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Natural Science Forum / Biology / Biology / April 2004our and animals' hemoglobin
Hemoglobin transports oxygen. Our hemoglobin is similar to that of gorillas, chimpanzees, and monkeys. Not the same, but similar. Our hemoglobin is less similar to that of cows, horses, pigs, chickens, horses, whales, and rabbits. Our hemoglobin is even less similar to that of turtles, snakes, and lizards. There is no physiological reason for hemoglobin to be different in humans, chimpanzees, gorillas, and monkeys. There is no physiological reason for hemoglobin to be different in humans, cows, horses, pigs, chickens, horses, whales, and rabbits. There is no physiological reason for hemoglobin to be different in humans, turtles, snakes, and lizards. >There is no physiological reason for hemoglobin to be different in >humans, chimpanzees, gorillas, and monkeys. >There is no physiological reason for hemoglobin to be different in >humans, cows, horses, pigs, chickens, horses, whales, and rabbits. >There is no physiological reason for hemoglobin to be different in >humans, turtles, snakes, and lizards. Actually there is reason, whales are a good example. they need super effecient hemoglobin so they can hold their breath for a long time. Other animals have other needs, chimps actually have some of the same blood types as humans and could be used as blood doners but that would open us up to cross infection with viruses that chimps are immune to and we aren't, like aids. Moon >>There is no physiological reason for hemoglobin to be different in >>humans, chimpanzees, gorillas, and monkeys. [quoted text clipped - 10 lines] > >Moon David ford's post about hemoglobin doesn't seem to have any point. It is a mystery why he would announce such old and well-known facts. Is he simply trying to illustrate neutral variation -- genetic drift? Whale hemoglobin is not a super oxygen binder -- it still holds one molecule of oxygen per heme group, just like all the others. The slight differences in amino acid sequence do make some differences in how oxygen binds, in the affinity and in the sensitivity of hemoglobin to other factors like pH or DPG or other regulators. Still, probably much of the variation is neutral. Blood types and immune responses to transfusions are based on many factors, but hemoglobin is not one of them. >Whale hemoglobin is not a super oxygen binder -- it still holds one >molecule of oxygen per heme group, just like all the others. I have seen it quoted in many forms of literature that hemoglobin in whales is much more effecient than in humans. I don't know in what way but i would have to do some reserch before i would dismiss an idea with so much backing. You may be right but like I said i've seen it written many times and quoted in lecutures on the subject. Moon >>Whale hemoglobin is not a super oxygen binder -- it still holds one >>molecule of oxygen per heme group, just like all the others. [quoted text clipped - 4 lines] > so much backing. You may be right but like I said i've seen it written > many times and quoted in lecutures on the subject. Whales can release more oxygen from their haemoglobin. Venous blood in humans, after releasing oxygen, is normally about 40% saturated, i.e., only 60% oxygen is released. In extreme hypoxia this can go up to about 65%. Whales can release 90% oxygen from their haemoglobin. It is not only haemoglobin, or more accurately the three dimentional structure of the globin chains that matters. As Norman has pointed out several other control mechanisms are involved in this better oxygen release phenomenon.  SignatureGautam Majumdar Please send e-mails to gmajumdar@freeuk.com >>>Whale hemoglobin is not a super oxygen binder -- it still holds one >>>molecule of oxygen per heme group, just like all the others. [quoted text clipped - 12 lines] >globin chains that matters. As Norman has pointed out several other control >mechanisms are involved in this better oxygen release phenomenon. I believe a major factor is in the quantity of myoglobin whales have in their tissues. Myoglobin is an efficient oxygen binding agent with much higher affinity than hemoglobin and is capable of removing oxygen from the blood for storage in the tissue. Still, the question remains unanswered: what in the world did David Ford have in mind by posting all that stuff? >Hemoglobin transports oxygen. > [quoted text clipped - 4 lines] >Our hemoglobin is even less similar to that of turtles, snakes, and >lizards. Yes. The degree of difference is correlated with phylogenetic distance, i.e. the more closely related two groups are, the more similar their hemoglobin is likely to be. Do you have some other point? >There is no physiological reason for hemoglobin to be different in >humans, chimpanzees, gorillas, and monkeys. You are aware that there are people with mutant forms of hemoglobin, right? Sometimes it's bad for them not to be more standard. And there's also fetal hemoglobin in mammals, convenient for those times before you start breathing. >There is no physiological reason for hemoglobin to be different in >humans, cows, horses, pigs, chickens, horses, whales, and rabbits. Dunno about that. Chickens can fly, after all, and whales can deep dive, remaining submerged for hours. >There is no physiological reason for hemoglobin to be different in >humans, turtles, snakes, and lizards. Dunno about that either. Turtles can hibernate submerged in the mud at the bottom of both fresh and salt waters for months on end. Reptiles in general have a much lower oxygen requirement and higher CO2 tolerance than mammals and birds because they don't maintain their body temperatures by producing heat by oxidizing foods. So their hemoglobin doesn't need to be as good as that of birds and mammals. Of course, there's a lot more to regulating oxygen levels than the characteristics of hemoglobin, and I don't know how important hemoglobin is vs other factors in giving different taxa their ability to manage their oxygen levels when they do remarkable things like fly or stop breathing for hours or months. So whatever your point is, "no physiological reason" for differences is incorrect. > Our hemoglobin is similar to that of gorillas, chimpanzees, and > monkeys. Not the same, but similar. [...] > There is no physiological reason for hemoglobin to be different in > humans, chimpanzees, gorillas, and monkeys. [...] People have already responded to this - so I won't go into it again. I just want to add that being different essentially means the sequence has changed over the course of evolution. This may or may not lead to *functional* differences. But my main question ist this: What point are you trying to make? Are you wondering why they have diverged? Do you think this fact supports/contradicts some theory (which?)? I think the discussion would get a lot more meaningfull if we knew your question/point/whatever. cu Philipp SignatureDr. Philipp Pagel Tel. +49-89-3187-3675 Institute for Bioinformatics / MIPS Fax. +49-89-3187-3585 GSF - German National Research Center for Environment and Health Email: p.pagel AT gsf . de http://mips.gsf.de/~pagel |
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