Slashdot Mirror
Chimps Belong in Human Genus?
Bradley Chapman writes "I found this interesting story from Discovery News about our ties with chimpanzees. Excerpts: 'Chimpanzees share 99.4 percent of functionally important DNA with humans and belong in our genus, Homo, according to a recent genetic study.
Scientists analyzed 97 human genes, along with comparable sequences from chimps, gorillas, orangutans and Old World monkeys (a group that includes baboons and macaques). The researchers then took the DNA data and estimated genetic evolution over time. They determined that humans and chimps shared a common ancestor between 4 and 7 million years ago. That ancestor diverged from gorillas 6 to 7 million years ago.'" Genus is the next step up from species, if you recall your taxonomy. Humans are the only living species in genus homo, currently.
People don't seem to realize that we didn't actually evolve from chimps, but we actually are related in the way that we split off in the evolutionary timeline from the same predecessor. Why not put them in the same Genus as us? They've had just as much time to evolve.
For what it is worth, the raw similarity in the genome sequence doesn't need to indicate the same degree of similarity. Transcription is quite complex (much of it we still don't understand) and it is possible that small differences in regulatory regions can cause completely different parts of the sequence to be expressed.
A little of topic but a few days ago the result of Italian research project was published. The result of DNA comparisons between Neanderthals and Humans found that most likely no interbreeding have occured.
Help fight continental drift.
Original Submitter:
"Chimpanzees [...] belong in our genus, Homo"
Editor:
"Humans are the only living species in genus homo, currently."
Insert lamentation on the quality of Slashdot editorial review here.
We're turning over lots of taxonomies based on some cladistics-minded genetics lately. National Geographic threw in a chart and a couple of pages about re-grouping mammals a while back.
The chimps percentage might be a bit higher than we usually hear, but that number's basically been around. (Question is, how could our definition of a genus be this open to debate?)
"Fundamentalism" isn't about divine morality. It's about human authority.
Kings Play Chess On Funny Glass Stairs.
(Kingdom, Phylum, Class, Order, Family, Genus, Species)
That's the only damn thing I can remember from high school biology.
Bonus mnemonic -- the only thing I remember from high school history: "Divorced, Beheaded, She Died; Divorced, Beheaded, Survived." (How King Henry VIII's wives ended up)
Google for phylogeny, or just check out this page for a relatively good introduction. Comparative geneticists use sequence comparisons between species to determine relative evolutionary separation, much like the subject of the article. We haven't gotten rid of the kingdom-phylum-order-class-family-genus-species thing yet, but we're working on it.
Great spirits have always encountered violent opposition from mediocre minds. Albert Einstein
"The human genome is estimated to have as few as 30-45,000 functional genes" - Imperial College London (http://www.ic.ac.uk/P3509.htm)
Where did you get your "couple quadzillion" number from?
If you read this, you'll see that the analysis is based on 97 'critical' genes where a difference in a single base will produce a change in the amino acid coded for, and hence a change in the protein.
If the 'junk' DNA is included, there is more likelihood of variation between humans and chimps, but there is a corresponding rise in the variability within the human population which tends to lessen the overall significance of the inter-species variation.
Other than the fact that evolution would tend to favour the stability of these 97 'critical' genes, I see no problem with this analysis, but think that putting humans and chimps in the same genus is pushing matters slightly.
oh brave new world, that has such people in it!
Wolves are not genetically identical to dogs, any more than beagles are genetically identical to rotweilers: the consistent phenotypic differences between dog breeds, and between dogs and wolves, are genetically determined.
If being genetically identical were the key, each human (or pair of twins) would be a species unto himself.
But what people mean by species is usually more determined by whether the animals interbreed and produce fertile offspring (this gets fuzzy with plants and is more or less irrelevant to bacteria, but still...).
Dogs and wolves are close enough to interbreed, successfully and often, and a lot of people would class dogs as a subspecies of wolf (Canis lupus latrans).
But classification by genus and higher levels is fairly arbitrary, based mostly on what people see as significant differences and similarities (e.g. people are different from apes, cats all kind of look alike). The only important thing is that the basic nesting is right, so that if species A and B have a common ancestor, and C and D are descended from B, then if A and C are in one class, B and D are also in that class.
It might be more rational to have a system that took each branching into account, but we don't have enough information for that, and it would be inconvenient to deal with.
To sum up: the argument that no one calls a wolf a dog is incorrect, but there's still no point in calling a chimp a Homo.
So far
total human reads: 23 million
total chimp reads (Pan troglodytes): over 12 million
having worked on annotation of a few of the chimp BAC clones, I can assure you the two species range from about 97% to over 99.9% similar at the DNA sequence level.
You bet that we may see differences? So what you are saying is that dispite the fact that you nor anyone else has any evidance one way or another to believe that there will be more 'diff' found in the future you still feel you should express you oppinion about it. You seem to really only be expressing what out come you dessire. Not what out come is likely.
Sex is what happens when people think no one else will ever find out
Link
Ok you're right, its probably not 98%. But this article is very informative about the matter. For the most part we share at least 25% with all living things and its probably significiently higher.
Insightful part:
Once again, the DNA comparison requires context to be meaningful. Granted that a human and ape are over 98% genetically identical, a human and any earthly DNA-based life form must be at least 25% identical. A human and a daffodil share common ancestry and their DNA is thus obliged to match more than 25% of the time. For the sake of argument let's say 33%.
The point is that to say we are one-third daffodils because our DNA matches that of a daffodil 33% of the time, is not profound, it's ridiculous. There is hardly any biological comparison you can make which will find us to be one-third daffodil, except perhaps the DNA.
I think thats an excellent point.
can't sleep slashdot will eat me
Our current system for categorizing the inhabitants of this is long outdated and is based largely on phsycal characteristics of the components on the creature, rather than the stuff it is actually made up of.
We find we've had to tweak this existing system to make new species fit
I agree completely. In fact even the concept of species is not so well-defined any more, because there are examples of groups of animals where group A can mate with group B and group C, but groups B and C cannot mate with each other. Are they different species or the same?
A better, more accurate, system needs to be devised based on current technologies that classify based on genetic code. The point of a classification system would be to allow us to draw similarities in creatures while studying them based on available data for ones in the same category. A genetic model would be very beneficial for this very reason.
The answer to your question is called cladestics, where species are classifed not based on observed similarities, but rather based on common heritage.
Common heritage can be established either from genetics or from counting the number of significant traits that differ or are the same, and using sophisticated computer programs to calculate probable common starting points.
A few provocative results are that birds are dinosaurs (dinosaurs are defined by a common ancestor, and since birds come from dinosaurs that make them dinosaurs too). Furthermore dinosaurs (including birds) are reptilians.
Tor
Umm not quite. Dogs have been selectively bred a lot longer than 5k years first. Second breeding Timberwolves and Huskies, while possible, positively requires human intervention. It could never happen in the wild, first because the wolf would more likely kill the dog than mate with it, and secondly because wolves and dogs have very different estrus cycles.
Wolves and dogs are thus clearly different species, just as asses and horses are. Remember, asses and horse *can* mate - but it's problematic and extremely unlikely without human intervention. To be the same species it needs to be possible to mate normally - not with great difficulty and lots of outside intervention.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Friends don't let friends enable ecmascript.
Recalling basic biology, species are capable of interbreeding (http://dictionary.reference.com/search?q=species) . A little chimp-changa won't produce much of anything (HIV?)
I appreciate it may not be a necessary feature of belonging to the same genus, but I also note that horses and donkeys are in the same genus at least partly because they are capable of producing infertile offspring (mules). Is the rest not simple binomial taxonomy? The apparent physical differences are minor, and the mental? A little readinng will show chimps have a sense of 'self' (will recognize their appearance has been changed in a mirror), knowledge of others beliefs (they engage in teaching), and even a capacity for commerce! (SCIAM had a wonderful anecdote about chimps that were given vending machine tokens, learned to stockpile, trade, and even counterfeit them!)
Umm no. If you put humans, bonobos, chimps, gorillas, orangs, and gibbons in one genus, you most assuredly have NOT included all primates or even close. The vast majority of primates are old world monkeys, new world monkeys, and lemurs. The word you were looking for here was apes, not primates.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Friends don't let friends enable ecmascript.