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Posted: 10/1/2002 7:49:35 PM EDT
in Africa, and we all started out as black?
Link Posted: 10/1/2002 7:55:03 PM EDT
We all started out as dust of the earth. Whether or not it was black dust I don't know... [url]www.reasons.org[/url] [:d]
Link Posted: 10/1/2002 9:29:46 PM EDT
Originally Posted By IMHO: Yea, lots of dramatic changes in the way we look at phylogeny in the past 20 years after a long period of relative stagnation. You'd probably do best..........
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Wow, 6 paragraphs of microbiological bullshit, & no attempt whatsoever to answer the question. Bored, or just being pedantic? (BTW, yes, we all came out of Africa.)
Link Posted: 10/1/2002 9:37:52 PM EDT
Originally Posted By TheHappyBlaster: Wow, 6 paragraphs of microbiological bullshit, & no attempt whatsoever to answer the question. Bored, or just being pedantic? (BTW, yes, we all came out of Africa.)
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Hey, I was just trying to suggest some starting points so the guy could look into it himself, OK? "Bullshit"? Do you think that I'm making this stuff up, Mungo Man?
Link Posted: 10/2/2002 3:37:19 PM EDT
Originally Posted By IMHO: Hey, I was just trying to suggest some starting points so the guy could look into it himself, OK? "Bullshit"? Do you think that I'm making this stuff up, Mungo Man?
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It sure sounded like it!
Link Posted: 10/2/2002 3:54:08 PM EDT
Well, I don't care to be thought of as being full of it, so I deleted the post. Opinions vary.
Link Posted: 10/2/2002 3:55:55 PM EDT
[Last Edit: 10/2/2002 3:56:14 PM EDT by Armitage22]
[url]http://www.geocities.com/ResearchTriangle/Facility/4118/misc/eve.html[/url]
Link Posted: 10/2/2002 3:59:58 PM EDT
Link Posted: 10/2/2002 4:07:26 PM EDT
Originally Posted By IMHO:
Originally Posted By TheHappyBlaster: Wow, 6 paragraphs of microbiological bullshit, & no attempt whatsoever to answer the question. Bored, or just being pedantic? (BTW, yes, we all came out of Africa.)
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Hey, I was just trying to suggest some starting points so the guy could look into it himself, OK? "Bullshit"? Do you think that I'm making this stuff up, Mungo Man?
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Welcome to another episode of "Short Atttention-span Theater". Sigh. I'm sorry I missed it. Did you save it? If you did, re-post it, just to annoy the locals! [:D]
Link Posted: 10/2/2002 4:13:46 PM EDT
IMHO... so are mitochondria and their nucleic acids considered resident to our ancestors populations from the get-go or at some point did they "infect" a living organism and establish a symbiotic relationship their xNA's thereby being at some point distinct from our ancestry?
Link Posted: 10/2/2002 4:17:52 PM EDT
Apparently there is now a newly discovered problem with the mitochondiral calculations that were based on a given mutation rate and the fact that mitochondira are only inherited on the female side. Apparently, there are known examples now of mitochondria being inherited on the male side, and depending on how often that happens, it can really throw off the calculation.
Link Posted: 10/2/2002 4:19:34 PM EDT
Just because life may have originated in Africa, doesn't mean that they had black skin! The increase in skin pigment is an evolutionary adaptation to protect against an overproduction of vitamin D which is produced in the human body with sun exposure, so the longer they stayed in Africa, the darker the skin became. Similarly, people from further North are more fair skinned due to less sun exposure, and shorter Summers. Or something like that!
Link Posted: 10/2/2002 4:30:35 PM EDT
Arock, Well, a theory of, a belief in, "endosymbiotic" origins of mitochondria has been around for >100 years. Take a look at "Evolution by Association" by J. Sapp (Oxford, 1994) for a solid history. We now know that, yes, mitochondria and chloroplasts are bacterial in origin: "proteobacteria" and "cyanobacteria" respectively. This is proven by rRNA data.
Link Posted: 10/2/2002 4:31:46 PM EDT
i had to write on this question for as part of my master's qualifying exams in 1995, when it was a fairly new issue. fact is, to the best we (anthropologists) know it, we did descend from a common african ancestor. the question is timing. the "eve" folks say 200,000 years ago. the fossil record (i.e. actual human remains) differs. probably happened about 1 million years ago, give or take, according to it. the sinodont (typically chinese dental pattern with shovel-shaped incisors) has existed for 1.5 million years. still there. no african teeth in china. the large browridge of australian aboriginals also well predates eve, and is still around. the eve hypothesis rests on some pretty shaky logic. they based the 200k years on the amount of change found in mitochondrial DNA per the rate of change found between humans and apes. they assumed a linearity of change, and that the human-chimp split date was accurate. this goes to the gradualism notion of evolution, which has been replaced by a punctuated equilibrium theory, so assuming linearity is kinda, uh, dumb. the argument rests also on the absolute extinction of all other maternal lines. i.e. the ancestors of eve must have a survivability advantage that they survived when all other lines became extint. as i wrote seven years ago "eve's kids must have been very smart to hide in caves while every other humanoid on the planet was killed by the alien death rays." yeah.... i also threw in some shit about population genetics that i don't remember, but it was a convincing argument to my examiners. suffice to say, eve didn;t stand up well to the argument. the eve hypothesists were a bunch of folks from UC berkely if i remember correctly, probably trying to capitalize on some notion of "race harmony" by suggesting such a recent split. not that i have a problem with race harmony, all for it, but their ideological biases became obvious with the briefest examination.
Link Posted: 10/2/2002 5:03:08 PM EDT
First, I am not AT ALL convinced that humans originated in Africa. If they did there is no way to say whether or not they were black( I doubt). Liberals love this kind of shit though but they have there own axe to grind. In the long run who cares. Mitochondria though are another subject and I find fascinating. The first great extinction on this planet was due to an increase in oxygen in the atmosphere. Cyanobacteria which had chlorophyll used sunlight for energy(photosynthesis), which was an abvious advantage, and one endproduct was oxygen. As the O2 in the atmosphere increased to toxic levels the bacteria which constituted life on this planet were poisoned. O2 did however become a way to improve the efficiency of utilization of glucose for those organisms that could do so. Eucaryotic organisms formed symbiotic relationship with either cyanobacteria or pre-mitochondrial organisms forming the eucaryotic branches separating plants and animals(simplified). This was a huge advantage as it allows an organism to get many, many times more energy in the form of ATP than would be allowable without the use of oxygen(oxidation). Hence, without mitochondria we would not exist and, in fact, poisoning our mitochondria is fatal--Cyanide is the most notable example. Over time(eons) mitochondria lost most of their own DNA as we provided most of their needs and it is innefficient to replicate unnecessary DNA. They cannot survive without us and we cannot survive without them. There is no doubt in my mind that there was an "Eve" person and that we are all related to her. Whether she was the first human or not cannot be known. Perhaps the male who mated her was the first human but mated only her or no other lines of his survived. In any event we will probably not ever know but once again liberals love the idea that the first human was a woman. Better yet if she was a black african as well. Whatever. It really doesn't matter anyhow. Fossil records as always are incomplete and virtually nonexistent in some parts of the world for certain times in the earth's history. I do find it interesting, however, that the evidence for early human dispersion centers around the Mesopatamian river valley and extends into Asia Minor and eastern europe, the Indus River valley and the Nile region. This is in keeping with the traditional view of the first humans being in the region of the Tigris, Euphrates, etc--ie biblical Eden. Once again legend has the distinct ring of truth. Some think that the first or at least original human precursors originated in Southern African and migrated northward. There is some DNA evidence to support this.
Link Posted: 10/2/2002 5:22:01 PM EDT
Originally Posted By drjarhead: First, I am not AT ALL convinced that humans originated in Africa. If they did there is no way to say whether or not they were black (I doubt).
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Aboriginal ethnicities of Africa included several yellow-skinned groups. San (Bushman), Xhosa and Hottentot among others. The great Bantu explosion of the fifteenth-seventeenth centuries overwhelmed most indigenous populations and gave the continent a more monochromatic character. Darker-skinned groups were as you allude not the only ones present.
Link Posted: 10/2/2002 5:27:46 PM EDT
Mitochondria is like hypochondria except you think you [i]might[/i] be sick all the time.
Link Posted: 10/2/2002 5:36:00 PM EDT
Just want to clear up what could potentially lead to misunderstandings: Mitochondria can and do reproduce independently of the cell, and they do have their own circular (histone free), rapidly mutating DNA. They are, though, like Drjarhead stated, dependent upon a "host" cell to live.
Link Posted: 10/2/2002 6:06:55 PM EDT
Originally Posted By DK-Prof: Apparently, there are known examples now of mitochondria being inherited on the male side, and depending on how often that happens, it can really throw off the calculation.
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DK-Prof- This might be one of the reports you're referring to , but if you haven't, check it out- An amazing story: Schwartz M and Vissing J: Brief Report: Paternal inheritance of mitochondrial DNA. NEJM 2002, 347:576-580. ..I don't wander into the Gen Discussion areas very much- How often do we get these hard-core biology nerd nuceli forming over here? :P
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