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Author | Topic: Human Races | |||||||||||||||||||||||
Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: ...the reason is not linked to greater difference within andbetween populations though. quote: So distinctive differences in physiology, bone stucture, muscleattachment, etc. are just random coincidence and not the result of some past selective pressure? quote: So a population that has been subject to the same selectivepressures will NOT share a set of traits? And two different populations living in environments withdifferent selective pressures won't diverge (even remotely ... perhaps I can call it nano-evolution )? If there was concensus in the west for a spherical earth fortwo thousand years, how is that people thought Columbus was going to fall off the egde if he went too far? Sure, the Greeks and other ancient races knew, but in Europeas recently as, what, three - four hundred years ago, the majority opinion was Earth was flat. Consensus isn't enough. It can be shaped by political factorsand fear of reprisal. I'll restate my position (hopefully with any contradictionsremoved, and consider this my thinking even if my meadering thought processes have obfuscated my thinking in previous posts). 1) Cultural racial membership is defined by the members of aperceived race (not by outsiders). The UK government is using a 'self-declaration' race categorisation, and the US hospital services have performed studies that show, by-and-large, that self-determined racial categorisation matches standard admission rankings. 2) Cultural racial associations are linked to the historyof the cultural race. 3) Cultural races originate in localised geographic regions. Eachgeographic region will present somewhat different survival challenges. 4) Extant phenotypic traits that interact with the environment will,over time, be shaped by the environment. These traits are, by definition, heritable. 5) If there is a noticeable difference in the pehnotypic traitsof one group compared to another, then this must be identifiable in the coding segments of the genome. We, as humans, are observably different.Those differences are heritable. Those differences are what cultural racial concepts refer to.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
And what about ....
Nature - Not Found "They discovered that the most recent common ancestor of everyone in the sample group lived in Africa 171,500 50,000 years ago. They also found a significant branch in the tree that separates most Africans from non-Africans. This genetic divide probably represents an exodus of people from Africa that took place 52,000 27,500 years ago."
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: So your rejection of the traits being adaptive is as incorrectas my suggestion that they are. Can we positively identify ANy traits as adaptive except bya significant amount of hypothesising? quote: And in regard to a biological basis for race, this is more prothan contra. If geographic separation subjects different groups to differentsets fo selective pressures, then the populations that are affected by those pressures will share trait sets that populations elsewhere do not have. quote: Fair enough ... doesn't detract from concensus being a poormetric for a theory. How about a geocentric solar system then ... or bleeding beinga beneficial therapy ... or ...
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Sorry, mis-interpreted the above as you saying that theyweren't rather than we don't have evidence that they are. quote: Darwin didn't have the luxury of genetic evidence, and yet he couldstill infer adaptive traits from observation of traits wrt environment ... isn't that sufficient? If a trait provides a benefit of some kind in the environment where it is the norm? Isn't the emergence of differentiation between two populationsof the same species in different locations required by evolutionary theory ... and it's absence an undermining of such? quote: Inuit :- live in harsh, cold environment with limited vegitation. Kalahari Bushmen :- live in harsh, desert environment some game, somefruit/nuts/edible roots. Celts :- Originated in cold, wet hilly location unsuitable for muchagriculture. The locations on earth are many and varied, and the peoples whocome from different locations are observably different, but consistent within group. quote: That's all I was saying. Consensus was raised as though thatmade it true ... I am unconvinced by the suggested evidence.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
'Genetic approaches to understanding human adaptation to altitude in the Andes.'
Talks about the difficulty of determining whether or nota trait is developmental or 'built-in'. Is that the same as inferring whether a trait is adaptive ornot, if one already knows that the trait is genetically linked (based of heritability, for example)? If a heritable trait confers an advantage, and only occursin individuals who trace their family origins back to the same location is that insufficient evidence of an adaptive trait? Off topic maybe?
quote: Who said anything about genetically identicle ... since when didconsistent mean the same? The paper you cited is talking about 'rare mutations'. One wouldhardly classify a drosophila with stunted wings as anyhing but a mutant drosophila, why change the 'rules' for humans? If you have a whole bunch of red-eyed ones and a whole bunchof white-eyed ones of the same species they are referred to as strains (aren't they) ... why change the 'rules' for people?
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Isn't it likely that light skin was selected for in
low-sunlight regions because darker skin reduces (in the sense that you need more light to do it) Vit-D synthesis ? Otherwise the 'western europeans' would range in skin toneacross the ful spectrum rather than in the lighter end, surely. [This message has been edited by Peter, 12-05-2003]
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: This implies that regionally associated, heritable traitsjust emerge at random, and leads to the populations originating in different regions came into being independently of one another. Genetic evidence points to a migration from Africa coupled withsome populational bottle-necks. If the population that headed out-of-Africa where a single populationthen according to what has been suggested in this thread they would be pretty homogenous. That populations in different regions are observabley differentand these differences are heritable means that something promoted particular phenotypes in the different regions. The different phenotypes are suggestive of a divergence amongstthe original migrant population. quote: Are you saying that the ToE's dependence on differentiationwithin a species depends on the above, or whether it happens or not depends on the above. Some researchers are suggesting that the emergence of modernhumans and apes did not occur as a distinct split, but was generated over time from an inter-breeding population with increasing degrees of differentiation. quote: Inuit are genetically pre-disposed to obesity (i.e. fat deposition)which is beneficial in a cold climate, and require less calcium in their diets (recommended calcium levels given to Inuit children can cause hypercalciuria at significantly higher rates than seen in non-inuit). They also possess lower incidence of genes associated with cardio-vascular disorders, which is beneficial if you want to survive longer with higher body-mass-index. quote: Agreed, although they have no name for themselves (or none thatthey are willing to divulge), but have come to accept the term (somewhat). The intrusion of Bantu herders into their hunter-gathering lifestylepre-dates western interaction with the region, but is not overly indicative of inter-breeding between the two different tribal cultures. There is some suggestion that all click-language speakers arerelated. http://www.marylandresearch.umd.edu/issues/fall2003/dna.html has: "The connection between populations who speak a click language, the language spoken by the Africans in the film "The Gods Must Be Crazy." The DNA shows that different peoples who use click language but live hundreds of miles apart, may be related. Says Tishkoff, "We have been able to show, for the first time, that the Sandawe of East Africa and bushmen from the south of Africa and the southern bushmen of Botswana, Namibia and South Africa share a recent common ancestry, within about 35,000 years. We speculate the southern bushmen originated in East Africa, and that they both are remnants of a very old group of hunter-gatherers, perhaps the earliest ancestors of modern humans." Which admittedly doesn't say anything about, well, anything in detailbut indicates that there is a genetic means of identifying 'Bushmen'. As for the celts --- well OK, even during the time of the RomanEmpire that was a bit tenuous (and I was thinking of Wales ). Interestingly there is a review onhttp://www.2think.org/cavalli-sforza.shtml which is a little schizophrenic. It states that "The variation among individuals is much greater than the differences among groups. In fact, the diversity among individuals is so enormous that the whole concept of race becomes meaningless at the genetic level", but just prior to that says "once the genes for surface traits such as coloration and stature are discounted". So once we discount the genes for the traits upon which racialdistinctions are usually made, suprisingly, we find no genetic evidence for race. Does that not seem a little, well, odd. Other selected quotes are :-"What the eye sees as racial differences - between Europeans and Africans, for example - are mainly adaptations to climate as humans moved from one continent to another. " "Those findings, plus the great genetic distance between present-day Africans and non-Africans, indicate that the split from the African branch is the oldest on the human family tree" "All Europeans are thought to be a hybrid population, with 65% Asian and 35% African genes" You cannot have it both ways ... there are either geneticallyobservable differences that allow us to trace humanity's origins back to Africa, or there are no significant differences between races that can be seen in the genome.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: It's actually an issue that I find somewhat confusing. I assume by 'curly hair' you mean the very tight curls associatedmost often with those of African or Afro-Carribean descent, rather than the 'naturally curly hair' of Charlie Brown's would-=be girlfriend. But eye colour also is a problem for me. From people I know with mixed-raced parents, they all seem to havethe dark eyes and tight curls of that side of the family. If that is the case all of the time it would suggest that the genetic controlling this feature are dominant (blue eyes are a recessive feature I believe). Why have recessive features become dominant in somepopulations? How could that happen with significantly inter-breeding gloal populations?
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
What you have said perturbs me.
There is a suggestion that because somethingexists in a continuum we must negelect differences between 'items' in two different points of the continuum ... like red-light is just electromagnetics isn't it, no different from UV or X-rays. If the polarised objection to a genetic basis for race ispolitically motivated, then it is as objectionalble as using race for political ends, or promoting creation science in schools. All of the citations show that differentiating between differentcultural members IS possible at the level of the genome. Even with the inter-breeding between Zulu, Bantu, and Khosian people, from fairly narrow geographic ranges. How can one posit differences between different culturallydivided groups as evidence against race? There are objectionable associations with racial determination,and I cannot see any reason that racial differentiation should matter on a day-to-day personal basis. It has interest in tracing human origins, perhaps. My problem in this thread is not that I want there to beracial distinctions, but that I feel that denial of them is driven by politics and not by scientific inquiry.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Sorry if I implied that it was your (or SFS's) motivation,not intentional there. My concern is that there is a great push for there beingno genetic basis for race which doesnt seem to tie up with what the people who are claiming that are saying elsewhere in the same papers. If there is no race, how CAN you tell that there are differencesin genomes between African and non-Africans, or that Australian aborigines are not closely related to modern indigenous Africans. You cannot make ANY arbitrary geographical demarcation and finda genetic correlation. To take an example from sfs's reply to the same post that you are replying to) look at a city. Say Dublin, or London, or Paris. There is NO genetic marker available for such a populationbecause there is a very wide range of lineages that originate in different geographioc locations. Likewise if the geographic area is too large, or divided by geological barriers this will not be the case.
quote: You cannot replace 'race' with 'almost any arbitrary grouping' unlessI am mis-understanding your use of arbitrary. Take a city population and study their genetic diversity andit will be all over the map. Sub-divide the same group based upon assumed racial origin and you'll start to see correlations. If this were not the case genetic distance would not correlateto geographic distance. Perhaps my use of the word divergence is a little strong,but there is diversification. If you accpet that the genetic evidence points to an out-of-africa origin, then you have to accept diversification. That diversity is forged geographically, and most concepts of'race' correlate with geographical origin.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: No, you demonstrate that neither the Bantu-speeaking not Khosianspeaking villages are representative of the races in question. The history of this relationship, in terms of inter-tribalmarriages, changes the situation. The genetic distance between one Khosian speaking villageand another (assuming one is relatively isolated) provides a measure of 'out breeding'.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Those who, according to at least one of the papers referencedduring this discussion, share alleles that are not present in Europeans and Asians. There are aprrox. (without looking back) 20 of these.
quote: What has this to do with it? If you have a group of populations with no reproductive barrieryou can get highly embedded crosses, that doesn't mean that a concept of race is non-existent. I am not arguing that you won't get convergence with significantinter-breeding, I'm saying that that has not happened to a sufficient degree to claim that there is no biological basis for race. quote: This doesn't make sense, logically. If, in one region you have sufficient inter-breeding to comletelyobscure all traces of original lineages, then in that location you will have a new, unique trait-set, since the likelihood of haveing the exact same mix elsewhere would be very small. So the 'new' lineage would have a geographically traceable origin. If this has not happened sufficiently yet, then you would findtraces of the lineage origins in any case. You cannot start a lineage if you live on opposite sides ofthe world (unless you have an inter-national sperm/egg bank I suppose). quote: Not paying any attention to it and not 'subscribing' to it aredifferent. I doubt that there is a society anywhere that doesn't have an ingrained concept of race ... socially constructed yes, but there. If Out-Of-Africa is incorrect, then human populations emergedseparately in separate locations, and the diversification would be even more pronounced, since it would be older. quote: Well, yes. No matter how much vagueness there is in a concept of race,ultimately there is a geographic component. One doesn't think of the bloke up the steet as of a different race, unless he's different from all the usual residents ... and the only reason that someone would be that different are unfortunate circumstances of disease or other disability, or because they come from somewhere else ... or their family line comes from somewhere else. There are people in the US who think of themselves as Irish-American,or African-American ... almost all racial concepts have a geographic component (even Dubliners or Berliners). quote: Outside of the US, UK, and Australia pretty much all over. Western Europe has a large degree of inter-mingling, but lessso than the colonies ... but move to the Indian sub-continent or mainland Asia, or S.America (outside the large population centres) or Amongst the Native American tribes, or African tribes ... and the number of inputs will be MUCH less. quote: It's not invalid ... but that ISN'T biologically based. You seem to be suggesting that global inter-breeding has beencommon across the ages ... I've not seen historical evidence of this. Human societies have been fairly xenophobic, on the whole.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: So, if you exclude all the bits that make us differentwe are the same ... Black and white is too broad, but the above says that thedifference has to be specifically excluded. If there is significant inter-breeding for a number of generations why expect there to be clear distinctions left. This is not the global norm. Added by edit (so as not to do another post): Won't Portuguse have 'African' ancestry even inportugal too? Certainly in the southern parts, where the Moors held sway for some considerable time ... doesn't that history conflate matters? There is also mention of 'African allellic markers', andof Brazilian people falling between the European and African AA1 values. Doesn't that mean that there are races, otherwise one could notspeak of allelic markers. [This message has been edited by Peter, 12-15-2003] [This message has been edited by Peter, 12-15-2003]
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: That's more or less what I HAVE been saying.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Thanks, I'll take a look.
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