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Originally posted by daniel58No, perhaps you ought to apologise before you witter any more, or had you forgotten?
Opposable thumbs, the ability to do complex math, the ability to create this computer we're typing on, the ability to create a language and refine it. Do I really need to keep going here?
Originally posted by daniel58Monkeys has four opposable thumbs. The majority of humans cannot do complex math. I haven't created a computer, nor has anyone I know, and before the first computer was invented humans were intelligent. Dr Zamenhof invented Esperanto, he was intelligent, what language did you invent? Animals has language for their need, even bees and ants has language. Yes, I think you need to keep going.
Opposable thumbs, the ability to do complex math, the ability to create this computer we're typing on, the ability to create a language and refine it. Do I really need to keep going here?
Originally posted by FabianFnasWhat does it mean to be human? For most people, it all comes down to that extraordinary object between our ears, and how it blesses us with language, laughter and logic. But not for Ajit Varki, a doctor-cum-scientist who works in California.
Monkeys has four opposable thumbs. The majority of humans cannot do complex math. I haven't created a computer, nor has anyone I know, and before the first computer was invented humans were intelligent. Dr Zamenhof invented Esperanto, he was intelligent, what language did you invent? Animals has language for their need, even bees and ants has language. Yes, I think you need to keep going.
For him, being human is also about a single chemical that separates us from our closest relatives, and which could be linked to many of our most debilitating illnesses.
The story began in 1984, when Prof Varki was working at the University of California, San Diego. When treating a woman with bone-marrow failure, he injected her with horse serum. The treatment carried the risk of a side effect called "serum sickness", in which the patient's immune system launches an attack on a molecule present in the serum called Neu5Gc.
Sure enough, her skin erupted with an itchy red rash. Investigating further, Prof Varki found that Neu5Gc was foreign to humans, even though we carry a very similar version of the same molecule - which may be one reason why animal-to-human organ and tissue transplants do not work well.
But in recent years, he has come to believe that the implications of this molecular difference are much wider. He has built up a range of evidence that potentially links Neu5Gc, a so-called sialic acid, to chronic disease.
This is because the animal version is absorbed by humans as a result of eating red meat and milk products, and there is evidence that the body views it as an invader.
Eating these foods could trigger inflammation and, over the long term, heart disease, certain cancers and auto-immune illnesses. Prof Varki stresses, however, that "we have not proven any link to disease, just suggested that it is something to explore".
This sialic acid plays a number of roles: it helps us recognise cells and helps cells stick together (this stickiness is also exploited by microbes, which latch on to the sugary molecule to invade our cells). It also helps regulate our immune response, which may influence the progression of diseases and even play a part in human evolution.
The first evidence that this particular molecule is of unique importance to humans came a decade ago. Prof Varki's team, along with Prof Elaine Muchmore, also of the University of California, studied blood from chimps, bonobos, gorillas, orangutans and humans.
They found that we are the only primates whose bodies do not produce Neu5Gc - although further research established that our Neanderthal cousins were missing this version of the sugar acid, too.
Instead, human (and Neanderthal) cells bristle with a sugar called Neu5Ac. The two molecules are identical, apart from one little detail: the ape molecule has a single extra oxygen atom. Because of the many different jobs this sugar does throughout the body, this one atom was the first example found of a fundamental genetic and biochemical difference between humans and our closest relatives.
Profs Muchmore and Varki then found out why this oxygen atom is missing: our molecule is the precursor of the animal version. Unlike chimpanzees and other great apes, humans lack a particular version of an enzyme that converts Neu5Ac (or, to give it its full name, N-acetylneuraminic acid) into Neu5Gc. This tiny change could potentially explain some of the more unusual differences between humans and apes.
Chimpanzees do not seem to suffer from heart disease, cancers, rheumatoid arthritis or bronchial asthma - common conditions in humans. Nor do they get sick from the human malaria parasite, which uses sialic acid to latch on to our blood cells.
In recent studies, Prof Varki's team has found tantalising evidence that this mysterious molecule could be exerting a wider effect on our health, through the substances we eat.
After testing a range of foods, they found the highest levels of Neu5Gc in red meat: up to 11,600 micrograms could be absorbed from the recommended daily serving of beef, 5,100 from pork and 4,900 from lamb. The level in goat's cheese was 5,500, but fell to around 700 in milk and salmon. Cod, tuna, turkey and duck were in the twenties.
Given that food is broken down in the stomach, did eating animal tissue present the same dangers of provoking an immune attack as transplanting it? Following that great scientific tradition of self-experimentation, Profs Varki, Muchmore and Pascal Gagneux ate pure Neu5Gc to see what would happen.
Not only did the foreign sugar show up in the body soon after eating, but tests also revealed that many people carry antibodies that react to Neu5Gc - a protective immune response, but one which could trigger damaging inflammation.
Prof Varki's colleague - and wife - Prof Nissi Varki then found that small amounts of Neu5Gc were present in normal human tissue, probably as a result of long-term consumption. And as well as food, many biotherapeutic products made in animal cells and/or using animal materials were also contaminated with Neu5Gc.
This raised the fascinating possibility that anti-Neu5Gc antibodies are involved in auto-immunity. Auto-immune diseases, such as type-1 or juvenile diabetes and some types of arthritis, occur when the body mistakenly attacks healthy tissue.
Because the animal version of the sugar is so similar to the human one, the latter could be caught in the friendly fire directed by the immune system. Chronic inflammation is also linked with cancer; intriguingly, the team found that Neu5Gc was concentrated in tumours, particularly those that spread throughout the body. This could aid detection of such diseases, by getting scientists to look for the animal acid rather than the tumours themselves.
Some of this might sound familiar: several previous studies have linked ingestion of red meat to cancer and heart disease, and possibly to some other disorders involving inflammation, such as arthritis and lupus. But these focused mostly on the role of saturated fats, and on products that arise from cooking.
Prof Varki, however, believes that his little molecular difference could also be to blame: Neu5Gc elicits an immune reaction that might contribute to a whole spectrum of human-specific diseases. Although they have not proven this yet, the evidence is sufficiently compelling for his team to start work on ways to eliminate Neu5Gc from the body.
But the question remains: why are humans unique among primates in not producing Neu5Gc?
By studying the mutations in the enzyme that makes this molecular difference between apes and humans, Prof Varki, along with Prof Naoyuki Takahata of the Graduate University for Advanced Studies in Kanagawa, Japan, estimates that the genetic change first appeared up to three million years ago, which coincides with the emergence of Homo erectus, the first of our ancestors to venture out of Africa.
At the time, life was nasty, brutish and short: any subtle but chronic effects of this foreign sugar would not be felt until old age, and Homo erectus did not survive that long.
If the mutation that kept us producing Neu5Ac rather than Neu5Gc helped shrug off a particular disease, it would have spread rapidly through the population. It is ironic that what may have protected our ancestors then could be responsible for much of the pain of their long-lived descendants.
Originally posted by daniel58You seem to have missed the point here. The OP asked whether humans are animals, we're not debating what makes us human.
What does it mean to be human? For most people, it all comes down to that extraordinary object between our ears, and how it blesses us with language, laughter and logic. But not for Ajit Varki, a doctor-cum-scientist who works in California.
For him, being human is also about a single chemical that separates us from our closest relatives, and which coul ...[text shortened]... cestors then could be responsible for much of the pain of their long-lived descendants.
Originally posted by daniel58I think you got a little off topic here.
What does it mean to be human? For most people, it all comes down to that extraordinary object between our ears, and how it blesses us with language, laughter and logic. But not for Ajit Varki, a doctor-cum-scientist who works in California.
For him, being human is also about a single chemical that separates us from our closest relatives, and which coul ...[text shortened]... cestors then could be responsible for much of the pain of their long-lived descendants.
You gave an example of a human quality: "Opposable thumbs."
Monkeys has four opposable thumbs. Does that mean the monkeys are more human than humans themselves in your opinion, or didn't you just thought of that?
(Before you get off topic again: Read this posting again and just answer my question. My posting is abut thumbs and nothing but thumbs.)
Originally posted by daniel58This passage is well beyond your abilities to compile. You have obviously copied it verbatim from somewhere. As I have said to you before, try thinking for yourself. People will have more respect for your posts.
What does it mean to be human? For most people, it all comes down to that extraordinary object between our ears, and how it blesses us with language, laughter and logic. But not for Ajit Varki, a doctor-cum-scientist who works in California.
For him, being human is also about a single chemical that separates us from our closest relatives, and which coul ...[text shortened]... cestors then could be responsible for much of the pain of their long-lived descendants.
Originally posted by JigtieYou can say birds fly, which does not make a bat a bird or a penguin
I'm not sure I follow. Are you saying that humans unlike animals are not controlled by instinct and
desires? Whether or not that's true, the fact remains that the definition of an animal is a body
physically separated from its environment, with the ability to move voluntarily. Humans are and
can do that, hence we're animals.
a giraffe, I’d say your definition is charitably vague to prove your
point.
Kelly
Originally posted by KellyJayThe bible says bats are birds (*). Modern biology does not. The bible is not a book of biology, nor evolution.
You can say birds fly, which does not make a bat a bird or a penguin
a giraffe, I’d say your definition is charitably vague to prove your
point.
Kelly
If you know anything about evolution you know that bats are not birds.
What's your point with this?
(*) Leviticus chapter 11, verse 13-19 says "And these are they which ye shall have in abomination among the fowls; they shall not be eaten, they are an abomination: the eagle, and the ossifrage, (bla, bla, bla) And the stork, the heron after her kind, and the lapwing, and the bat."
Originally posted by FabianFnasNo that makes them less human, because the only thing you can compare humans to are other humans, and no I didn't get off the point, if you read it again you will see that there is no possible way that we were anything but human.
I think you got a little off topic here.
You gave an example of a human quality: "Opposable thumbs."
Monkeys has four opposable thumbs. Does that mean the monkeys are more human than humans themselves in your opinion, or didn't you just thought of that?
(Before you get off topic again: Read this posting again and just answer my question. My posting is abut thumbs and nothing but thumbs.)
Originally posted by daniel58So you define humans as humans. That's circular, but fine for me.
No that makes them less human, because the only thing you can compare humans to are other humans, and no I didn't get off the point, if you read it again you will see that there is no possible way that we were anything but human.
I suppose you define animals as animals too...?
I, on the other hand, first define animals and see if humans fit into the definition. And, surprise surprise, humans do.
If primates evolved one specie to humans because of it's two thumbs, then I merely think that humans were devolved rather than evolved. How many times wouldn't you like to have two more hands (as monkies have) in order to do some complicated task?
Originally posted by FabianFnasDoesn't matter, when you can get a monkey to talk get back to me.
So you define humans as humans. That's circular, but fine for me.
I suppose you define animals as animals too...?
I, on the other hand, first define animals and see if humans fit into the definition. And, surprise surprise, humans do.
If primates evolved one specie to humans because of it's two thumbs, then I merely think that humans were devolved ...[text shortened]... ldn't you like to have two more hands (as monkies have) in order to do some complicated task?