Out of Africa

L.A. Moran lamoran at gpu.utcs.utoronto.ca
Mon Nov 18 23:02:36 EST 1991


In this thread we are discussing the hypothesis that modern man (Homo
sapiens sapiens) originated in Africa and spread out from there
replacing indigenous humans who already inhabited Europe and Asia. It
is important to distinguish this idea from the hypothesis that the GENUS
Homo originated in Africa.

When I suggested in an earlier posting that the molecular data in support
of the Out-of-Africa hypothesis was weaker than I had realized Jones Maxime
Murphy (morphy at cco.caltech.edu) wrote,

     "Are you kidding? Non-African scientists have strenously resisted 
      the notion of an African genesis of Man. It is simply the crushing 
      preponderance of the evidence that has overcome the overabundance 
      of "caution" (negrophobia) that characterized research on human 
      origins."

I believe that Jones Maxime Murphy is confused about the distinction between
the two theories that I mentioned above. Either that or he is confused about
the quality of the data ("crushing preponderance"...gimme a break!). James
Maxime Murphy also attempts to establish a correlation between racists
and those who question the Out-of-Africa hypothesis....he should be ashamed
of himself.

In trying to understand the anthropological data I said,

     "There seems to be good evidence that Homo has been present in 
      Eurasia and Africa for over one million years and that the 
      transformation to modern Homo sapiens sapiens occurred 
      simultaneously in many parts of the world."

Jones Maxime Murphy replied,

     "There is no evidence to support this theory. This is simply racist
      wishful thinking posing as "science", an all too frequent occurrence
      in the study of human origins."

Thank you for clearing up this little problem for me, Jones. I had not 
realized how pervasive and clever these racists were! They almost had me 
fooled! Thank God that there are politically correct people such as yourself
who can recognize good science from bad science (-: (-:  By the way, in case 
the smileys aren't enough I want to make it perfectly clear that your
attitude disgusts me.

With regard to the linguistic evidence I said,

     "I am not aware of ANY linguistic evidence that supports the 
      Out-of-Africa theory...The correlation between language
      and genetics that is being pushed by Cavelli-Sforza (5) seems
      to me to be mostly trivial."

and Jones replies,

     "That is a value judgement about a rock-solid conclusion that you 
      appear to find unappetizing. It has no net semantic content and is
      therefore itself trivial.

      The C-S article does not address the question of monogenesis or 
      polygenesis of language *at all*! It merely points out the 
      correlation of language families as they now exist with the 
      reconstructed "family tree" obtained from mitochondrial DNA. Such 
      a correlation, coming from vastly different aspects of humanity, 
      is hardly trivial, in my opinion."

I have no idea what Jones is referring to when he mentions a rock-solid
conclusion. Jones appears to have read a different Cavalli-Sforza article
than the one that I read. My Scientific American says, "Genes, peoples
and languages have thus diverged in tandem, through a series of migrations
that apparently began in Africa..." Also, my Scientific American article
shows a dendrogram which is constructed from analysis of nuclear genes
NOT mtDNA. This distinction is very important because it would be impossible
to correlate language with the mitochondrial dendrogram.

I also said,

     "A lot of genetic "evidence" seem to me to be highly suspect.
      It relies more heavily on imagination and unproven assumptions 
      than on real science."

and Jones replied,

     "This is interesting. I'm a physicist. I see real science here. 
      Who are you and what is your claim to decide for the rest of us 
      what is "real science"?"

I am a molecular biologist whose main research interest is molecular
evolution. My lab sequences DNA and we construct molecular dendrograms
in order to understand evolution. I do not claim to decide for the rest
of you what is "real science", I thought that I made it very clear that
this was my personal opinion. Jones, do you have some kind of hidden agenda
in attacking me? (I also made it clear that the "evidence" I was referring
to was NOT in the papers that I choose to discuss.)

I questioned the data and the conclusions in the original Nature paper by 
Cann et al. and Jones Maxime Murphy said,

     "Your reading comprehension has clearly failed you. Reread that 
      article. The central point of the article was just the negative
      reply to your last question!!

      The genetic base of Eurasia is narrower than that of Africa. 
      Dramatically so. This is particularly striking considering the 
      relative area and populations of these landmasses.

      I strongly urge you to reread the article. Your prejudices have
      clearly rendered your (no doubt keen) analytical powers impotent."

Jones, you have every right to debate this issue with me and I will even
tolerate your implications that I am stupid. This is fair flaming as far
as I am concerned. You can read the other postings in this thread in order 
to gain a better understanding of the quality of the data and the conclusions. 
However, when you imply that my imagined "prejudices" are interfering with
my science you have deeply insulted me and impugned my character. You don't
even know me, how can you make such a judgement? Please be more careful
in the future or else we might get the wrong impression about your own
character!

With respect to the Cavelli-Sforza data I said,

     "As far as I can see the results may be consistant with the Out-of-
      Africa hypothesis but they are also consistant with an Out-of-
      Eurasia hypothesis."

and Jones replied,

     "The key point here is that Africans are uniquely distant from *all* 
      others. You naturally neglect to point out that intra-continental
      genetic distances in Africa are themselves comparable to inter-
      continental distances for all others, a significant fact.

      How so? How would you "rationalize" an Out-of-Eurasia scenario 
      given the data?"

The key point here is that the Cavelli-Sforza data shows a clean separation
between Africans and non-Africans. It is extremely important to note 
that the Cavelli-Sforza data is NOT the same as the mitochondrial data.
The genetic diversity of the African populations in the Cavelli-Sforza
papers is less than that of the Eurasian population (this is possibly due
to the small number of Africans). In any case the data shows that the first
split of the ancestral population was into Africans and non-Africans. There
is no logical reason that I can see for assuming that the ancestors were
in Africa or in Eurasia. If Jones can explain this to me I would greatly
appreciate it. 

I continued my questioning of Cavelli-Sforza's data with,

     "In a more scientific paper (6) Cavelli-Sforza's group doesn't even
      mention the Out-of-Africa hypothesis.... (I referred to a paper
      that was published in Feb. 1991)

Jones continues on his high horse,

     "You speciously refer to a three year old paper, written before 
      the latest analysis was completed. This is simply a dishonest 
      attempt to portray the views in the above paragraph as being 
      contemporaneous with the latest issue of Sci-Am."

I don't believe that this deserves a comment from me since I was obviously
referring to a recent paper and I was trying to make the point that what
was written for popular consumption may be an exaggeration of the strength
of the data. I am not trying to be dishonest.

I also said,

     "Rooting the tree: One could also use orangutans to root the human 
      geneological tree but this would not be considered evidence that 
      humans originated in Indonesia! I assume that the authors meant to
      say that the closest living ancestors of humans are chimps (and/or
      gorillas) and that these species also live in Africa. But this is 
      evidence in favor of the African origin of the GENUS Homo and not of
      the SPECIES Homo sapiens sapiens.  Am I confused about this? (Does
      anyone know if the fossil evidence of chimp and gorilla evolution 
      confirms that these species are confined to Africa?)"

Jones responds,

     "I have heard of no evidence of chimps or gorillas outside of Africa. 
      Chimps are particularly important, since they're our closest living
      relatives (and NOT ancestors!!!). It is unfortunate that some continue
      to rank-order existing animals as if nature as it exists today is 
      merely an evolutionary ladder leading up to homo sapiens. This is 
      absurd."

You are perfectly correct about the distinction between ancestors and 
relatives. This was a slip of the keyboard because I was thinking of the
suggestion that both chimp and human ANCESTORS lived in Africa. My error
is particularly ironic because I have campaigned strenuously against the
assumption that evolution is hierarchical and that any living organism is
more primitive than another. I have purged such references from the textbooks
that I edit and those that I write. My apologies for such a silly mistake. 

Incidently Jones, there is still some debate on whether chimps or gorillas
are our closets living relatives. I happen to favor the chimp supporters
but I would never make as definitive a statement as you made. Do you know
something that I don't?

Finally Jones closes with,

     "Let's face it, Larry. Inside of you there's a nigger, dying to
      get out."

I don't understand the point of this statement but I do not think that it
is funny. Jones seems to be a part of the politically correct movement
that seeks to find racism in every comment that doesn't conform to some
mythical standard. Because I have dared to question the molecular data
that support an Out-of-Africa hypothesis I must be a racist according to
Jones. Have we really sunk so low?

Laurence A. Moran (Larry)
Dept. of Biochemistry
University of Toronto



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