macleod@drivax.UUCP (MacLeod) (08/05/89)
David Casseres writes:
:: American Blacks
:: are highly hybridized with Whites, and exhibit the hybrid vigor
:: so prized by athletic teams.
:If some people posted this bullshit, I would assume they didn't know it
:was racist ignorance. In your case, I assume that you do know, and that
:either you are a racist or you are just being a self-indulgent wise guy.
I may well be wrong, so tell me where my analysis goes astray.
Back in high school biology, I was taught that a eugenics program should
take a given gene pool and inbreed it for 20 generations, weeding out
the recessive-gene problems dredged up by the increasingly homozygous
population. At this point, the gene pool is outbred to a very different
one, and the F1 generation produced exhibits heterozygous "hybrid vigor",
often exceeding either parent stock in desired traits.
European and African gene pools were at least 20 generations apart when
they were merged in America, and the hybridized slaves were pruned further
by clever owners, so it doesn't surprise me that professional sports is
dominated by black Americans and black-Native American-white hybrids.
(Native to South America, that is, where they interbred with the European
Spanish.)
Of course, we're all supposed to pretend that none of this ever happened...
Michael Sloan MacLeod (amdahl!drivax!macleod)ekwok@cadev4.intel.com (Edward C. Kwok) (08/08/89)
In article <4869@drivax.UUCP> macleod@drivax.UUCP (MacLeod) writes: >European and African gene pools were at least 20 generations apart when >they were merged in America, and the hybridized slaves were pruned further >by clever owners, so it doesn't surprise me that professional sports is >dominated by black Americans and black-Native American-white hybrids. >(Native to South America, that is, where they interbred with the European >Spanish.) > >Of course, we're all supposed to pretend that none of this ever happened... You are, of course, making the assumption that the genetic ability to produce the melanin pigment has anything to do with the rest of the genetic makeup of the individual; and that "black people" and "white people" are all alike. Well, the news is that if you take two "black" people from different parts of Africa, albeit 200 miles apart, they may be very different in every ability, except for the ability to produce the pigment in their skin. To talk about a result without knowing about the "starting" material is quite likely to form erroneous conclusions. Also, I will contest that athletic ability is not like the ability to produce a pigment. Such high level characteristics are probably not manifestation of just a few genes. They are probably a combinations of the effects of many genes, as well as of environmental influence. When you have so many factors operating all together, it's not at all clear that by concentrating the dominant forms of certain phenotypes, one can at the same time avoid concentrating the recessive forms of other phenotypes. (i.e. we don't know if and when we create the individual with potential to develop muscles to run a 9.0 sec 100 meters, we don't also have at the same time an individual who cannot survive the attack of a common cold). Besides, the "dominant/recessive" terminology inadvertently make people associate the ideas with good/bad. Natural does not make such associations. The same genetic "defect" that creates the "sickle cell" anaemia, is also the responsible for the survival in malaria swamps. The points I am trying to make: 1. If the ability to produce pigment is independent of the ability to excel in athletics (itself a grossly general term: is bowling an athletic endeavor?), one has no better luck creating a super-athelete imbreeding whites than imbreeding a mixture of "black" and "whites" and their offsprings. 2. Even if we assume that athletic ability is controlled by a few genes that can be "purified" from the original "black" and the original "white" genetic makeup, it is not clear that the successful manifestation of the atheletic ability may not be thwarted by the same process "purifying" some other genes unfavorable to the given environment. So that this "purifying" process may create no better athletes than the randomly occuring events that occur within "blacks", "whites", or "in betweens".
lsefton@Apple.COM (Laurie Sefton) (08/08/89)
In article <4869@drivax.UUCP> macleod@drivax.UUCP (MacLeod) writes: > >David Casseres writes: > >:: American Blacks >:: are highly hybridized with Whites, and exhibit the hybrid vigor >:: so prized by athletic teams. > >:If some people posted this bullshit, I would assume they didn't know it >:was racist ignorance. In your case, I assume that you do know, and that >:either you are a racist or you are just being a self-indulgent wise guy. > >I may well be wrong, so tell me where my analysis goes astray. > >Back in high school biology, I was taught that a eugenics program should >take a given gene pool and inbreed it for 20 generations, weeding out >the recessive-gene problems dredged up by the increasingly homozygous >population. At this point, the gene pool is outbred to a very different >one, and the F1 generation produced exhibits heterozygous "hybrid vigor", >often exceeding either parent stock in desired traits. > >European and African gene pools were at least 20 generations apart when >they were merged in America, and the hybridized slaves were pruned further >by clever owners, so it doesn't surprise me that professional sports is >dominated by black Americans and black-Native American-white hybrids. >(Native to South America, that is, where they interbred with the European >Spanish.) > >Of course, we're all supposed to pretend that none of this ever happened... > > >Michael Sloan MacLeod (amdahl!drivax!macleod) Okay--we're talking the difference between a small group of highly inbred animals (think thoroughbreds, Ancon sheep, Irish Dexter Cattle), versus a fairly genertically disparate group of people. Take a look at sub-saharan Africa--that's a pretty large place. You may find a few genetic areas in common, but you can say the same for Mediterraneans, and incidence of Cooley's anemia. Do you expect the same homozygocity between Spaniards and Greeks as you do Masaai and Yoruba? Laurie Sefton
casseres@apple.com (David Casseres) (08/09/89)
In article <4869@drivax.UUCP> macleod@drivax.UUCP (MacLeod) writes: > David Casseres writes: > > :: American Blacks > :: are highly hybridized with Whites, and exhibit the hybrid vigor > :: so prized by athletic teams. > > :If some people posted this bullshit, I would assume they didn't know it > :was racist ignorance. In your case, I assume that you do know, and that > :either you are a racist or you are just being a self-indulgent wise guy. > > I may well be wrong, so tell me where my analysis goes astray. > > Back in high school biology, I was taught that a eugenics program should > take a given gene pool and inbreed it for 20 generations, weeding out > the recessive-gene problems dredged up by the increasingly homozygous > population. At this point, the gene pool is outbred to a very different > one, and the F1 generation produced exhibits heterozygous "hybrid vigor", > often exceeding either parent stock in desired traits. I have only heard of "hybrid vigor" in the context of agricultural crops. I have never heard of it being applied to human populations. > > European and African gene pools were at least 20 generations apart when > they were merged in America, and the hybridized slaves were pruned further > by clever owners, so it doesn't surprise me that professional sports is > dominated by black Americans and black-Native American-white hybrids. > (Native to South America, that is, where they interbred with the European > Spanish.) But neither the European nor the African gene pools were inbred. "Hybrid vigor" is about reversing the disadvantages of a small, inbred gene pool. Professional sports has a lot of non-white players because it is one of the few really good economic niches open to them. But compared to the other niches available to whites, it isn't so hot; therefore there are not as many whites in pro sports as there might be. By the way, a very large sector of the "white" American population is just as mixed as the "black" population. I've seen estimates that as many as 25% of white Southerners have some African ancestry. David Casseres Exclaimer: Hey!
timlee@ernie.Berkeley.EDU (08/09/89)
In article <3411@internal.Apple.COM> casseres@apple.com (David Casseres) writes: |By the way, a very large sector of the "white" American population is just |as mixed as the "black" population. I've seen estimates that as many as |25% of white Southerners have some African ancestry. Also Native American ancestry.
jk3k+@andrew.cmu.edu (Joe Keane) (08/09/89)
casseres@apple.com (David Casseres) writes: >"Hybrid vigor" is about reversing the disadvantages of a small, inbred gene >pool. Says who? People have been breeding things for a long time. Plants, animals, maybe even humans. Breeding involves finding different varieties of a species, and arranging to have the best traits from each. This is indeed what `hybrid vigor' refers to. Certainly it can be used to reverse inbreeding, but this isn't a necessary condition.
arrom@aplcen.apl.jhu.edu (Ken Arromdee) (08/09/89)
>By the way, a very large sector of the "white" American population is just >as mixed as the "black" population. I've seen estimates that as many as >25% of white Southerners have some African ancestry. Of course, everyone has African ancestry... -- "The fact is self evident from the text and requires no supporting argument." --Tim Maroney Kenneth Arromdee (UUCP: ....!jhunix!ins_akaa; BITNET: g49i0188@jhuvm; INTERNET: arromdee@crabcake.cs.jhu.edu) (please, no mail to arrom@aplcen)
jackson@ttidca.TTI.COM (Dick Jackson) (08/09/89)
In article <3411@internal.Apple.COM> casseres@apple.com (David Casseres) writes: > >Professional sports has a lot of non-white players because it is one of >the few really good economic niches open to them. But compared to the >other niches available to whites, it isn't so hot; therefore there are not >as many whites in pro sports as there might be. > We're getting into politically dangerous ground here, do I detect a hidden agenda? I hope not. But I will boldy (foolhardily?) introduce another point, namely that in track, blacks dominate the sprints, whites dominate the long distances and there is rough equality around 800 meters. I can think of no socio-economic argument to explain this. Dick Jackson
neal@lynx.uucp (Neal Woodall) (08/10/89)
MacLeod writes: American Blacks are highly hybridized with Whites, and exhibit the hybrid vigor so prized by athletic teams. Casseres writes: If some people posted this bullshit, I would assume they didn't know it was racist ignorance. In your case, I assume that you do know, and that either you are a racist or you are just being a self-indulgent wise guy. MacLeod writes: Back in high school biology, I was taught that a eugenics program should take a given gene pool and inbreed it for 20 generations, weeding out the recessive-gene problems dredged up by the increasingly homozygous population. At this point, the gene pool is outbred to a very different one, and the F1 generation produced exhibits heterozygous "hybrid vigor", often exceeding either parent stock in desired traits. Casseres writes: I have only heard of "hybrid vigor" in the context of agricultural crops. I have never heard of it being applied to human populations. Mr. Casseres is clearly ignorant on this: hybrid vigor can indeed be applied to things other than agricultrual crops.....it is also frequently applied to agrcultural stock (ie, animals) as well. Perhaps the reason you hardly ever hear of it being aplied to humans is because it invariably causes a furior among the "progressives" who fear that it could be used to further racial discrimination. In fact, Mr. Casseres himself demonstrates this in his quote above. It is because of the inevitable cries of "racism" and "discrimination" from the so-called "progressives" that this subject cannot usually be discussed in a rational fashion. I have my own views on this, and at the risk of being flamed or worse, I am going to enter this fray. It is my understanding that the journey to the North American continent was very hard for the slaves that were brought from Africa....hundreds of slaves crowded into the cargo holds of ships, given little food and water. The heat from the crowded bodies alone was enough to kill about 20% of them. Sometimes the attrition rates for the entire trip would be almost 50% of an original group of captured Africans. Is it any suprise that the ones who eventually made it to America were of superior physical constitution and genotype? When the slaves arrived in this country, they were sold to the plantation owners for the purposes of physical labor....the owners did not want small and weak slaves, they wanted strong slaves that could toil for hours a day in the fields. They undertook breeding programs to produce the strongest slaves with superior stamina....they bred the largest, strongest slaves to all of the slave women in order to have succeding generations of strong and hard working slaves. Also, it was not uncommon for the sons of the plantation owners to take a concubine negro woman to learn sex from. The children of these women carried the genes of both the African women and the Anglo men, resulting in the mixing of the gene pools that McLeod wrote about that could indeed have resulted in "hybrid vigor". Is it any suprise that Afro-Americans excell at most sports (ie, are represented in most sports in numbers that are vastly larger than their representation in the general population would suggest)? They have superior genes (in general) for physical strength and stamina. I hope that people can examine these ideas OBJECTIVELY, without putting too much emotional content into them. These statements are NOT ment to be racist in nature, and I hope that people will discuss this in a rational way, rather than flaming me or calling me names. Neal
mike@uxf.cso.uiuc.edu (Mike Trogni) (08/10/89)
A previous poster was correct in reminding us that every human being that has ever been born has African roots (as scientific study of human ancestry suggests). Most evolutionary textbooks today use the term "race" *very* loosely in regard to the human species. Most scientists would rather say that there is one race, the human race. Always be very careful when reading studies involving classification of human beings. _The Mismeasure of Man_ by Stephen Jay Gould of Harvard U. is recommended to everyone - from the layman to the graduate student in biology. Racist claims in human genetics usually evolve from hidden agendas or unintended experimental bias. I would say that the relative preponderance of people of African ancestry in certain atheletic endeavors *can not* be ascribed to one reason, but to a variety of inherited *and* environmental factors. Hybrid vigor is something I would use to describe the strength of a plant species, not something I would use to talk about the success of another human being. -mike [mike@uxf.cso.uiuc.edu]
mkkuhner@codon1.berkeley.edu (Mary K. Kuhner;335 Mulford) (08/10/89)
Hybrid vigor is well known in plants and animals--when two inbred stocks are crossed, the offspring are often more vigorous because (a) they are not homozygous for as many deleterious recessives, and (b) they are possibly heterozygous for genes where the heterozygote is the most vigorous type. Human races are not inbred. The difference between an 'average' Caucasian and an 'average' Negro is less than the difference between individuals of each race. There is no obvious reason why racial hybrids would show hybrid vigor. Selection for vigor in African-Americans is another matter which has nothing to do with 'hybrid vigor' as plant or animal breeders understand it. I am not sure how this hypothesis could practicably be tested, but there's nothing wrong with trying to think of a way to do it. Why the yells of 'racist'? Human races may not be as differentiated as has been thought, but surely the way to prove this is to study them, not to push the whole topic under the rug. Some geneticists may find it useful to group all humans together without regard to race, but in the population genetics of disease it is vital to match the control and disease populations by race. The occurence of juvenile diabetes in American-Americans, for example, correlates quite exactly with the proportion of Caucasian admixture, and Africans almost never get this disease. Mary Kuhner mkkuhner@enzyme.berkeley.edu
mkkuhner@codon1.berkeley.edu (Mary K. Kuhner;335 Mulford) (08/10/89)
Hybrid vigor is well known in plants and animals--when two inbred stocks are crossed, the offspring are often more vigorous because (a) they are not homozygous for as many deleterious recessives, and (b) they are possibly heterozygous for genes where the heterozygote is the most vigorous type. Human races are not inbred. The difference between an 'average' Caucasian and an 'average' Negro is less than the difference between individuals of each race. There is no obvious reason why racial hybrids would show hybrid vigor. Selection for vigor in African-Americans is another matter which has nothing to do with 'hybrid vigor' as plant or animal breeders understand it. I am not sure how this hypothesis could practicably be tested, but there's nothing wrong with trying to think of a way to do it. Why the yells of 'racist'? Human races may not be as differentiated as has been thought, but surely the way to prove this is to study them, not to push the whole topic under the rug. Some geneticists may find it useful to group all humans together without regard to race, but in the population genetics of disease it is vital to match the control and disease populations by race. The occurence of juvenile diabetes in African-Americans, for example, correlates quite exactly with the proportion of Caucasian admixture, and Africans almost never get this disease. Mary Kuhner mkkuhner@enzyme.berkeley.edu
logajan@ns.network.com (John Logajan) (08/10/89)
In article <5983@lynx.UUCP>, neal@lynx.uucp (Neal Woodall) writes: > Is it any suprise that Afro-Americans excell at most sports (ie, are > represented in most sports in numbers that are vastly larger than their > representation in the general population would suggest)? They have > superior genes (in general) for physical strength and stamina. I don't see this as a meaningful comparison -- apples to oranges, and all that. You would have to compare the physical attributes of american blacks with their "old" country (African continent) relative. Also, no fair comparing geographically inappropriate groups. -- - John M. Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428 - - logajan@ns.network.com / ...rutgers!umn-cs!ns!logajan / john@logajan.mn.org -
casseres@apple.com (David Casseres) (08/10/89)
In article <5983@lynx.UUCP> neal@lynx.uucp (Neal Woodall) writes: > Mr. Casseres is clearly ignorant on this: hybrid vigor can indeed be applied > to things other than agricultrual crops.....it is also frequently applied to > agrcultural stock (ie, animals) as well. Perhaps the reason you hardly ever > hear of it being aplied to humans is because it invariably causes a furior > among the "progressives" who fear that it could be used to further racial > discrimination. In fact, Mr. Casseres himself demonstrates this in his quote > above. It is because of the inevitable cries of "racism" and "discrimination" > from the so-called "progressives" that this subject cannot usually be > discussed in a rational fashion. Well, EXCUSE ME for saying something is racist. I guess nobody should ever call anything racist again, ever (except affirmative action), for fear of making non-progressives afraid to talk. Give me a break, Neal. > I have my own views on this, and at the risk of being flamed or worse, I am > going to enter this fray. Well, let's give you a great big medal for your astonishing bravery!!! [lengthy argument about genetic history of American blacks, omitted for brevity] > I hope that people can examine these ideas OBJECTIVELY, without putting too > much emotional content into them. These statements are NOT ment to be > racist in nature, and I hope that people will discuss this in a rational > way, rather than flaming me or calling me names. Guess what, Neal? I don't think your argument is racist, and so I'm not going to call you a racist. You can come out from under the bed. However, I did think that MacLeod's statement was racist. You figure it out. David Casseres Exclaimer: Hey!
casseres@apple.com (David Casseres) (08/10/89)
In article <5264@ttidca.TTI.COM> jackson@ttidca.TTI.COM (Dick Jackson) writes: > In article <3411@internal.Apple.COM> casseres@apple.com (David Casseres) writes: > > > >Professional sports has a lot of non-white players because it is one of > >the few really good economic niches open to them. But compared to the > >other niches available to whites, it isn't so hot; therefore there are not > >as many whites in pro sports as there might be. > We're getting into politically dangerous ground here... I don't think it's "politically dangerous." Why do you? > ...do I detect a hidden agenda? I hope not. No. Don't be such a jerk. If you think I have some sinister, covert purpose, say what it is. > But I will boldy (foolhardily?) And another valiant hero steps forward!! Stamp out another medal for this dude! > introduce another point, > namely that in track, blacks dominate the sprints, whites dominate the long > distances and there is rough equality around 800 meters. I can think of no > socio-economic argument to explain this. Neither can I. Maybe it's because of a physical difference. Did you have a point to make? David Casseres Exclaimer: Hey!
barkley@unc.cs.unc.edu (Matthew Barkley) (08/10/89)
In article <1989Aug10.003610.14496@agate.berkeley.edu>, mkkuhner@codon1.berkeley.edu (Mary K. Kuhner;335 Mulford) writes: > > Some geneticists may find it useful to group all humans together > without regard to race, but in the population genetics of disease > it is vital to match the control and disease populations by race. > The occurence of juvenile diabetes in African-Americans, for example, > correlates quite exactly with the proportion of Caucasian admixture, > and Africans almost never get this disease. > "Race" may be a handy label, even in population genetics, but it really has no scientific validity, IMHO. How does one tell the "proportion of Caucasian admixture"? Remember that Asian Indians are considered Cau- casian; is that part of the admixture, too? What objective criteria do you have for classification? To put the whole thing into sharp focus: The singer Don Ho is said to be of Portugese, Chinese, and Hawaiian ancestry; what "race" is he? Matt Barkley barkley@cs.unc.edu Any opinions expressed are not necessarily shared by anyone else, and may not even be my own. How an organization can have an opinion is beyond me.
moon@oliveb.OLIVETTI.COM (Gordon Moon,Parking Lot,911,7671234) (08/11/89)
From article <5264@ttidca.TTI.COM>, by jackson@ttidca.TTI.COM (Dick Jackson): > We're getting into politically dangerous ground here, do I detect a hidden > agenda? I hope not. But I will boldy (foolhardily?) introduce another point, > namely that in track, blacks dominate the sprints, whites dominate the long > distances and there is rough equality around 800 meters. I can think of no > socio-economic argument to explain this. Sorry but whites do not dominate the long distances in track and field. That is unless you think that the superb athletes from Kenya are white.
pell@boulder.Colorado.EDU (Anthony Pelletier) (08/11/89)
> neal@lynx.uucp (Neal Woodall) writes: >> Mr. Casseres is clearly ignorant on this: hybrid vigor can indeed be >applied >> to things other than agricultrual crops.....it is also frequently >applied to >> agrcultural stock (ie, animals) as well. Perhaps the reason you hardly >ever >> hear of it being aplied to humans is because it invariably causes a >furior (David Casseres) writes: >Well, EXCUSE ME for saying something is racist. I guess nobody should >ever call anything racist again, ever (except affirmative action), for >fear of making non-progressives afraid to talk. Give me a break, Neal. > Good response dave...if you can't address the point (that you were incorrect in your claims about hybrid vigor) slander the other guy and drag in emotional issues. I should add that I don't think Hybrid vigor is the reason for the phenominon we are discussing since it really only applies to the "F1" generation. For each ensuing generation the chance of being homozygoes for a deliterious allele starts to go up again. I think the first point to make is that there are differences--average height, bone density etc.--between races. One poster has pointed out that the difference among people of a given race can be more than that between races. That is certainly true. The bell curves certainly intersect over most of their volume--but we are not talking about the average here. We are talking about world class atheletes; I expect them to be several standard deviations off the mean for many things. Statistics will tell you that for two normal curves displaced even by a small amount, the points at the leading edge of one will be farther out than those of the the other. Or, for a given point on the X-axis, there will be more representitives in one group than the other. Take for example the question raised by one poster of why long distance runners are predominantly white and sprinters are predominantly black (kenyan's notwithstanding). You might also notice that there are distict differences in body type between the two groups of atheletes--the sports put different demands on the atheletes. Why is it racist to suggest that one body type is found more often in one race than the other? The basis of the expression of genetic differences is simple biochemistry. There is no racism invoved to say, for example, that scicle-cell anemia exists only in people of African desent. A particular variant of hemoglobin that is found (so far) only in blacks is the cause. But other traits about which we are speaking can be described as simple biochemical differences (arising from genetic differences). The action of muscle is pure biochemistry. I won't go into details of the contraction cycle. But, suffice it to say that each myosin head must cycle many times to move a muscle at all. The rate at which each myosin head can be re-set and therefore re-cycle sets a built-in limit on contraction velocity. Things that make the cycle go more quickly would tend to make the velocity of contraction greater. Consider a hypothetical example: If there were two common variants of Myosin Light-chain Kinase, one with a high Vmax and high Km(ATP), the other with the oposite profile, people with the former could contract the muscle with greater velocity, exerting greater thrust, but would fall below optimal ATP concentrations very rapidly during prolonged use; while people with the latter form would not be able to exert nearly the thrust, but could keep going longer. Let's assume that things like drive to succeed and commitment to training and all those things are equal; the first group would be better sprinters and the second group would be better marathoners. So, what if, as for hemoglobin, one isoform exists at higher frequency in the black population than in the white? So What? Is this notion really so disturbing? Why should we treat it differently than, say, the difference in isoforms of Aldehyde Dehydrogenase between Whites and Asians? (Many Asians have a slow form that leads them to be sensitive to drinking alcohol) Now, no one trait is going to "make" you an athelete, or an athelete of a particular kind. It is more complex than that. But certain traits that have a genetic component make a person more suited to one sport or another. Sports represents a form of selection. You don't see many hemopheliac boxers, unless you count Jerry Quarry--but perhaps that makes the point. He was a good athelete whose skin was not tough enough to stand up to a punch, so he did not make it. Would it bother anyone if black skin was more dense with connective tissue and did not cut as easily? It wouldn't surprize me. The same selection that gave rise to greater melanin deposition (intense solar radiation) might also select for "thick" skin. So the point is that, to the extent the "races" still are not freely interbreeding (they are not, though one hopes those social tenets will fall), there will be some traits that will tend to assort with skin type. This really should not be considered racist. As long as we treat people as individuals to be viewed for their own merits, rather than the embodiment of statistical averages, we are not being racist. And we can keep open discusions of how genetics influences what we are. -tony
ir402@sdcc6.ucsd.EDU (Braun E. Brelin) (08/11/89)
In article <5264@ttidca.TTI.COM> jackson@ttidcc.tti.com (Dick Jackson) writes: >In article <3411@internal.Apple.COM> casseres@apple.com (David Casseres) writes: >> >>Professional sports has a lot of non-white players because it is one of >>the few really good economic niches open to them. But compared to the >>other niches available to whites, it isn't so hot; therefore there are not >>as many whites in pro sports as there might be. >> >We're getting into politically dangerous ground here, do I detect a hidden >agenda? I hope not. But I will boldy (foolhardily?) introduce another point, >namely that in track, blacks dominate the sprints, whites dominate the long >distances and there is rough equality around 800 meters. I can think of no >socio-economic argument to explain this. > >Dick Jackson I am puzzled by the statement that white people dominate long distances... certainly in the united states it seems that white people dominate... however, in the olympics it seems (at least to me) that it is the africans that dominate (kenyans, et. al.) braun brelin :
chiaravi@silver.bacs.indiana.edu (Lucius Chiaraviglio) (08/11/89)
In article <10659@boulder.Colorado.EDU> pell@boulder.Colorado.EDU (Anthony Pelletier) writes: >[. . .] >If there were two common variants of Myosin Light-chain Kinase, one with a >high Vmax and high Km(ATP), the other with the oposite profile, people with the >former could contract the muscle with greater velocity, exerting >greater thrust, but would fall below optimal ATP concentrations very rapidly >during prolonged use; while people with the latter form would not be able to >exert nearly the thrust, but could keep going longer. Actually, this won't do what you want. The problem is that a cell (especially a muscle cell running at full output) turns over its ATP supply in seconds. ATP is used as the common energy currency of the cell, but cells don't hoard that much cash. Instead, cells generate ATP as fast as they need it, with the supply being tightly demand-controlled. Running out of ATP does not make a muscle cell tired, but rather causes it to go into rigor (as in rigor mortis), because all the myosin heads stick to actin filaments and won't let go. Muscle cells normally prevent this from happening by means of a safety mechanism that won't let them attempt to contract when they can't make enough ATP to drive the contraction (I'm not sure of the details of this >[. . .] >So, what if, as for hemoglobin, one isoform exists at higher frequency >in the black population than in the white? So What? >Is this notion really so disturbing? Why should we treat it differently >than, say, the difference in isoforms of Aldehyde Dehydrogenase between >Whites and Asians? (Many Asians have a slow form that leads them to be >sensitive to drinking alcohol) One should be careful with talking about "fast" and "slow" isoforms of enzymes; while in this case it is fairly obvious that you are talking about the rate at which the enzyme functions, "fast" and "slow" are often used to refer to electrophoretic variants of an enzyme, whose speed of migration in an SDS-polyacrylamide gel is entirely independant of their enzymatic turnover rates! | Lucius Chiaraviglio | Internet: chiaravi@silver.bacs.indiana.edu BITNET: chiaravi@IUBACS.BITNET (IUBACS hoses From: fields; INCLUDE RET ADDR) Internet-gatewayed BITNET: chiaravi%IUBACS.BITNET@vm.cc.purdue.edu Alt Internet-gatewayed BITNET: chiaravi%IUBACS.BITNET@cunyvm.cuny.edu
pell@boulder.Colorado.EDU (Anthony Pelletier) (08/11/89)
>internal.Apple.COM> <10659@boulder.Colorado.EDU> >Reply-To: chiaravi@silver.bacs.indiana.edu (Lucius Chiaraviglio) >Organization: Department of Biology at Indiana University, Bloomington >Lines: 40 > pell@boulder.Colorado.EDU (Anthony >Pelletier) writes: >>[. . .] Me: [Oversimplified hypothetical model for difference in muscle performance] > (Lucius Chiaraviglio) writes: > Actually, this won't do what you want. The problem is that a cell [a bit more detail, mostly correct, about muscle] I won't contend with you on details since, as my posting said, I was not intending to give details. The point was that there is a rate limiting step to muscle contraction and that different forms of the enzymes involved would alter the overall rate. I trust you have no disagreements with this? I chose MLCK as a rate limiting step because it makes sense and there is evidence in mouse muscle that different isoforms lead to different contraction rate ex vivo. I agree that the ATP regenerating system (and Lactate removal) is also a key part of this (sorry for leaving them out--was trying to cut back on lines a bit). I trust you will agree that there could be allelic differences in these as well. > >>[. . .] Why should we treat it differently >>than, say, the difference in isoforms of Aldehyde Dehydrogenase between >>Whites and Asians? (Many Asians have a slow form that leads them to be >>sensitive to drinking alcohol) > > One should be careful with talking about "fast" and "slow" isoforms of >enzymes; while in this case it is fairly obvious that you are talking about >the rate at which the enzyme functions, "fast" and "slow" are often used to >refer to electrophoretic variants of an enzyme, whose speed of migration in an >SDS-polyacrylamide gel is entirely independant of their enzymatic turnover >rates! > >| Lucius Chiaraviglio | Internet: chiaravi@silver.bacs.indiana.edu Gee...thanks for clearing that up for people who were confused... But actually, since the slow form is really the slow form, either way it works! (my work on ALDH was entirely concerned with kinetics of inhibition, so I think about rates. I hope I confused noone by using an ambiguous term) -tony
mkkuhner@codon1.berkeley.edu (Mary K. Kuhner;335 Mulford) (08/12/89)
In article <9129@thorin.cs.unc.edu> barkley@unc.cs.unc.edu (Matthew Barkley) writes: >"Race" may be a handy label, even in population genetics, but it really >has no scientific validity, IMHO. How does one tell the "proportion of >Caucasian admixture"? Remember that Asian Indians are considered Cau- >casian; is that part of the admixture, too? What objective criteria do >you have for classification? Simply dividing people into Caucasian, Negro, Oriental is certainly not perfect, though it's a step in the right direction. Good objective criteria to use are the frequencies of single-gene traits--blood types, enzyme polymorphisms, immune types. You collect data from a number of unrelated genes and look for patterns of distribution. The process is reasonably objective-- math can be used to define the groups and tell whether a population (not an individual) belongs to one racial group or another. For the diabetes study, proportion of Caucasian admixture was estimated from genealogical records. There is certainly error involved in this, but when one studies a large number of diabetics the error doesn't prevent the general pattern from being visible. I would suspect, though I don't know, that people with demonstrable Oriental background were not considered in this study. >To put the whole thing into sharp focus: The singer Don Ho is said to >be of Portugese, Chinese, and Hawaiian ancestry; what "race" is he? Mixed, clearly. The existance of unclassifiable people doesn't make the classifications useless, however. If you don't like the term "race" you can use "population". >Matt Barkley barkley@cs.unc.edu >Any opinions expressed are not necessarily shared by anyone else, and may >not even be my own. How an organization can have an opinion is beyond me. Mary Kuhner mkkuhner@enzyme.berkeley.edu
kehler@ensub.Wichita.NCR.COM (Kyle Ehler) (08/12/89)
I have posted this as an article because I have been unable to reply or
forward this information to Harel B. I am using vi and net.responses for the
FIRST time, so a multitude of my errors may prevail. bear with me, please.
Healthful Houseplants
Plants that reduce the levels and severity of indoor pollution!
I recall reading a short article in a magazine called HOME MECHANIX.
In it the author (Becky Gillete) refers to a research study performed at
NASA's Stennis Space Center by a DR. B. C. Wolverton. The article's name
is THE CLEAN GREEN MACHINE on pg. 56 of the November 1988 issue.
The author lists twelve of the best plants for improving air quality in an
enclosed airspace, and some ideas for constructing an air "filter" using
the mentioned plants. Spider plants and golden pothos are the favorites
with the pothos being especially usefull in cramped quarters because they can
be "trained to climb walls" thus saving floor space. Combining a plant with
a charcoal filter and a small fan to circulate the air within the container
was illustrated along with an idea to pass the dwelling air thru a plant
filled atrium. The article reccomends a medium sized plant for every 100
square feet of space.
Twelve plants that make good air filters:
1. heart leaf philodendron *
2. elephant ear philodendron *
3. lacy tree philodendron *
4. golden pothos
5. spider plant
6. aloe vera
7. chinese evergreen
8. mini-schefflera
9. peperomia
10. peace lily ('mauna loa')
11. corn plant
12. mother in law's tongue
* - other varieties of philodendron are also good air filters
Harel, I hope this is what you were looking for. -kylezador-anthony@CS.YALE.EDU (anthony zador) (08/13/89)
>> introduce another point, >> namely that in track, blacks dominate the sprints, whites dominate the >long >> distances and there is rough equality around 800 meters. I can think of >no >> socio-economic argument to explain this. > >Neither can I. Maybe it's because of a physical difference. Did you have >a point to make? I dont really follow sports very closely, but I do have the impression that Ethiopians tend to win marathons. How does this jibe with whites dominating long distance? Tony Zador