant rate of background mutation (~10^-9 substitutions per site per year) (reproduced from Figure 3a in Kumar and Subramanian 2002).

hmmmmmm.........

 

[sulphur]

Is there similar evidence for orangatang and humans.With my limited genetic knowledge this seems to imply a massive pool of common genes are present and that mutations of those genesof those genes are putting the two species further apart. Please correct me.

 

[chickenman]

the implication is that the genetic differences between species follow a normal distribution, a common indicator of randomness in the variables. The solid line represents the expected graph if the divergence between the genes were simply the result of random mutations (genetic drift) - this is not a graph the IDists would like

 

[choccy]

Maybe I'm short sighted here, but what implications would this have for natural selecion? Shouldn't natural selection help preserve some mutations instead of others, and then shouldn't that be represented in the graph somehow? Or is this more a result of differing genes still being able to do approximately the same job? Like cytochrome c differs quite a bit between different organisms but are still cytochrome c and does pretty much the same job even though it's sequence is different.

Choccy

 

[ardipithecus]

Originally posted by sulphur
Is there similar evidence for orangatang and humans.With my limited genetic knowledge this seems to imply a massive pool of common genes are present and that mutations of those genesof those genes are putting the two species further apart. Please correct me.

 

I am fairly sure that there is no such evidence for orangs and humans because this kind of graph cannot be made until genome projects for two organisms being compared are well under way.  There is no orang genome project to my knowledge.  There will be a chimp genome project, but that is -- I believe -- only at the very begining of efforts.

 

 

[ardipithecus]

Originally posted by choccy
Maybe I'm short sighted here, but what implications would this have for natural selecion? Shouldn't natural selection help preserve some mutations instead of others, and then shouldn't that be represented in the graph somehow? Or is this more a result of differing genes still being able to do approximately the same job? Like cytochrome c differs quite a bit between different organisms but are still cytochrome c and does pretty much the same job even though it's sequence is different. 

Well most of the changes in genes are probably neutral since many mutations result in no change in the amino acid sequence or result in an amino acid subsitutions that have little effect on the phenotype.  Another thing is to consider that this is comparing many, many genes.  Some of them will undergo severe selection and some of them will not.  So a getting a bell or similiar type curve is not surprising even with natural section. 

 

 

 

[chickenman]

oh sorry guys, I should have clarified, the graph compares the redundant positions in the genes codons, thus it only measures neutral changes, natural selection isn't in effect.

You can read the paper here:
http://www.pnas.org/cgi/content/full/99/2/803