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Author | Topic: Human Races | |||||||||||||||||||||||
crashfrog Member (Idle past 1496 days) Posts: 19762 From: Silver Spring, MD Joined: |
Well, a black guy is obviously different from a white guy. It's not an imaginary difference; they obviously have different skin colors. There has to be some sort of scientific explanation for that. Well, there's no difference between the melanin you get because you have a tan, and the melanin you have because you're of African descent. It's the samer chemical. I have a friend, if you looked at his skin, you'd swear he was black, Native American, or Arab at least. Really dark and dusky. Guess what? He's white. 100% Swedish. Skin color is just skin color. There's no need to associate it with race, because there's no predictive value.
Race definitely exists to some degree. Culturally, race exists. We know it's a cultural thing because no two cultures - or even people - can even agree on how many races there are. You may break it up into Asian, White, and Black, for starters, but where does that leave Arabs? Or Jews? Ask a Nazi racist if he thinks he's of the same race as a Jew. To me they're both white. But there's a big difference to them. Physically, there's no race. Sure, there's physical differences between persons that people "hang" race on, but there's so many exceptions to any rule that you propose that the whole effort is flawed - there's just no way to reliably determine race from any physical characteristics, because the variations between races are less than the variations within races. You'll always have a bunch of "white" guys who look "asian", or "asians" who look like "black" people. And you'll always have people of mixed race - where do we put them?
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Loudmouth Inactive Member |
crashfrog writes: Why? Because our racial terms betray an inherent bias - you can't be white unless you're all white, but all it takes is a little black to be black. How could such a ridiculously inconsistent system have any scientifc validity? It's ridiculous to say that it reflects "ancestry", because every human being has two ancestries, from their two parents. Yet we only refer to one of them when we talk about race. Generally it's the ancestry often viewed as inferior, in times past- which is why Halle Berry is black and not white. Totally agree Crash. I think our society is becoming more "color blind" but old biases and prejudices still seem to pop up. However, people of every color and nation still seem to put great importance in their ancestry as a way to link themselves to some history. I know Braveheart made me think of my very distant Scottish heritage even though I am an American mutt. Perhaps it is a human condition to look at everyone outside of your community as outsiders or as competition, who knows.
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Speel-yi Inactive Member |
DBlevins quoted:
quote: Skin color is not what an anthropologist is talking about when he describes race, what anthropologists use to determine race is bone structure and then more recently biochemistry. The Tamils from Sri Lanka are much more darkly complected than many people of African descent and the Tamils are caucasoid by bone structure. Further, there are some very interesting distributions of the ABO blood groups, especially in North America and this is considered to be evidence of at least several migrations into the new territory. The scarcity of Type B is very noteworthy and the absence of Type A above the Rio Grande also correlates with the Athapaskin distribution. Some genes such as skin color are extremely subject to selection and so is the presence of the various thalassemias, sickle cell anemia and favism (G6PD deficiency syndomes) all of these are heavily selected for by pathogens and so is cystic fibrosis. Things that are clinally distributed are things that approach selective neutrality such as the presence of the Inca bone, shoveled inscisors and skull shape. These are only subject to drift...not selection. Take that for what it's worth. ------------------Bringer of fire, trickster, teacher. [This message has been edited by Speel-yi, 10-31-2003] [This message has been edited by Speel-yi, 10-31-2003]
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Peter Member (Idle past 1508 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: You don't need the 'perhaps' or the 'who knows', and it'strue of all animals, not just humans. The difference is that some humans will activily seek out those that are different.
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Peter Member (Idle past 1508 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Just to get it out of the way so I'm not mis-interpreted
as racist -- I don't care whether there are races or not from a political/social vewpoint. I am concerned that legitimate features of study are shovedto one side for political reasons. People keep saying that there is more variation withinthan between -- but no-one seems to know the original source, and the percentages given are contextless. If a creationist did this would you accept it? Are the within and between comparisons on the same allelesor DNA sequences ? How is the difference assessed? It's difficult not to get hung up on what some people will dowith a biological basis for race (should one be found), but is that reason enough for not checking?
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Here is one example
This is available free online here.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Here is one example
Yu N, Chen FC, Ota S, Jorde LB, Pamilo P, Patthy L, Ramsay M, Jenkins T, Shyue SK, Li WH.
This is available free online here.Larger genetic differences within africans than between Africans and Eurasians. Genetics. 2002 May;161(1):269-74. The worldwide pattern of single nucleotide polymorphism (SNP) variation is of great interest to human geneticists, population geneticists, and evolutionists, but remains incompletely understood. We studied the pattern in noncoding regions, because they are less affected by natural selection than are coding regions. Thus, it can reflect better the history of human evolution and can serve as a baseline for understanding the maintenance of SNPs in human populations. We sequenced 50 noncoding DNA segments each approximately 500 bp long in 10 Africans, 10 Europeans, and 10 Asians. An analysis of the data suggests that the sampling scheme is adequate for our purpose. The average nucleotide diversity (pi) for the 50 segments is only 0.061% +/- 0.010% among Asians and 0.064% +/- 0.011% among Europeans but almost twice as high (0.115% +/- 0.016%) among Africans. The African diversity estimate is even higher than that between Africans and Eurasians (0.096% +/- 0.012%). From available data for noncoding autosomal regions (total length = 47,038 bp) and X-linked regions (47,421 bp), we estimated the pi-values for autosomal regions to be 0.105, 0.070, 0.069, and 0.097% for Africans, Asians, Europeans, and between Africans and Eurasians, and the corresponding values for X-linked regions to be 0.088, 0.042, 0.053, and 0.082%. Thus, Africans differ from one another slightly more than from Eurasians, and the genetic diversity in Eurasians is largely a subset of that in Africans, supporting the out of Africa model of human evolution. Clearly, one must specify the geographic origins of the individuals sampled when studying pi or SNP density. See also
Worldwide DNA sequence variation in a 10-kilobase noncoding region on human chromosome 22. Zhao Z, Jin L, Fu YX, Ramsay M, Jenkins T, Leskinen E, Pamilo P, Trexler M, Patthy L, Jorde LB, Ramos-Onsins S, Yu N, Li WH. Proc Natl Acad Sci U S A. 2001 Jan 30;98(3):779-80. Human DNA sequence variation data are useful for studying the origin, evolution, and demographic history of modern humans and the mechanisms of maintenance of genetic variability in human populations, and for detecting linkage association of disease. Here, we report worldwide variation data from a approximately 10-kilobase noncoding autosomal region. We identified 75 variant sites in 64 humans (128 sequences) and 463 variant sites among the human, chimpanzee, and orangutan sequences. Statistical tests suggested that the region is selectively neutral. The average nucleotide diversity (pi) across the region was 0.088% among all of the human sequences obtained, 0.085% among African sequences, and 0.082% among non-African sequences, supporting the view of a low nucleotide diversity ( approximately 0.1%) in humans. The comparable pi value in non-Africans to that in Africans indicates no severe bottleneck during the evolution of modern non-Africans; however, the possibility of a mild bottleneck cannot be excluded because non-Africans showed considerably fewer variants than Africans. The present and two previous large data sets all show a strong excess of low frequency variants in comparison to that expected from an equilibrium population, indicating a relatively recent population expansion. The mutation rate was estimated to be 1.15 x 10(-9) per nucleotide per year. Estimates of the long-term effective population size N(e) by various statistical methods were similar to those in other studies. The age of the most recent common ancestor was estimated to be approximately 1.29 million years ago among all of the sequences obtained and approximately 634,000 years ago among the non-African sequences, providing the first evidence from a noncoding autosomal region for ancient human histories, even among non-Africans. Which is available here. [This message has been edited by Wounded King, 10-31-2003]
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Speel-yi Inactive Member |
Had to address this, DBlevins said:
quote: For many tribes in America, you won't find any statistics like you will for the Pima because they resist having anymore studies done on their people. But if you could spend a few years among them, you'd see how many of them end up in the hospital with complications due to diabetes and the resultant strokes, heart attacks and other complications from diabetes. The "Mountian Dew" hypothesis is particularly dangerous since this simplistic idea solves nothing and actually hinders prevention. With this idea in hand, tribal governments are removing vending machines that contain Coke, Pepsi and other soda pops and replacing them with things like sports drinks, which are perceived as healthy alternatives to carbonated beverages. The only problem is that most soft drinks are sweetened with fructose and this hexose is not easily absorbed nor does it cause blood glucose levels to rise all that much. It tends to give people a bloated feeling and possibly gives rise to reflux problems since the fluid will just sit there in the gut. Sports drinks on the other hand are sweetened with glucose and this causes the blood sugar to rise rapidly. This can be handled if a person is active, but if they are sitting around and not doing much, it will shut down fat metabolism. At any rate, Type 2 diabetes is not caused by too much sugar anyway. The most likely culprit right now is hypovitamonosis D...the VDR polymorphisms seem to track pretty well with Type 1 and Type 2 diabetes. If you follow the lifestyle changes over the past half century, one thing that has happened is that people are spending less time outdoors and making vitamin D. I know it sounds whacky, but the fact remains that rickets and other vitamin D related disorders are on the rise worldwide. ------------------Bringer of fire, trickster, teacher.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Given that DBlevins said it might it not have been better to reply to the post in which he said it, or at least one of his posts, rather than a completely different one? It makes it easier to follow the thread of a discussion you are in if you can follow the reply link from your own last post rather than having to search for references to yourself in the body of the entire thread.
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Peter Member (Idle past 1508 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
The averages given show the slightly more within than
between (but nowhere near as much as quoted in other people's posts). The numbers say 118 variations for Afr. and 78 for non-Afrwith 50 variations being common. So Afr. populations have 68 unique variations and non-Afrhave 28 -- which means a difference of 68+28 = 96 That sounds like a genetic difference to me. I'm not convinced about the sample selection either. It seems to assume that Africa contains a single populationwhich includes Nigerians, Bantu, Zulu, etc. Considering the geographical size, isolating factors of geogrpahy, and cultural blocks I don't think that is reasonable. From a limited cultural and recent historical view I wouldexpect to see greater variation across African sub-populations than across European sub-populations -- with any isolated populations showing low internal variation. I'm not sure that this trend says anything about the existenceor otherwise of genetic-race -- especially since the studies look at non-coding regions, which by definition have limited impact on phenotype.
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Peter Member (Idle past 1508 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: In Ms. Berry's case I believe referring to her as black is more likelya hollywood-political thing. Eddie murphy complained one year that so few black actors got oscars, so since Ms. Berry got one the Hollywood elite can say 'See black actors DO get oscars.' In some areas in the UK in the 70's, a drop of 'white' bloodwas enough for some 'black' people to shun mixed-race people as 'white' -- you cannot get rid of ass-holes no matter what 'race' they may be. We aren't talking here about skin colour, or popular definitionsof race though -- but whether or not there is a genetic basis for 'race', and thus any biological truth to the popular concept. It may be that it's ALL cultural, but so far I'm not convinced. Doesn't mean I'm gonna set off on a Jihad though.
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sfs Member (Idle past 2562 days) Posts: 464 From: Cambridge, MA USA Joined: |
quote:You're talking about two different things here. The values cited in other posts concerned how different two individuals are. If you compare you and your next-door neighbor genetically, and then compare yourself to someone whose ancestry is on another continent, how much more different are the two of you in the latter case? The answer is, very little; on average you are only slightly more different from someone of a different ethnic background than you are from someone of the same background. In the case of Africans and non-Africans, in fact, a random African is likely to be more similar to a random European than he is to another random African. That result alone makes the concept of race pretty useless. What the numbers you quote here are talking about is the total number of variants seen in a population. The complete set of variants differs more between populations, because it includes lots of rare variants that are particular to a population but that contribute very little to average differences between individuals. The differences can be used to distinguish ethnic groups, but they don't contribute significantly to what is usually meant by races: if 0% of group A has an allele and 2% of group B has it, it seems kind of silly to say that the allele is a characteristic of group B and not of A. (This study actually exaggerates the differences between populations, by the way, by using very small sample sizes. Many of the alleles that were observed only in a single population would be observed in other populations if more individuals had been tested.) In the great majority of cases, genetic differences between populations are of two kinds: 1) the same alleles occur in both populations, but at different frequencies, or 2) one population has an allele that another doesn't, but at low frequency. There do exist fixed differences between populations (i.e. cases where one population all has one allele and the other all has a different one), and some of them may be biologically important, but they are rare.
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Peter Member (Idle past 1508 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I'm not saying that race has any useful application
potential -- just responding to the data presented as suggesting that race doesn't exist at all. The argument looks pretty thin to me, and that's all I'm saying. I'm only about 1%-5% different to a chimpanzee, but 15% differentto my nieghbour -- does that make the concept of species within primates useless ? The studies presented as supporting the assertion look atnon-coding regions (which if they ARE non-coding) don't contribute to the observed differences upon which cultural race concepts are founded. The question of whether there is a genetic-basis for racecomes down to asking are there genetically determined observable features that are different between populations but consistent within. An example that springs to mind was a study in the UK tolook at the impact of the Viking incursions on the ancestry of the British -- this was done by looking at Scandinavian Y chromosomes and characterising areas as typically scandinavian then looking for those in the UK population. It was found that across northern England, and down into the Midlandsthere was a high Viking influence, while in northern Scotland and the Scotish Isles there was none. This traces the racial origins of some of the British populationback to the Vikings. Race is even more problematic that species though -- we don'teven have the luxury of reproductive isolation to fall back on when we get confused.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Your chimp example is simply you doing what you have been criticising others for doing in this thread, giving figures without any background or explanation. Obviously the criteria used for finding 95-98% homology between human chimp DNA, such as DNA-DNA hybridisation or looking at Indels, are not those used to produce figures of 15% variation between you and your neighbour, if indeed there are any figures suggesting you are 15% different from your neighbour (are there?). Using the sort of techniques which produce the 95-98% figures for chimps you get values of around 0.1-0.05% based on data such as the HGP's estimate of 1 SNP per 1000-2000 bases, SNPs being the substantive basis for differences in annealing in DNA-DNA hybridisation.
As to your point about Race being an even more ephemeral concept than species I would tend to agree. The fact that we can distinguish certain characteristic genetic features between specific populations and that some of these, hardly surprisingly given the importance of geography as an isolating mechanism and one of the fundamental bases for racial grouping, correspond to the 'folk' concept of race does not mean that they provide backing for the whole construct of 'Race'. The point of the differences in within and between variation amongst Africans and Europeans, in as much as it has a point rather than simply being a piece of data shall we say instead the point that I would hope to make using this data, is not to show that there are no differences and we are all the same under the skin brother. The point is to show that it does not support the popular folk conception of race which lumps a vast array of highly genetically dissimilar populations together as 'black' or african and sets another population, arguably a subset of that african variation, up as in some way superior. I for one have no problem in saying that many populations have distinctive genetic differences based on a variety of biogeographical factors and various migrations and this is a reasonable use for a concept of race in biology as a delineator of these distinct biogeographic populations, but I don't think that it validates the folk concept of race that there are such distinct differences.
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Peter Member (Idle past 1508 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Agreed, and that was the point. That's why I asked for sourcematerials to find out what 'difference' estimates have been based upon. Percentiles often sound so quantitative since they are numbers,but often the qualitative/subjective aspects are overlooked. Like what was the comparison for, and on. I was simply using 15% as a stated-in-another-post within populationdifference figure. quote: As I said, getting hung up on what ass-holes will do with theirlimited understanding of a scientific concept is not at issue. It has been suggested in this thread that 'race' does not existin a genetic/biological sense. My contention is that the evidence presented to support this notion does not, in fact, support that notion. Evidence tends to indicate that there is a set of geneticallydetermined traits that are unique to different populations. This means that 'race' is a genetic phenomenon. Variation within a population is different to variation betweenpopulations and so cannot be compared in the way that it has been (IMO). quote: Folk concepts of race are often (though not always) focussedon observable difference -- if that difference is genetically determined ...
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