|
Morris Goodman pioneered the introduction of molecular techniques
into systematics and had a significant impact on the development
of molecular systematics, especially as applied to primates.
The following is an edited transcript of an
intervew between Morris Goodman and Joel Hagen. The interview
was conducted on July 28, 2004 in Detroit, Michigan.
Interview Table of Contents:
Personal Background
Hagen: Maybe we could start out with some
background information about you. You were born in Milwaukee?
Goodman: Milwaukee, Wisconsin, yes, in 1925,
and I remember very much the Great Depression. We were strong
believers in Franklin Roosevelt and the New Deal and during
my high school years, near the end of them, I became interested
in how societies have evolved over human history. I think that
we’re trying to explain why I’m an evolutionist.
I would say it was first this interest in the social situation
we were in that made me very receptive to the concept of biological
evolution, when I learned about biological evolution. I can’t
remember when I first heard about it.
Hagen: Did this interest come from formal schooling
or was this something that you picked up through your experiences
in the Depression?
Goodman: In high school, I guess. There were
some teachers, who were socially conscious and recommended a
book to me that sort of roused my interest. I think it was by
the Dean of Canterbury who was called the Red Dean of Canterbury
[Hewlett Johnson]. I mean those were times when people would
question the nature of the social order we were in because of
the Great Depression and other kinds of problems. That of course
involved the next big thing in my life. During my first year
of college, which was at University of Wisconsin in Madison
from the fall of ‘42 to the summer of ’43 I enlisted
in the air force. Then when the academic year was over I was
called up so I ended up in the 8th Air Force as a navigator.
I remember the missions that we flew over the continent and
one in particular was over Berlin. The plane was hit by flak.
So we dropped out of formation and headed for Poland because
the Russians had already moved past Poland. But it developed
that the flak hadn’t that much disabled the plane so the
pilot figured we could get back to our base in England. What’s
memorable is that the navigation depended on my instructions
to get back. So that’s why I remember it. [Laughing]
Hagen: And you were in the air force throughout
the war?
Goodman: Yes, but the part in combat, or in
the European theater, our base was in England. That was either
in January or February that I arrived, sometime during the winter
of 45. So, it was the last few months of the war. They [Germany]
didn’t have many fighter planes left, but they did have
a lot of flak.
Hagen: After the war you returned to the
University of Wisconsin, can you tell me about your education?
Goodman: I probably should mention, as long
as it’s personal things, while I was still in the Air
Force, when the war in Europe ended in May, most of my group
was sent to North Africa, to what was to be a staging base to
go to the Pacific. But a few were picked to go back to the States
and I was lucky to be one of those. They sent me to Ellington
Field on the outskirts of Houston and that’s where I met
my wife-to-be and we got married in ’46. So that’s,
I guess, quite notable. I had already returned to the university.
That was in the Winter/Spring term when I restarted as a sophomore
and had a variety of courses. I hadn’t yet been committed
to a career in science but amongst the courses that I took was
comparative anatomy. I found that quite interesting and the
teacher of this course, professor Harold Wolfe, asked me if
I’d like to be a research assistant of his so I said,
“sure.” And that’s how it all developed --
my entry to the field of science.
Beginnings in Biochemistry and Immunology
Hagen: So you majored in zoology is that
correct?
Goodman: Yes, majored in zoology and minored
in biochemistry.
Hagen: And then you continued for a Masters
and PhD at the University of Wisconsin. Can you tell me about
the topic of your research and who you worked with?
Goodman: Sure, actually my Masters, proved
to be a topic that is close to one of the things I’m considered
to have helped initiate: the field molecular systematics. It
was using the antibody-antigen precipitin reaction to study
relationships among different species and in this case it was,
I think, a bovine species. My professor, Harold Wolfe had been
a student of Alan Boyden at Rutgers University, and Boyden was
known for his work in comparative serology. That field traces
back to -- the one name that sticks out is – [George]
Nuttall, and his famous monograph in 1904. In any event, I was
familiar with this field from my Masters degree. For my PhD
degree, it was about this antigen-antibody precipitin reaction.
They had used, in those years, something called the ring test
where let’s say you made your anti-serum to the serum
of a cow. Let’s say you made it in a rabbit or a chicken.
Wolfe had a great interest in making antibodies in chickens.
And you would layer the cow serum above an aliquot of the anti-serum
and if there was a reaction you’d get a precipitate between
the two. Way back in 1918, [it was] found that if instead of
saline, which is 0.9 % sodium chloride, you used 1.8 % sodium
chloride you got a better reaction. So, Wolfe wanted me to study
what was going on here. So my PhD had to do with varying the
salt concentration and seeing the affect on the precipitin reaction,
(aside from other physical factors I looked at). With the bird
anti-serum each increase in the salt concentration gave a better
reaction. That apparently has to do with the physical/chemical
properties of the bird immunoglobulins. So, that got me into
the literature on protein chemistry and so broadened my interests.
Then I went to Cal Tech for a NIH post–doctoral fellowship.
Hagen: who were you working with there?
Goodman: There were two sponsors. One was Ray
Owen, who not too many years before had been a professor in
the genetics department of the University of Wisconsin in Madison.
He became famous in the field of immunology for immunological
tolerance working with twins of cows, I believe. So, he was
one sponsor. The other was Dan Campbell who was working with
Linus Pauling’s division of chemistry. Dan Campbell was
an immunochemist. In the end, I did a project with Dan Campbell
on sickle cell hemoglobin, normal hemoglobin, and Cooley’s
anemia hemoglobin (which is predominantly fetal hemoglobin).
We actually were able to detect a huge antigenic difference
-- this was not surprising -- between the fetal and the adult
hemoglobins, but also (a noticeable difference) between the
sickle cell hemoglobin and the normal hemoglobin. Of course,
Pauling became famous for his ideas on molecular disease using
sickle cell hemoglobin as the model. And there was Alex Rich
there [at Cal Tech], I believe, and Harvey Itano. So I got the
hemoglobin samples from scientists who were there in the chemistry
division and that study picked up some recognition, and I guess
engendered an early interest on my part in hemoglobin.
Hagen: Could you talk a little bit about
your interest in evolution at that time?
Goodman: I’ll tell you [I] was much more
faithful in going to seminars than I have been in recent years.
It seems I have so many different things to do I can hardly
afford to go to this seminar and that. But as a post-doc one
of the things you look forward to are the seminars. Most of
them at Cal Tech and the departments or divisions I was in,
would have had to do with molecular biology and molecular genetics
so I did get some grounding in these areas while I was at Tech.
I could have stayed a lot longer -- Campbell thought I was stupid
to leave -- but I did at the end of the year. In any event,
the interest in doing something in the field of evolution became
awakened back in around 1957-58. After leaving Cal Tech I was
a research associate working on glomerulonephritis at the Medical
School at the University of Illinois. That medical school is
in Chicago so that again broadened by background on things like
autoimmune disease, but it wasn’t really evolution. Then
from there I moved to the Detroit Institute of Cancer research.
The main contribution I made there for several years was to
produce antisera to purified plasma proteins and then use the
antisera to measure the levels of these proteins in patients
with different diseases, but in particular different carcinomas.
In some cases the quantity of the protein we could measure would
increase as the disease worsened, and if there was a remission
it would go down. So that was of some interest, but in any event
somehow I thought that you should be able to do something more
basic. There was a colleague of mine, he was the chief pathologist
at the veterans hospital. Morris Wilson was his name. He died
back around ’59 or so. He and I lived in the same neighborhood.
We’d take walks in the evening and discuss (he was an
immunologist also) things that might be interesting to do. So
one idea was to see if proteins that are expressed from early
on in life were more conservative that is to say, change less
among species, than proteins that were expressed later in development.
To test this idea with albumin vs. gamma globulin (which is
now called 7S immunoglobulin) we needed to get a panel of primate
sera. The federation meetings [FASEB] that year were held in
Chicago. Usually in those years they were in Atlantic City,
but that year they were in Chicago and we made contact with
a Doctor [George] Rabb who was the curator of mammals at the
Brookfield Zoo. We went on and visited with him and after that
he began sending us samples of mammalian plasma or sera, and
among the samples were those from other primates such as the
gibbon (that was our first ape sample). I didn’t really
get a chance to do anything with it until I moved to the medical
school in ’58. Morris Wilson had already started working
on it. He was using rabbit anti-serum and I used chicken anti-serum.
We did get some very good results. My early publications recorded
these results, publications around ’61, ’62 and
so from there ….
Hagen: I’d like to talk about those papers
in a minute but could you just briefly tell me about the move
from the cancer research Institute to the medical school?
Goodman: Well, I don’t want to offend
anybody, but at the Cancer Institute I was hired as a research
associate and the director of the Cancer Institute seemed to
feel that I was his property, (so you have to be careful how
you report this), and so on all my papers until the last one
he was co-author. But in the last study I did, when I went ahead
and wrote it without him as a co-author, he was very offended.
So, I figured I’d move somewhere else to find another
position. And they fixed up something for me down here at the
medical school. What was perhaps relevant scientifically, it
was a reflection that the times were less scary for a scientist
than they are today . . .[interrupted by phone call].
Hagen: We were talking about your move to the
medical school…
Goodman: Yeah, well the thing was, I felt the
need to think about what it all meant and come up with some
ideas and write them up. And I just spent weeks to months doing
that and I think (laughing) I irritated my department chair
at the time. But I just went ahead and worked on it (the publication
in ’61). Well, first I presented the material and my thinking
about it at a conference on biochemical anthropology that Stan
Garn had down in Yellow Springs, Ohio where Antioch [College]
is. But there was also some institute of human growth and development
there that Stan was in charge of. That’s where I first
presented the thought about neutral mutations and things along
those lines. So, I don’t think that a young scientist
would feel, it depends on the field (in your field you would
have to think of what you want to write up and then write it
up), but if it’s in biomedical research it would be somewhat
unusual just to be spending all afternoon thinking about something.
Primate Systematics and Evolution
Hagen: I was going to ask you about doing
the type of research that you did, in terms of primate systematics
and evolution within the medical school context. Wasn’t
that unusual?
Goodman: I don’t know. Being quite frank
(that may not be the best way to be [laughing]) it was of interest
to others. The papers were of interest and word of mouth spread
about some of our findings, so I was invited to several symposia.
At the one held by the New York Academy of Sciences, in the
spring of ’62, I first proposed that chimps and gorillas
should be removed from the Pongidae and placed with humans in
the family Hominidae. That was picked up. I was interviewed
by a reporter from the New York Times and that made a big splash
at the time. Of course, some people here were very happy about
that because Wayne [State University] hadn’t been receiving
much publicity. So I guess from then on if there had been any
feeling that I was not doing biomedical research -- but I don’t
think there was, because I mean this wasn’t the only thing
I was working on. So I didn’t have any troubles.
Hagen: OK, I wanted to talk about that meeting
at the New York Academy Sciences in a minute but before we do
that could we talk a little bit about how the techniques that
you were using with Morris Wilson, how that fit in to comparative
serology more broadly.
Goodman: I think the importance is that we
could visualize reactions due to individual proteins. Often
of course, because we could make our anti-serum just to a purified
protein, but even if you made your anti-serum as to a mixture
of proteins you would get separate precipitin lines in the gel.
Each line would represent a subset of the mixture of proteins,
but not a single protein. So, the nature of the method, allows
you to get more accurate results. See, if two species were very
similar to each other, you would end up getting these reactions
of identity. The two precipitin lines would merge with each
other. But if one species had diverged away from the species
to which you had made the anti-serum (we call that the homologous
species), then you would get a spur. The original work of Nuttall
was much cruder. But more important than that is he didn’t
really relate it to current knowledge. It wasn’t known
in his day how genes encoded proteins and things like that,
but I could go from these immunological reactions and deduce
genetic relationships and generalize from it. So, I felt much
more confident in making the proposal [about primate relationships]
that I did, and, of course, with that a fair body of data to
back us up. I think it was a time when the knowledge had accumulated
and it was right to put it together and draw some conclusions
from it.
Hagen: Maybe we could talk about the two meetings
where you presented the data and you argued for reclassifying
the primates.
Goodman: I don’t recall getting any people
descending on me with negative reactions at the first meeting.
Maybe that emboldened me for the second meeting which was the
more deluxe one, more elitist one, at Burg Wartenstein run by
the Wenner-Gren Foundation for Anthropological Research (The
photograph to the right is of Goodman from this Wenner-Gren
meeting). Burg Wartenstein is a castle. I think it’s
been sold now a few times but the Wenner-Gren Foundation had
purchased it a few years before the meeting I was at and that
was their summer meeting place for select symposia. Somehow
I got invited. Sherwood Washburn had apparently known about
me and so he invited me to come and then he asked me for some
other possibilities because he wanted the molecular area represented.
So I suggested Emile [Zuckerkandl]. Emile came up with the term
“molecular anthropology,” so that was the first
use of that term. Gaylord Simpson and Ernst Mayr and Dobzhansky
were there. They were the leaders of the neo-Darwinian synthesis.
There were about 8-9 others, I guess. I guess my paper stirred
his [Simpson’s] ire the most. I think, maybe it was his
interest [in primate classification]. Put it this way, I thought
Gaylord Simpson would welcome the type of proposal I made because
he was one of the major sources of my knowledge of systematics
and evolution. He had made the statement about how it would
be priceless data to be able to map the stream of heredity.
So I figured I was starting. My results were in that direction
of mapping the stream of heredity and here I was meeting the
thrust of Darwin’s point of view to reflect the results
in a classification rather than to keep a classification that
did not depict which creatures shared the most recent common
ancestor. Simpson didn’t like tampering with the existing
classification. He authored a paper here [Sherwood Washburn
(ed.), Classification and Human Evolution]. In an addendum to
his paper, he gave his reasons why we should stick with the
old classification and not go along with the proposal of Goodman.
He added an article in Science about it a year later. He got
some mileage out of this, and this has been seized upon through
the years by those who liked the old system of classification.
Hagen: Can you talk a little but about the
interaction at the meeting itself between you and Zuckerkandl
and the leaders of the modern synthesis
Goodman: I think Emile and I and Harold Klinger,
he had chromosome data, so the three of us got along quite well.
I think we were the only three that did not have the traditional
morphological data to talk about. Klinger had chromosome data
and Zuckerkandl had this hemoglobin fingerprint data, and I
had the immunological data plus the starch gel electrophoresis
data. As I recall the three of us got along very well with each
other. In fact Zuckerkandl wrote a long addendum also and he
kept referring to similar views that were presented by Morris
Goodman.
Hagen: During that meeting there was what
Zuckerkandl referred to as a restricted meeting between the
three of you and Dobzhansky, Simpson, Mayr, and maybe one or
two others. I think there were about 8 in this group. Do you
recall that meeting and what went on?
Goodman: Well. I think the idea was to, somehow
[chuckles], my memory is not as good as it should be, but I
do recall there was that meeting. The details I don’t
remember other than I think Zuckerkandl undertook to write it
up as part of his paper.
Hagen: Do you recall the tone of the meeting?
Goodman: Yeah, I see what you’re getting
at. I was a bit taken aback, to be honest, that the leaders
in the field of the new synthesis didn’t like my proposal
to change the classification. Though they did accept the data
but not fully in the sense the actual immunological data were
more indicative of a three way split. So Simpson did accept
that chimp-gorilla-human were most closely related, but he had
chimp and gorilla very closely related. But, then he had this
mental construct of entering the new adaptive zone and a huge
degree of divergence on the lineage that entered the new adaptive
zone (the ancestors of humans). He had a nice little picture
depicting this idea. But I think the traditional people still
were interested in what the possible significance of this molecular
data was all about, and maybe that was part of the reason. But
there were -- there must have been -- disagreements expressed
between participants and I think our subcommittee was charged
with trying to define this and maybe resolve some of this, if
we could. So, both the molecular advocates plus the traditional
evolutionists got together to see what could be done.
Hagen: You corresponded a bit with Simpson
and you were with him at these two meetings. Did you interact
with him other than that?
Goodman: No, not really. I did correspond with
him. I certainly respected his opinion and in a way I somewhat
tried to accommodate my thinking to his point of view. But once
I discovered the Hennigean point of view I figured that I wasn’t
really that far out on a limb. So I never retreated too much
then. I gave back full force [chuckles] after that. I certainly
respected his [Simpson’s] great breadth of knowledge,
and also he was a very fluent writer to a broader audience.
You could understand what he was saying even if you didn’t
agree with it all. So, if I were to criticize myself at all,
(the ideas that I was pushing in that ’61 paper and for
several years thereafter), the main criticism I would have is
that I had more or less accepted the thought that there is progressive
evolution from less organized to more organized and more complex,
and that humans are at some sort of pinnacle. I don’t
think I have this view anymore. I guess complexity depends on
how you define it. Maybe in the nervous system. We could probably
find evidence that our nervous system has a greater number of
cells.
Hagen: With that in mind could you talk a
little but about how reading Le Gros Clarke’s book, the
The Antecedents of Man influenced you. You referred
to that book quite a bit and that book has a lot of Simpson’s
thinking in it.
Goodman: When I first entered this field of
using primates to look for proteins that evolved at different
rates, I became interested in what was known about the primates.
So, Le Gros Clarke was a good source, at least pretty readily
accessible. There were a number of other books that I read,
but I liked his account of placentas. The idea I had then [shared
by Le Gros Clarke] now seems to be blown apart. It looks like
the ancestral placenta was hemochorial, at least in the crown
group of mammalia [laughs]. That’s ok, what can we do
about it? In any event…
Hagen: When would you have read Le Gros Clarke’s
book? It was published in 1959.
Goodman: Probably 1959 or ’60. Certainly
by ’61. I discovered, or blissfully assumed, that it was
cut and dried what the taxonomic relationships were and that
they reflected genealogy. I discovered even from reading Le
Gros Clarke, in particular, because he dealt specifically with
primates, but also in Simpson’s Principles of Classification
and A Classification of Mammals (the section on
primates) backed up what Le Gros Clarke had to say in that there
were many questions. There were then, and now I think there
are many fewer questions. But certainly at that time there were
many questions as to what the correct genealogical relationships
were, which were correct phylogenetic relationships which they
[Simpson and Le Gros Clarke] tended to treat as a somewhat separate
question from how to classify these creatures. I mean it was
something they were interested in, but they didn’t seem
to feel it had a big impact on how they should classify them.
In any event -- once I saw that it was not cut and dried --
I thought well, gee, these [studies] are all the more important
because they are going to help work out what the correct relationships
are. I think they [Simpson and Le Gros Clarke] had a big influence
on my thinking but more because they pointed out some problems
and they stirred up my contrary spirit so I didn’t accept
them when it came to classification. I didn’t feel I had
to accept their formal classification if the molecular results
were pointing in a different direction.
Hagen: I was just going to ask if you would
respond to a remark that I found in a letter from Simpson it
was actually written to Alan Boyden. This is in 1972, and he
describes you as “an old friendly antagonist.”
Goodman: No Kidding? Now who said this?
Hagen: Simpson.
Goodman: [laughing] Oh, did he?
Hagen: So you recall your interchanges at
those meetings as being friendly?
Goodman: Yes, certainly
Hagen: Okay
Goodman: I’m not a brash sort of person.
I respected his position, and he didn’t agree with my
idea and vigorously opposed it, but otherwise I don’t
think he held anything against me and he was friendly [laughing].
Hagen: There certainly have been some molecular
evolutionists who have been interested in phylogenetic analysis
without necessarily being interested in classification. Could
you talk about how your interest in formal taxonomy developed?
Goodman: It was largely because of the discovery
that there were all of these questions as to who is related
to whom among the primates. As I mentioned, initially I thought
just looking at the formal classification would answer the questions
for me, but then when I read Le Gros Clarke’s and Simpson’s
views on the matter I could see that the formal classification
that existed at the time would not reveal the correct relationships.
It would be in the general ballpark, it would certainly be better
than nothing. So, I guess that’s what roused my interest
and then I discovered there were these different schools of
taxonomy that had quite different principles. I still feel,
as I expressed in the proceedings paper [PNAS 101(2004):
2957-2962], my co-authors and me, that when it comes to humans
this old idea of Aristotle, of a great chain of being (it’s
not just humans) has permeated all of taxonomy. Another way
of expressing a great chain of being is the scala naturae, and
more often, it’s just called the grade concept. So you
could group things if they’re supposed to be in the same
grade. You can group them together, but it’s really nebulous
what a grade is, and it’s subjective. So I think that
somehow this didn’t strike me as real science the way
a lot of taxonomy was practiced. It intrigued me, but I’m
not a professional taxonomist. But I think I know enough about
science and what we want out of the classification, or what
we should want, to feel uninhibited, in proposing certain revisions
where I have some knowledge. Another area, that our lab helped
push along quite a bit (and some leaders in the current studies
have been post-docs here) is the broader field of mammalian
taxonomy. That’s a somewhat harder nut to crack than relationships
among the primates. But a hell of a lot of the progress has
been made and we have a much clearer picture of the larger relationships.
Larger in the sense of that part of the taxonomic hierarchy
that would be involved. Which creatures belonged in an order,
how the different orders would group together into super orders
and cohorts and whatever they want to call them. There is now
a picture emerging of the order of branching among all of the
Mammalia, which is quite a bit different from the way Simpson
saw it. They used to refer to a grab bag order or garbage bag
order -- I forget the term used -- for the Insectivora, a hodgepodge
of creatures, small little insect-eating creatures, that didn’t
all necessarily belong together phylogenetically. There was
a lot of that kind of stuff in mammalian classification. That’s
being revised largely on the basis of molecular data.
Hagen: Throughout the 1960’s and actually
into the early 1970s you refer to cladistic classification,
but it in a very general sense. When and how did you become
aware of the formal cladistics in the sense that Willi Hennig
and his followers used the term?
Goodman: I would think, I ought to look at
my own papers and see, I would be surprised if it wasn’t
during the ‘60s sometime, but it could have been in the
70’s. That would be something to do, I have a collection
of my papers, year by year. I guess the paper I wrote [Molecular
Phylogenetics and Evolution 5 (1996):269-285] didn’t
specify the year.
Hagen: It said the late ‘60’s.
Do you recall how you became aware of the controversy between
the cladists, numerical taxonomists, and evolutionary systematists?
Goodman: I was a member of the Hennig society,
and I used to enjoy going to the meetings.
I used to go to the Society for Systematic Zoology meetings.
I was also with Society for the
Study of Evolution. Certainly, that must have been an issue
at society meetings.
Molecular Data
Hagen: During the early ‘70s you started
using sequence data. What happened to the serology? Did you
stop doing that?
Goodman: No, I had several PhD students who
had started with me and they kept going, I think our last paper
was in the ‘80s. It had to do with maybe the lemurs and
new world monkeys. So students from anthropology during those
years would use the immunological approach, also some students
from biology. Throughout this time we were already analyzing
the amino acid sequence data. For hemoglobin, I collaborated
with Gerhardt Braunitzer, who was the leader in the field of
hemoglobin sequencing, and also with Genji Matsuda. We had a
lot of hemoglobin sequencing on a number of different species.
So we had a lot of hemoglobin data to analyze.
Hagen: Can you tell me a little more about
the hemoglobin work and what came of it?
Goodman: I think we were the first to get hard
evidence of Darwinian evolution. The paper was published in
Nature [253 (1975): 603-608]. The three dimensional
structure of hemoglobin had been very well-analyzed by Perutz.
From his analysis of what each position in the globin molecule
was involved in -- what its function might be -- I made a list.
Aside from the positions at the heme binding sites which are
very anciently conserved there are a set of positions that are
implicated in the so-called cooperativity between the subunits,
that are responsible for unloading oxygen in the tissues. It
facilitates the unloading of oxygen from the normal state where
it would go slowly and then go more rapidly. In any event, there
were several categories of positions that were involved in this
and we found in particular there were the alpha one-beta two
contact sites, also the so-called Bohr Effect sites. We found
that with the emergence of the jawed vertebrates we could make
a phylogenetic tree that encompassed the available sequence
data on vertebrates plus the homologous globins in invertebrates
and even in plants (leghemoglobin), so there was quite a broad
range of taxa or clades represented by this hemoglobin tree.
In any event, we could go ahead and reconstruct ancestral sequences
at the nodes of the tree. We found that the sites concerned
with cooperativity showed a big burst of change with the emergence
of the jawed vertebrates and kept going on this change until
the amniotes emerged. Then these sites became very slow evolving,
even more conserved than the heme binding sites. That‘s
what we emphasized in the paper. I think that was one of the
first to use the concept of using this three dimensional structural
data to compare for a protein -- or a protein family -- the
changes in certain sites both early and then later in evolution
and to draw some conclusions as to whether we thought they were
neutrally evolving, or under stabilizing selection, or at some
stage under positive selection. I think that was one of the
first papers to show that this could be done in a meaningful
way. Now it’s rather commonly done. We came up, a few
years later, the paper was in Nature, [298 (1982) 297-300],
with using nucleotide sequences of the globins, not just the
amino acids sequences, and comparing the non-synonymous changes
to synonymous. That is to say the amino acid changing to the
amino acid unchanging substitutions. We provided some evidence
that when there was a big burst of non-synonymous change that
seemed greater than what you’d expect in a neutral state
then you might draw the conclusion that positive selection was
going on. So, we were involved in some of these early efforts.
Neutral Molecular Evolution and the
Molecular Clock
Hagen: Can we talk a little bit about the
neutral theory and how you responded to the King and Jukes paper
in 1969?
Goodman: I don’t remember seeing King
very often. I think it was tragic that he died, maybe from a
malignancy, I don’t remember anymore. But Tom Jukes, I
used to visit with him frequently when I was out in California.
He was very friendly. I think that [paper] was a nice contribution,
but I was always a little bit put out that people ignored my
original speculations that I published first in ’61. There
I tied it to when in evolution you would expect lots of neutral
mutations. At least I had the idea of neutral mutations in proteins.
Usually that’s not cited anywhere except by me [laughs].
I guess the neutral theory is based on genetics and the mathematics
of population structures. So, I don’t want to take away
any credit from it. It’s kind of a null hypothesis. We
challenged it’s applicability to protein evolution starting
from around ’75, if not earlier -- but definitely from
’75 on. So maybe in ‘69 I didn’t have any
huge reason to want to contest King and Jukes.
Hagen: Was the hemoglobin research that you
were describing a few minutes ago an outgrowth of that sort
of controversy?
Goodman: Yeah, I think so, because I could
see that it [our hemoglobin results] was relevant to the controversy,
and also I never liked the idea too much of a universal molecular
clock. That was there in ’71, we had a paper in Nature
that was opposed to the idea of a universal clock.
Hagen: Could we talk a little bit about Sarich
and Wilson’s papers in that regard?
Goodman: Well, I guess I didn’t like
them using me as an example of being misled, but part of the
criticism was merited. They seized upon summary sentences of
mine in my ‘61 paper where I naively took as given a point
a separation of gibbons from the rest of the primates -- the
absurdly ancient (apparently) date of 40 million years ago.
It was based upon what the paleoanthropologists at that time
thought. Apparently modern paleoanthropologists would no longer
go back that far, and the molecular clock approach doesn’t
go back that far either. It only went back, I think, about 10
million years. It depends on how you use the global molecular
clock as to what you come up with. So, we’ve come up with
the approach called local molecular clocks, that was a good
idea, and it is a good idea. It’s been transcended --
without us getting too much credit for pushing it in the first
place -- by computer programs that are more sophisticated than
our simple hand calculations were, and it gives you a statistical
range and so on. I’m somewhat digressing from whatever
information you want from me at this point [laughing].
Hagen: In your 1971 paper with Moore [Systematic
Zoology 20 (1971): 19-62], you contrast your idea of deceleration
in evolution with Sarich and Wilson’s constant rate clock.
Could you comment on your initial reaction to their claim and
how that became resolved in terms of your work?
Goodman: Yeah, I think we always got along
well with each other personally. We didn’t make a federal
case out of this difference on whether there are global molecular
clocks or not. In criticizing my claim that there wasn’t
a global clock they would cite certain times that I used a very
naïve acceptance of what the fossil people said. Time has
been more on their side than mine, so I wouldn’t stick
with that any more. In fact, not too many years later I accepted
different dates and still found the slowdown. It was more that
idea that I stuck by, that there was a slowdown. That’s
still controversial. Scientists such as [Simon] Easteal think
it’s a crazy idea and apparently will write some pretty
nasty things about Goodman because he has this idea of a slowdown,
but others in the field don’t think it’s so crazy.
There is a lot more acceptance of the thought that there is
a difference between the murid rate and the anthropoid rate,
the murid rate being a lot faster than the anthropoid rate.
That seems to have a lot of support. The slowdown idea is, I
think, is more accepted than not. I could be wrong.
Hagen: Does that apply specifically to albumin
or proteins more generally?
Goodman: Actually to the rate of occurrence
of de novo mutations and therefore most apt to be expressed
by non-coding DNA and by synonymous substitutions. By those
kinds of substitutions that are likely to not come under the
purview of natural selection. That is to say are selectively
neutral. We first pushed the idea a bit with protein evolution.
I think we disbanded pushing it too hard because there are enough
examples where there have been speedups. In fact, the group
of proteins I’ve been working with the past five years
with Larry Grossman’s research group. There the evidence
is that within the Anthropoidea there’s been a speedup
of the evolution of these proteins and we attribute this to
positive selection. That’s under controversy whether its
just neutral changes -- that for some reason positions that
used to be under strong purifying selection are now released
from the previous constraints and mutations can accumulate by
random drift -- or as we like to think and martial arguments
for, that positive selection favored the changes and that’s
why they occurred in the Anthropoidea. As I say that’s
controversial and people are trying to do a studies that can
resolve the issue.
Hagen: Which proteins are these?
Goodman: Cytochrome c would be one. Aside from
cytochrome c the main proteins are in what’s called the
electron transport chain. These are multi-subunit complexes
that function in the mitochondria. There are five of these complexes
and in four of the five cases some of the subunits are encoded
by the mitochondrial genome and the rest of the subunits an
encoded by the nuclear genome. Then the encoded protein migrates
into the miotochondrion and becomes part of the complex that
is assembled within the mitochondrion. It functions there. It’s
responsible for aerobic energy metabolism. Quite a few of those
subunits show an upsurge of rates in the Anthropoidea, particularly
in the catarrhines. So that’s what we are currently working
on.
Organismal Perspectives, Genomes,
and Humanity
Hagen: You have described changes in molecular
evolution that you were involved with as a kind of paradigm
shift. If we look at evolutionary biology as a whole, how does
molecular evolution fit with other non-molecular approaches?
Goodman: When it comes to the bigger questions
we should not view molecular evolution as divorced from organismal
evolution. I think there are tremendous interconnections among
these levels of evolution. This of course is an area of biological
science that tries to emphasize the integration of the different
levels. The reason we think for reconstructing phylogeny that
molecular data is so important is because of things such as
Simpson said that it would be priceless data to be able to map
the stream of heredity. That’s exactly what the genome
sequencing is allowing. But it’s only in its infancy in
terms of the amount of genome data that we need to adequately
map the stream of heredity. I think it’s moving along
with the primates pretty well. It probably will influence the
nature of biology for the next 50 years or so.
Hagen: Another change that you have described
as a new paradigm is the way humans view themselves. Would you
care to speak to that?
Goodman: Yeah, very much so. It’s a little
bit disappointing, the reaction to the chimp genome in that
the emphasis has been -- among a number of investigators --
that this is an opportunity to put your finger on what is unique
for humans and that this is of overriding importance. I suppose
that even to do that you need more than the human and chimp
genomes. You need the gorilla genome in on this story to be
able to put your finger on the genetic changes that were in
the human line and those separate ones that were in the chimp
line. I think in the big picture what is being ignored is how
much we hold in common with other creatures, in particular the
chimp, next with the gorilla. I think more emphasis ought to
be on that. Also what’s unique to the chimp could be quite
useful to humans and should be just as important as what’s
unique to us. For example, in AIDS the chimp seems to have natural
resistance. Certain proteins have been implicated -- the genes
for these proteins. So, this is something that ultimately, the
pharmaceutical industry ought to be able to make use of to see
what could be done in treating humans with AIDS or to try to
protect us from AIDS. Apparently the surviving chimps have these
genes that give them protection against AIDS. There must be
other diseases, too. Again, this is a very narrow approach,
but I can see that humans have a right to be concerned with
their own welfare. Why not? But in the bigger picture, we want
to preserve the natural environment, definitely preserve our
closest relatives, as well as many other species as possible,
rather than engaging in practices that cause mass extinction,
including that of the chimp and the gorilla. They are threatened
with extinction in the not so distant future unless something
can be done to preserve their habitats. I guess this gets you
back into politics, but scientists should be concerned with
these questions.
Hagen: Do you think there’s an irony
in the fact that our knowledge of how closely related we are
to these other species coincides with a time when they really
are in danger of extinction?
Goodman: I think there is an irony but maybe
it’s part of the wake up call that’s going on. I
guess there have been huge crises in human history, but some
of the biggest ones have been here in the century just past.
There was the First World War, the Second World War, and somehow
the whole human species is in crisis, I think. Maybe there is
an opportunity to reverse the tide and to save ourselves. We
have to save a lot of other species, as well. I think we should
realize that destroying the natural habitats, I guess for more
profits at some level, that it’s going to threaten our
species as well. So, something has to be done. But if you have
an evolutionary perspective you can well imagine that we may
become extinct and that there is nothing sacred about us surviving
forever. Now I’m going back to something I believe in
strongly. I think we can solve these problems, but we also can
fail to solve them. We’ve been living since the First
World War, and especially the Second [World War] with the atomic
bomb, with this knowledge that life can be extinguished in a
massive way.
This page was created and is maintained by Michael
Dietrich.
|
