Paul Neubauer Oct2893 01:48PM The Aquatic Ape news FollowupTo: talk.origins In article 204

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Paul Neubauer Oct-28-93 01:48PM The Aquatic Ape - news Organization: Ball State U. From: 00prneubauer@leo.bsuvc.bsu.edu (Paul Neubauer) Message-ID: <1993Oct28.164813.24116@bsu-ucs> Followup-To: talk.origins Newsgroups: talk.origins,sci.bio,sci.skeptic In article <2043@rand.mel.cocam.oz.au>, pjd@cocamrd.mel.cocam.oz.au (Pat Dooley) writes: > The geological history of NE Africa provides a locale for the > evolution of the AAT. There are no fossils from the period during > which the aquatic phase occurred, but the fossils of the descendents > of the AA have been found close to lakes and in a distribution that > suggests radiation from the NE African locale down the Rift valley. > The Baboon marker gene, or rather its absence in Homo sapiens and > non-African primates, supports the idea of a period of evolution > occurring outside of mainland Africa. I followed up on an earlier reference to the baboon marker gene, but (possibly because my site does not regard either alt.books.review or sci.anthropology (!?) to be valid groups) I posted (I presume successfully) only to talk.origins. Apparently Pat Dooley is following this discussion from some other group and no one else seems to have seen fit to respond. (I don't even know if the posting got out.) Anyway, I will have at it again and will mail a copy of this posting to Pat Dooley. Our university library does not have _Scars of Evolution_ so I am not able to consult it readily. However, the baboon marker gene argument strikes me as quite incomprehensible. A number of people who I have some reason to believe to be both smart and sane seem to be supporting or at least for the sake of debate taking a position of support for the AAT. Perhaps someone will see fit to correct me if I am misunderstanding the point of the baboon marker gene argument. It is generally believed that genes are passed from parent to child, and more generally from ancestor to descendant. If this belief turns out to be incorrect, then we have much bigger problems than the debate concerning the AAT vs. the savannah theory. (;-) On the other hand, if we retain the standard assumption about genes, then either the baboon marker gene argument is irrelevant or other major assumptions about the relatedness of humans to other primate species will have to be overturned in a radical way. Consider the following (sketchy, but otherwise relatively standard) cladogram: primates / \ ... old-world monkeys / \ monkeys apes / | \ / \ ... baboons ... orangutan * / \ Gorilla * / \ Pan Homo / \ chimp bonobo This cladogram certainly supresses a number of nodes, but strikes me as being reasonably standard insofar as it represents the relationship of the members shown. Under the assumption that this cladogram has any relation to reality, a gene shared by "all African primates" would have to have been introduced at least as early as the node labeled "old-world monkeys" and then the gene would have to have been lost (independently) in Pongo (the orang) and Homo, but retained in the lineages (other than Homo) that inhabit Africa. If the above cladogram is correct, then (pace other weird and ad hoc assumptions about genetics) it must be regarded as simply a coincidence that neither orangs nor humans possess the baboon marker gene while baboons and chimps do. A gene is not like a the family photo album. There is no known mechanism that would cause a gene to be lost simply by virtue of its posessor moving, the way moving to a new house can cause one to lose one's more alienable belongings :-(. If there is any force to the baboon marker gene argument, then, it must come from the assumption of a cladogram more like the following: primates / \ ... old-world monkeys / \ African Non-African / \ / \ monkeys apes monkeys apes / | / \ / \ ... baboons Gorilla Pan Pongo Homo / \ chimp bonobo (Many others omitted, obviously.) For this to be true would require more than just a reevaluation of the human lineage during a period variously estimated as from 3-12 My ago, but a rather severe shakeup of the entire "tree" of primate evolution. Frankly, I see an argument that depends on (as opposed to arguing for) such a serious upheaval in standard theories to be one of the primary indicators of a crackpot. (Does this remind anyone of Velikovsky?) Since, as I noted, there are a number of people who I have reason to believe not to be crackpots (e.g., Bill Calvin, Herb Huston, Paul Keck, and others) who seem to be supporting or at least not dismissing the AAT, I have to wonder if it is I who has missed the boat. I don't see how my analysis could be that far off, but neither have I seen the details of the baboon marker gene argument. What could Morgan have been thinking of that would have caused the human lineage to have lost the baboon marker gene simply by virtue of having been isolated from the African mainland? In the absence of such a factor (mechanism please) how can the argument be taken seriously? If I am misguided, please enlighten me. -- Paul Neubauer 00prneubauer@leo.bsuvc.bsu.edu 00prneubauer@bsuvax1.BITNET 00prneubauer@bsu-ucs.UUCP neubauer@bsu-cs.UUCP

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