I've been thinking about this a lot: We MUST add Chimpanzees to genus homo.

[hunter]

Pan troglodytes becomes Homo troglodytes, and Pan paniscus becomes Homo paniscus.

We should also be thinking about changing our own name from Homo sapien to something like Homo vulgaris, the common ape. Looking around at all the death and destruction we have caused on this planet it's clear we are not all that sapient. Our population growth is no wiser than that of yeast in a vat, algae in a pond, or rats in a city... and we often die like them too.

I'm certain the original nomenclature was a deliberate sort of misdirection, conscious or not, to put as much distance between human beings and our natural history as possible. The very obvious relationship between chimps and humans was simply too much for our religious and racist society to accept.

As a kid looking through the books on human evolution I wondered what it would be like to share our world with close human relatives such as Homo habilis. These speculations were fueled directly by the Time-Life Books sort of science I was fed. I now realize we actually do share our world with such very close relatives -- the chimpanzees, the bonobos, the gorillas, and the orangutans.

By adding chimpanzees and bonobos to the genus Homo we emphasize our relationship to the rest of nature, and suppress all the ignorant and stupid "missing link" arguments. And most importantly, this might lead to further environmental protections for all the great apes.

It's not just the politics that motivates me, it is very solid biology.

So, what do you think?

[lazer47]

1. We already did in 2000,, his classification is GWB

[qb]

2. Sounds good to me, but I suspect a few creation "science" heads will explode

:nuke:

[hunter]

3. Good.

I'm tired of arguing with creationists.

[Hydra]

4. Too many people have a vested interest in denying that we are animals

I, however, have no problem with it. Would could all stand to be SMARTER ANIMALS, IMO.

Here's a good video to get your point across:

http://youtube.com/watch?v=a15KgyXBX24

[hunter]

5. There's also this, by Dawkins...

Gaps in the Mind

By Richard Dawkins

Excerpted from The Great Ape Project, edited by Paola Cavalieri and Peter Singer London: Fourth Estate, 1993.

Happenings are sometimes organised at which thousands of people hold hands and form a human chain, say from coast to coast of the United States, in aid of some cause or charity. Let us imagine setting one up along the equator, across the width of our home continent of Africa. It is a special kind of chain, involving parents and children, and we will have to play tricks with time in order to imagine it. You stand on the shore of the Indian Ocean in southern Somalia, facing north, and in your left hand you hold the right hand of your mother. In turn she holds the hand of her mother, your grandmother. Your grandmother holds her mother's hand, and so on. The chain wends its way up the beach, into the arid scrubland and westwards on towards the Kenya border.

How far do we have to go until we reach our common ancestor with the chimpanzees? It is a surprisingly short way. Allowing one yard per person, we arrive at the ancestor we share with chimpanzees in under 300 miles. We have hardly started to cross the continent; we are still not half way to the Great Rift Valley. The ancestor is standing well to the east of Mount Kenya, and holding in her hand an entire chain of her lineal descendants, culminating in you standing on the Somali beach.

The daughter that she is holding in her right hand is the one from whom we are descended. Now the arch-ancestress turns eastward to face the coast, and with her left hand grasps her other daughter, the one from whom the chimpanzees are descended (or son, of course, but let's stick to females for convenience). The two sisters are facing one another, and each holding their mother by the hand. Now the second daughter, the chimpanzee ancestress, holds her daughter's hand, and a new chain is formed, proceeding back towards the coast. First cousin faces first cousin, second cousin faces second cousin, and so on. By the time the folded-back chain has reached the coast again, it consists of modern chimpanzees. You are face to face with your chimpanzee cousin, and you are joined to her by an unbroken chain of mothers holding hands with daughters. If you walked up the line like an inspecting general--past Homo erectus, Homo habilis, perhaps Australopithecus afarensis--and down again the other side (the intermediates on the chimpanzee side are unnamed because, as it happens, no fossils have been found), you would nowhere find any sharp discontinuity. Daughters would resemble mothers just as much (or as little) as they always do. Mothers would love daughters, and feel affinity with them, just as they always do. And this hand-in-hand continuum, joining us seamlessly to chimpanzees, is so short that it barely makes it past the hinterland of Africa, the mother continent.

http://www.simonyi.ox.ac.uk/dawkins/WorldOfDawkins-archive/Dawkins/Work/Articles/1993gaps_in_the_mind.shtml

[phantom power]

6. maybe we should change our genus to "pan."

[hunter]

7. I thought of that...

...but it would be quite a job to change the names of all those human ancestors.

And I imagine the Neanderthals would be upset. Would you make this kid cry?



http://www.ifi.unizh.ch/staff/zolli/CAP/Main_face.htm

Some cool reconstructions, Neanderthals included:

http://www.daynes.com/fr/reconstructions/reconstructions.php

By keeping Homo you only have to change three names.

[HiFructosePronSyrup]

8. Too many anatomical and genetic differences, IMO.

Concerns about Creationists and the environment, however noble, don't warrant a change.

[hunter]

9. I'm a lumper not a splitter, and I think we pay too much attention to "anatomical differences."

Genetic studies really are superseding many of the anatomical difference we once thought important. If we draw the line at the common ancestor of humans and chimpanzees, it's really not too much to chew on.

It's already demonstrated that humans will reject other humans as kin on the basis of trivial anatomical differences, and it's very likely this prejudice has caused us to place chimpanzees outside our own genus.

[semillama]

10. What's the solid biology?

You've posted the politics, but on a strictly biological basis, I don't think it's quite that solid. The great apes are already part of hominidae, and gorillas and chimpanzees share the subfamily homininae with us.

Chimpanzees may be our closest relatives, but there's still a fairly big (and old -about 6 million years) genetic gulf between the modern Homo genus and Pan genus. We are too evolutionarily different to warrant such a large lumping. Not only are you proposing to lump Homo with Pan, but then you have to lump all the other non-Homo hominids, too, such as Australopithicus, etc.

Here's Ernst Mayr on the concept of genus:

"WHAT IS HOMO?

The early species Homo rudolfensis and H. erectus did not reach the brain capacity of the Neanderthals (1,600 cc) or H. sapiens (1,350 cc), but the increase from the australopithecine brain of 450 cc to the 700-900 cc of H. rudolfensis is almost a doubling of size and a much greater advance than the shift from 900 cc to 1,350 cc, an increase that I do not consider to be of generic value. A genus usually indicates an ecological unit, a noticeable difference in the exploitation of the environment. The designation Homo does have such a significance. It designates the emancipation from dependence on trees. Once this independence was achieved, a premium was placed on the enhancement of intelligence, provided the evolutionary unit was small enough to respond to selection. The evolutionary increase of brain size ended when selection for further increase was no longer rewarded by a reproductive advantage."
Ernst Mayr, What Evolution Is (2001), pg 235

[hunter]

11. We think too highly of ourselves. Our behaviors are entirely chimpanzee.

The toolmaking and all that other big-brain stuff is only significant for the curious layer of toxic garbage we will impress upon the geologic record. A million years from now maybe someone of a non-hominid space faring race will discover our remains and think "Wow, they even managed to spread their garbage beyond their home planet!"

I would certainly include Australopithicus in the genus Homo too. I think a lot of the impetus to explore our family tree was fueled by a conscious or subconscious desire to place as much distance between us and the chimpanzee as possible. The more names you have for various bits of fossilized humans, the less you are a chimpanzee. I'm absolutely certain some of the funding for such endeavors was born of such motivation.

When you look at the genetics of chimpanzees they have a much greater depth to their gene pool, and that's remarkable when you consider their small population. The human population, as large as it is, has about one fifth the genetic diversity of existing populations of chimpanzees. It's very clear that human evolution was accomplished by extensive pruning of our common chimpanzee ancestor's genome. We are related to chimpanzees in much the same way as domestic dogs are related to wolves.

If we were to do something so horribly unethical as to breed chimpanzees for "intelligence" and bipedalism, we could probably create an animal that was essentially human in less time than it took for for wolves to become dogs.

[semillama]

12. Again, I think you're letting the politics/sentiment get in the way of the science

Our behaviors are far from entirely chimpanzee. There's a lot in common, but to dismiss the entire range of significant behavior of genus Homo as no different from Pan is a pretty extreme position. It's not just "tool use" but the ability to consciously affect your environment, producing the toxic garbage you note, but also things such as art, music, architecture, and so on and so on. All very un-chimpanzee like behavior. The ranges of behavior, adaptability, complex culture, and capability for abstract thought are all more than sufficient to justify a separate genus for Homo, indeed enough to warrant a separation of Australopithecus from Homo. The history of scientific nomenclature and suspicions about motivations are all well and good to have, but it's not enough to through away well-developed, rational science.

In anatomy alone, the whole bipedalism/opposable thumb thing is in and of itself a pretty good reason to qualify a separate genus for Homo.

[hunter]

14. Those bipedal apes we dig up are probably not our ancestors.

I expand on the idea slightly below. Bipedalism may be an easy tool to pull out of the proto-chimpanzee genome.

"...art, music, architecture, and so on and so on" are not the underlying biology. If you raised a small band of modern humans with all the technology and society of ordinary bonobos, they'd look and live pretty much as bonobos do. How long would it be before some genius thought to make a shelter out of sticks, and would such a house increase their chances of survival, or would it simply make them easier to find by the tigers?

[semillama]

21. So, in order to force Pan into Homo, you have to throw out

the entire hominid line? Pretty big stretch there and it's not supported by the current science.

As I said before, genus status isn't just based on biology and genetics, but also on factors such as ecology, biogeography and morphology.

But even sharing 96% of our DNA doesn't make Pan into Homo, or vice versa. And it is 96%, by the way, not 98.5%. 4% of 3 billion nucleotides is a pretty hefty difference of 120,000,000 nucleotides. For comparison, we share about 60% of our DNA with mice.

As someone with an anthropology background, I think it makes scientific sense to separate two groups of apes into individual genera based on such factors as habitat, bipedalism, adaptation to specific and general ecologies, and range, not to mention a fairly hefty genetic divergence. Taking Homo out of the equation, there's still a load of difference between Pan and Australopithecus that argues for two separate genera - and that's assuming that the common ancestor for Pan, Australopithecus, and Homo could even be classified as Pan at all - it could be something completely different.

[hunter]

22. If genetically we have more in common with the bonobo than the chimpanzee...

... it really messes up our family tree.

It would be a cosmic joke on us if we've spent all this effort elucidating the family tree of Homo erectus and it turns out not to be our own... which does seem to be the case for at least the last million years or so.

Suppose Homo habilis and Homo ergaster are the direct ancestors of Homo erectus but not Homo sapien. What then? Mind you, please, I am not some freak trying to place human evolution in Europe or some other place for nationalistic, religious, racist, or egotistical reasons.

As you are well aware the fossil evidence is sparse, and restricted to areas favoring the preservation of bone. There are numerous hominid species we will never know of except for the evidence preserved in the genes of existing hominids.

Whatever our common ancestor was, it seems to have had a huge capacity for diversification. The time frames are so small, even if you place the common ancestor of humans and chimpanzees back 9 million years (which seems very unreasonable now given the genetic data), that it's clear these rapid adaptations were facilitated by the simple shuffling of genes within a very rich genome.

It's a very similar situation to that of the genus Canis. We seem to have no problems with the canine radiation of the Late Miocene, but we refuse to acknowledge in our nomenclature a very similar radiation within our own family tree.

Based on the fossil and genetic evidence we have now it seems to me that we are struggling to draw the line for the Genus Homo at any point but the beginning of our divergence from the chimpanzee, as if God Forbid we might be more closely related to the chimpanzee than makes us comfortable.



These are the footprints of a walking chimpanzee that may or may not be our direct ancestor, and they are a mere 3.5 million years old. If we were able to travel back in time and look around we would already have names for the vast majority of plants and animals we saw. If we saw the creatures that made these footprints we might first think, "wow, look, a walking chimpanzee!"

But it also wouldn't be a huge leap to include the creature in our own genus.

[TZ]

19. You do know that tool using is common outside of primates

Don't you? Birds in particular are very good tool users. As are otters. As for relationships, even though genetically chimps are the closest to us, if you look at all mammals the genetic differences between them aren't that great. Look at genetic studies that show only a few genes actually contribute to the anatomical structure.
As for behavior, dolphins and some whales actually have some very similar social structures to humans. Many social animals show similar behavior. You can also find many examples of human behavior in other animals like birds.
Also, lemurs in the primate family are fairly close relatives, but I don't think anyone would classify them in with us.
Your arguments aren't convincing to this biologist.

[hunter]

20. Here's a fun link for your exploration...

Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: Enlarging genus Homo

Derek E. Wildman, Monica Uddin, Guozhen Liu, Lawrence I. Grossman, and Morris Goodman

Center for Molecular Medicine and Genetics and Department of Anatomy and Cell Biology, Wayne State University School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201

Contributed by Morris Goodman, April 14, 2003

What do functionally important DNA sites, those scrutinized and shaped by natural selection, tell us about the place of humans in evolution? Here we compare {approx}90 kb of coding DNA nucleotide sequence from 97 human genes to their sequenced chimpanzee counterparts and to available sequenced gorilla, orangutan, and Old World monkey counterparts, and, on a more limited basis, to mouse. The nonsynonymous changes (functionally important), like synonymous changes (functionally much less important), show chimpanzees and humans to be most closely related, sharing 99.4% identity at nonsynonymous sites and 98.4% at synonymous sites. On a time scale, the coding DNA divergencies separate the human–chimpanzee clade from the gorilla clade at between 6 and 7 million years ago and place the most recent common ancestor of humans and chimpanzees at between 5 and 6 million years ago. The evolutionary rate of coding DNA in the catarrhine clade (Old World monkey and ape, including human) is much slower than in the lineage to mouse. Among the genes examined, 30 show evidence of positive selection during descent of catarrhines. Nonsynonymous substitutions by themselves, in this subset of positively selected genes, group humans and chimpanzees closest to each other and have chimpanzees diverge about as much from the common human–chimpanzee ancestor as humans do. This functional DNA evidence supports two previously offered taxonomic proposals: family Hominidae should include all extant apes; and genus Homo should include three extant species and two subgenera, Homo (Homo) sapiens (humankind), Homo (Pan) troglodytes (common chimpanzee), and Homo (Pan) paniscus (bonobo chimpanzee).

http://www.pnas.org/cgi/content/full/100/12/7181

Later genetic evidence is even more compelling.

I suspect Lucy is simply another bipedal chimpanzee, and there are a whole lot of those we may or may not be directly related to. Later on in the geologic record you've got critters like Homo georgicus that may be more of the same bipedal sort of chimpanzees.

Further explorations of the genetic relationships between chimpanzees, bonobos, and humans will be very illuminating.

I know it's would be painful for many to dismiss so much of the hard work that's gone into exploring human evolution by the morphology of fossils, but it may turn out that many of those familiar reconstructed faces are simply cousins, and not our direct ancestors. All along we may have been sharing the planet with other members of our own genus, but simple racism may have blinded us to that.

[hunter]

13. Here's a quick chart I drew:

Hah, now you get to see my glorious aspergers handwriting!



All the timescales here are very rough, off the top of my head, but there was a long period when human, chimpanzee, and bonobo ancestors were one species, diverging and recombining in such ways that for some genes various groups of existing chimpanzees are less related to one another than they are to bonobos. Evidently populations of chimpanzees would wander off, diversify, and then bring those genes back together again, thereby creating a very rich genetic heritage.

There's some really surprising stuff in the chimp genome project that may indicate human and chimp populations didn't finally diverge until about 4 million years ago. Furthermore, if it turns out we are more closely related to the bonobo than the chimp, then this would be exceptionally shocking news and put existing human lineages in some disarray -- like all the other supposed human ancestors Mr. Homo habilis becomes just another chimpanzee who went out for a walk.

[Nihil]

18. Good point

> There's some really surprising stuff in the chimp genome project that may
> indicate human and chimp populations didn't finally diverge until about
> 4 million years ago. Furthermore, if it turns out we are more closely
> related to the bonobo than the chimp, then this would be exceptionally
> shocking news and put existing human lineages in some disarray -- like all
> the other supposed human ancestors Mr. Homo habilis becomes just another
> chimpanzee who went out for a walk.

And this can be verified with our behaviour today ... intolerant and ruled
by the ignorant majority.

[phantom power]

15. I guess one question is, who would we have to convince?

I don't see this happening, but who actually makes these decisions?

[hunter]

16. Once I started thinking this way I couldn't go back.

Very much like the wolf, there was a whole lot of potential tucked away in those chimpanzee ancestor genes.

Drawing the line at simple morphological features such as bipedalism or brain size doesn't make sense. I suspect both those features arose independently a few times, which means that most of the "human" fossils we've discovered are not our direct ancestors.

The genus "homo" is probably an artificial conglomeration of unrelated threads arising from a common population of chimpanzee ancestors. We can neatly sidestep this potential problem of taxonomy by reclassifying Pan as Homo.

So far as my renaming of Homo sapien to Homo vulgaris goes, well the Latin is damned near perfect, and I enjoy poking a stick at people who appear to be stuck in a rut of conventional thinking.

[hunter]

17. Some science. A paper in Nature.

Grab the pdf here.

Daniel J. Richter, Sante Gnerre, Eric S. Lander & David Reich

The genetic divergence time between two species varies substantially across the genome, conveying important
information about the timing and process of speciation. Here we develop a framework for studying this variation and
apply it to about 20 million base pairs of aligned sequence from humans, chimpanzees, gorillas and more distantly
related primates. Human–chimpanzee genetic divergence varies from less than 84% to more than 147% of the average,
a range of more than 4 million years. Our analysis also shows that human–chimpanzee speciation occurred less than 6.3
million years ago and probably more recently, conflicting with some interpretations of ancient fossils. Most strikingly,
chromosome X shows an extremely young genetic divergence time, close to the genome minimum along nearly its entire
length. These unexpected features would be explained if the human and chimpanzee lineages initially diverged, then
later exchanged genes before separating permanently.

From http://genepath.med.harvard.edu/~reich

[hunter]

23. Something else to think about...

Genus: Equus

E. asinus - Donkey
E. africanus - African Wild Ass
E. caballus - Domestic Horse
E. ferus - Wild Horse
E. grevyi - Grevy's Zebra
E. hemionus - Onager
E. kiang - Kiang
E. quagga - Plains Zebra
E. zebra - Mountain Zebra

It's a very similar and accepted structure to the proposed inclusion of Pan in the genus Homo

[Ediacara]

24. Most biologists already view Chimpanzees as members of Homo

Linnaeus even put chimpanzees in Homo when he created the genus.

[hunter]

25. It's obvious on the face of it, especially so with the genetics.

I think the comparison with Equus is a good one. The genetics of Equus speciation seem very similar to Homo, even taking into account domestication in the very latest stages. It can be said that in addition to domesticating horses and dogs, we domesticated ourselves.

As I dug deeper into this it struck me that the common ancestor of humans, bonobos, and chimpanzees was probably more bonobo-like. I'm going to draw my graph again with bonobo as the central line, since chimpanzees seem to have diverged from a bonobo-like plan more than humans.

Again, I don't think larger brains and bipedalism are all that distinguishing, and if you accept the final divergence of humans and chimpanzees was a little under 4 million years ago, then the 3 million plus year old Lucy is essentially a bipedal bonobo.

The nomenclature Australopithecus and Pan as separate genus apart from Homo has been poisonous to the way we think about human evolution, and most especially all the popular and absurdly linear presentations of human evolution.

It really wasn't all that long ago that we share common ancestors with chimpanzees and bonobos.

[semillama]

26. The problem with the Equus comparison

is that you can breed between the species in Equus and get viable offspring - not fertile offspring, but offspring none the less. To my knowledge, you can't do that with Pan and Homo, and it has been attempted.

Why shouldn't large brains and bipedalism be distinguishing enough? that's a pretty large difference in terms of how it affects behavior, range, ecological adaptation, and so on and so forth. That's enough right there to justify a separate genus. Actually, the fact we can be having this conversation on the internet is enough to warrant a separate genus, since the capability for abstract thought in our genus can be traced back to H. erectus. I can't stress enough that the establishment of a genus is based on more than just biology, a point that many posters here seem to gloss over.

It just seems like all your arguments come back to perceived slights and insults by Homo against Pan, and that's not a scientifically valid reason to switch the genus of a species.

[hunter]

27. To you it's obvious that Pan belongs in a separate genus.

If one looks only at the genes, it's obvious they don't.

Speciation seems to have occurred in cycles of diversification and hybridization to such an extent that incompatible X-chromosomes were pruned out of the common chimpanzee/human ancestor genome over the course of a few million years.

Our current cross species infertility seems to be the result of further chimpanzee adaptations to their forest environment, especially those related to tropical disease resistance. The human genome seems to have a remarkable tolerance for unusual chromosomal arrangements, so I'm guessing it was the modifications for tropical disease resistance that shut the door on cross-species fertility. This certainly saved us from various ethical quandaries given our demonstrated inability to deal with even trivial inherited traits such as skin color.

It now seems very likely that Homo erectus is a cousin species of ours and not a direct ancestor, in which case there isn't really anything we can trace back to them.

Here's a conservative human family tree at the Smithsonian Institute that illustrates this:

http://anthropology.si.edu/humanorigins/ha/a_tree.html

A lot of those dotted lines seem quite mad to me, and drawn for almost entirely political reasons. Quite naturally researchers want their own fossils to be direct human ancestors, and not some dead end.

Speculatively, I'd color most of the Smithsonian chart blue for genus Homo and guess the common ancestor of chimpanzees, bonobos, and humans to be something like Homo (Australopithecus) anamensis.

[semillama]

30. And once again, you ignore my point

Genus identification is NOT only about genes. If it were, we probably wouldn't be having this discussion.

You say it's obvious we don't belong in separate genus from the genes, but that's far from obvious. Homo and Pan gene flow ceased 4,000,000 years ago. (Homo-Pan-Gorilla speciation began about 6,000,000 years ago, btw, but curiously Gorilla is not included in your arguments for lumping Pan with Homo.) However, DIVERGENCE began occurring as long ago as 9,000,000 years ago. This is of course assuming the biochemical data is correct - there's some interesting theories out there that suggest it might not be, such as the appearance of a modern-looking ape at 22,600,000 years ago (Mororopithecus bishopi).

Genetic evidence needs to be considered, but so does morphology, behavior, ecological adaptation, and range. And when all that is considered, it points to separate genera for Pan and Homo. Perhaps future work will change that, and perhaps the whole Linnaean system will be discarded for a phylocladistic system. But now? I think that ultimately, more scientific research needs to be done before we go messing with genus status of species in Pan and Homo. It shouldn't be based on politics.

For example, there's a theory you'll find interesting addessing the divergence at 4-6mya of the African Great Ape lineages, which suggests that gorillas and chimpanzees evolved from australopithicines - chimps from the gracile forms, gorillas from the robust forms. If this were the case, then it would not only help explain the genetics, but also the lack of precursor fossils for the modern Pan Genus. Of course, then perhaps we'd have to become Australopithecus sapiens while chimps would be Australopithecus troglodytes.

And another side point to consider: Precedence in genus descrition. Pan was scientifically described as a genus before Homo, so if anything, according to your argument, we'd become Pan sapiens, or Pan vulgaris or whatever.

In the end, I think we probably both agree that chimpanzees and other great apes need to be protected, but where we disagree is the perceived effect that moving Pan troglodytes into genus Homo would have. I don't think that it would make any difference to people in the bush meat trade, for example.

[hunter]

33. I'd settle for Australopithecus vulgaris.

Let's get rid of Homo entirely.

In popular presentations of human evolution Homo is clearly little more than a name used to distance us from the other apes, no matter how the anthropologists might see it.

We're here in genus Homo and genus Pan is far away over there on that other branch. Sometime long ago God touched an Australopithecus and he became Homo. It wasn't bipedalism, it wasn't a big brain, so what was it? People start to think about souls and stuff... Nothing scientific about that, is there?

To a large extent Genus names have always been about politics and convention. Even species boundaries are subject to dispute.

My own academic background tends toward paleontology. I was highly influenced by Lynn Margulis, having attended a few of her lectures when genetic studies began to confirm her theories, and I still enjoy thinking about how the first eukaryotic cells might have come about. From my perspective everything from the Late Miocene onwards is recent history.

[hunter]

28. Equus Genetics -- Evolutionary movement of centromeres in horse, donkey, and zebra.

There's some wild stuff in here, and I imagine quite a bit of the same sort of thing has been going on within our own family tree:

Evolutionary movement of centromeres in horse, donkey, and zebra.

Lucia Carbonea, Solomon G. Nergadzeb, Elisa Magnanib, Doriana Misceoa, Maria Francesca Cardonea, Roberta Robertoa, Livia Bertonib, Carmen Attolinib, Maria Francesca Pirasb, Pieter de Jongc, Terje Raudseppd, Bhanu P. Chowdharyd, Gérard Guérine, Nicoletta Archidiaconoa, Mariano Rocchia, and Elena Giulotto

Abstract

Centromere repositioning (CR) is a recently discovered biological phenomenon consisting of the emergence of a new centromere along a chromosome and the inactivation of the old one. After a CR, the primary constriction and the centromeric function are localized in a new position while the order of physical markers on the chromosome remains unchanged. These events profoundly affect chromosomal architecture. Since horses, asses, and zebras, whose evolutionary divergence is relatively recent, show remarkable morphological similarity and capacity to interbreed despite their chromosomes differing considerably, we investigated the role of CR in the karyotype evolution of the genus Equus. Using appropriate panels of BAC clones in FISH experiments, we compared the centromere position and marker order arrangement among orthologous chromosomes of Burchelli's zebra (Equus burchelli), donkey (Equus asinus), and horse (Equus caballus). Surprisingly, at least eight CRs took place during the evolution of this genus. Even more surprisingly, five cases of CR have occurred in the donkey after its divergence from zebra, that is, in a very short evolutionary time (approximately 1 million years).These findings suggest that in some species the CR phenomenon could have played an important role in karyotype shaping, with potential consequences on population dynamics and speciation.

Excerpt from the paper:

Burchelli's zebra (Equus burchelli; EBU) and the donkey (Equus asinus; EAS) are two Equidae species that diverged about 0.9 million years ago (MYA), while their common ancestor diverged from the horse (Equus caballus; ECA) around 2 MYA. Donkey, Burchelli's zebra, and horse have 62, 44, and 64 chromosomes, respectively, and show a large number of chromosomal differences that have been pointed out using classical and fluorescence in situ hybridization (FISH) techniques. These data suggest that the karyotypes of these species are rapidly evolving. Spurred by the observation that, despite their greatly divergent karyotypes, horses, asses, and zebras show remarkable morphological similarity and capacity to interbreed, we investigated whether CR events were involved in the rapid chromosomal changes in the genus Equus. Toward this goal we performed FISH experiments on the chromosomes of these species to compare the marker order arrangement along orthologous chromosomes.

http://dx.doi.org/10.1016/j.ygeno.2005.11.012

I'm much enjoying this... I hadn't peeked in on human evolution for a couple of years now.

[cosmik debris]

29. The Human Genome project, The Hubble Telescope, and Bach's

Brandenburg Concertos are all products of a "vulgar" species?

I believe you are using selective observation to draw your conclusion.

Remember, in science, the theory must explain ALL of the evidence.

You can't reject evidence that does not fit your theory.

[hunter]

31. vulgar = common

Vulgar Latin for example was the Latin language as spoken by the common people, and it was quite fluid because it was unwritten. Before these Latin languages were written down and formalized there was no boundary between Italian, French, Spanish, etc.... regional variations flowed quite smoothly into one another.

My usage of Homo vulgaris simply means "the common people" and the class prejudice implied in that nomenclature amuses me. A million years from now our trash and our bones will be a very common sort of fossil, and if there are any intelligent creatures around our species will surely be viewed with some measure of contempt.

I'm not sure how to make this any clearer, but everything you mention, the art, the science, only have meaning to us. Celebrating it as something that distinguishes us from all other species is a kind narcissism.

"Oh look at us, we are so beautiful!"

So say the spoiled children of a cruel god.

Well, maybe not so beautiful. To any of the intelligent creatures we share the planet with human beings are an ugly and dangerous creature.

If cetaceans speak, if they have oral histories of human naval warfare, if they have witnessed all the bloody shattered bodies floating in the water, it's probably no surprise to them that they too are the object of our murderous ways.

Furthermore if our toolmaking monkey intelligence causes an ecological collapse that kills off this civilization and leaves us once again illiterate and smacking one another over the head with sticks, then we never were all that intelligent, were we?

I believe true intelligence still lies somewhere in the future. It may or may not be of the genus Homo. For all we know, the intellectual children of this civilization may be synthetic.

Our discomfort with our fellow hominids is very pronounced. They make us uncomfortable. I posted a picture of a bonobo earlier in this thread that photobucket saw fit to delete. It might have been for a copyright violation, but it's more likely Miss Bonobo looked a little too much like a frolicking nudist for someone's comfort. So here she is again wearing a matronly one piece swimsuit and some makeup:

[cosmik debris]

32. simply put

your version of taxonomy is an expression of your prejudice.

You can pretend that it is a linguistic issue, but it isn't.

You are willing to overlook any evidence that doesn't fit your theory. That makes your theory meaningless.

[hunter]

34. "Genus" is entirely a linguistic issue.

There is no biological reality to it. We can draw the lines of Genus anywhere we agree to, and we can modify the rules assigning a species to a Genus any way we agree to. Any biological theory based upon this arbitrary definition of "Genus" will be meaningless.

The entirely artificial and arbitrary genus classification Homo has been used to distance ourselves from the Genus Pan. It is often used as a very deliberate deception -- here we are on the branch Homo, and there far away is the chimpanzee, on the branch Pan.

No matter how uncomfortable it makes us, we are most closely related to the chimpanzees and bonobos. We are apes. By classifying the chimpanzees and bonobos as Homo we remove this self-deception.

A horse might look upon a zebra with some bewilderment, but both belong to the genus Equus.

[cosmik debris]

35. Well, you asked

"So, what do you think?"

I think you are expressing prejudice, not science,

[hunter]

36. Thanks for arguing!

That's what I wanted.

:hi: