Inferring what the common ancestor of the great apes was

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In the past, before the dawn of modern genomics, many scientists have attempted to reconstruct the common ancestor of the great apes (to remind you, orangs, gorilla's, chimps and us) from morphological and behavioural traits of current apes, there are however a few problems with this approach i believe. First of all, the order of most recent to least recent common ancestry between the apes doest not necessarely reflect a morphological or behavioural progression that is as linear as one would think. Orangs, the least related to us, are more intelligent than chimps and gorillas by current estimates. Is this an example of convergent evolution, or did chimps and especially gorilla's diverge more cognitively from the common ancestor than us? i think only full genomic comparisons of all apes could give the answer (have not yet searched if any of these comparisons have been done or if we have full sequences for all). reconstructing the probably ancestral genome of a monophyletic group is relatively doable with modern statistical methods in genomics. So what do you think?

bikeguitarist, while your post is nice, please do not feel the need to defend evolution in this thread, this is called "preaching to the choir". discussing a specific aspect of evolution has nothing to do with discussions about evolution being true (which is an a priori assumption by anyone with a brain talking about these matters).

the idea that digging up fossils is still as important today is fallacious, the most interesting field of evolutionary study today is comparitive genetics, no doubt, because we are getting close to being able to computationally infer ancestral genomes from extant species of a monophyletic group (in case you don't know the term, all living descendants of a certain common ancestor). It's like how linguists reconstruct hypothetical ancestral languages of current languages, without any written sources of the ancestral language surviving. Same principles are used in this case, long live the power of statisticial analysis

since we are on this subject, i remember reading that currently it is actually assumed that two major families of bats, actually developed flight as CONVERGENT evolution, ie they do not share a common flying mammal ancestor, i do not know if this was based on genetic analysis, but if true, would be extremely interesting discovery.

Its a fascinating subject.
There was a book called "the Red Ape Heresy" written by an author who pushed the idea that we are descended from an Asian Orangutan-like ancestor and not the african chimp-like creature usually envisioned as our ancestor.
The book was largely a series of tables of traits that show that our "vital stats" are more lke those of the orangutans than those of the african apes.

The idea is (more than ever) still a scientific heresy.
Analysis of DNA shows that we are closer to chimps than to Orangutans, but there maybe a kernal of wisdom in this heresy.

The consensus is that humans are a type of African ape. The chimps, bonobos, and gorillas are our siblings, and the Orangutan is only our first cousin, the other asian apes (gibbons) are more distant cousins.

So - first there was a common ancestor of all great apes (asian and african), and then someime later there was a common ancestor of all African apes that sired us.

But though we have much in common with african apes- in a number of curious ways we are more like Orangs than we are like chimps and gorillas.
Male orangs have long flowing beards- for example- the only african ape wiith flowing male beards are some (but not all) races of humans.

We tend to assume that humans are the most evolved creature, but my guess is that we may have become human by being conservative in some ways- and by NOT evolving.

The similarities of humans and orangutans may be due to the fact that both the common ancestor of all apes, and the later common ancestor of all african apes was somewhat orangutan-like, and humans retain these older common traits which our chimp and gorillas reltives have abandoned. So its not that we are descended from oranguatans( instead of being an african ape)-its that we are more conservative than the other african apes and retain the same basal ape traits that orangutans also still have.

naturalplastic wow, that was an excellent answe to my question. it basically answers my questions why i think orangs seem more "human" than gorillas or chimps in some ways (in picture of orangs i always want to go be their friend, not so much with chimps and gorilla's) and the fact that orangs are closer to us in intelligence.. it always seemed to be that while genetic distance wise, we are further from organs, phenotypically we might share more with them than with the african apes. have orang genomes been analysed and compared to ours yet?

the part about not evolving.. i read recently that chimps seem to have diverged more genetically from the chimp-human ancestor than humans. and it is possible gorillas have also diverged more, and both of them have diverged more from the common ancestor of all great apes than orangs or us, in some ways (like cognitive ability, notice how orangs have a forehead and skullshape more akin to us, in fact chimps have nearly no discernible foreheead development.)

natural selection? genetic mutation is random and most mutations are lethal. well, maybe the orangutan is so very smart because somewhere down the line, smarter animals were more successful. it was the animal's defense against its environment. perhaps it was just divergence. after all, large animals like this take millions of years to evolve.

thanks for stating obvious things about the process of evolution.. now what does this have to do with our discussions of the common ancestor of the great apes?

@ devilinside, genetics is useful but not the be-all, end-all of evolutionary study. It can tell us, with a great deal of accuracy if multiple loci and/or SNPs are studied, how closely related two organisms are; however, it cannot tell us *why* they are different or what their common ancestor looked like. In the case of chimpanzees and humans, for example, our current estimation of a common ancestor is based on fossils, not genes.

In addition, even a full genome analysis is not necessarily going to answer all of our questions because a lot of what differentiates two species are not the genes themselves, but when and where and for how long the gene is activated as an organism develops. Epigenetic control of gene expression is arguably as important as the gene itself.

epigenetics is overrated.

sure, if you say so.

edit: a few examples
http://www.sciencemag.org/content/296/5566/340.abstract
http://www.genetics.org/cgi/content/abs ... v1?papetoc
http://giladlab.uchicago.edu/Research_2.html

glad you enjoyed my post.

That is interesting how chimps have evolved atleast as much or more than humans have from our common ancestor.

Although juvinile apes of all species are more human looking than the adult forms adult orangs, for some reason, do have a certain appeal that adult african apes (especially the males)generally dont have.
Clint Eastwood exploited that star power by directing several orangutan stared movies.

oh, if you're gonna call all non-protein coding changes epigenetics, that's something else entirely. "In biology, and specifically genetics, epigenetics is the study of inherited changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in the underlying DNA sequence". In other words, epigenetics refers to things like methylation of DNA sequences to prevent transcription, which can be inherited (seems to be limited to only a very few generations), or the modifications that are needed for cell lineage differentation (wouldn't want your neurons to be able to express liver cell genes i bet.)