outbreeding depression refers to cases where offspring from crosses between two different different populations have a lower level of fitness than offspring from crosses between individuals from the same population. One of the ways that outbreeding depression can occur is by the breakdown of biochemical or physiological compatibilities between genes in the different breeding populations. Within local, isolated breeding populations, alleles are selected for their positive, overall effects in complementary combination with other specific alleles. Due to nonadditive gene action, the same genes may have rather different effects in different genetic backgrounds--hence, the potential evolution of locally coadapted gene complexes. Example of Switchgrass These effects can be observed in switchgrass (Panicum virgatum). While actually a single species, switchgrass comes in many different varieties, with striking differences between the different types. This genetic diversity reflects the divergent evolution and adaptation to a wide range of different environments. The different varieties of switchgrass can generally be grouped into two distinct forms: the lowland cultivars and the upland cultivars. The lowland variety tends to produce more biomass, and grow up to 2.7 meters high in favorable environments. The upland variety is generally of more northern origin, and is more cold-tolerant. Upland switchgrass types are generally shorter, less than 2.4 meters in height, and less coarse than lowland types. The upland types tend to have more vigorous rhizomes so they tend to be more sod-forming, whereas the the lowland cultivars may appear to have a bunchgrass habit. Lowland cultivars appear more plastic in their morphology, produce larger plants if stands become thin or when planted in wide rows, and they seem to be more sensitive to moisture stress than upland cultivars. One study mentions potential negetive effects on native varieties on switchgrass caused by outbreeding depression, which could be a cause for concern. "Gene flow matters in switchgrass, a potential widespread biofuel feedstock", Charles Kwit, C. Neal Stewart. Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee; and BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee "The potential for genetic pollution has been investigated in switchgrass..." "Appropriate Use of Genetic Manipulation for the Development of Restoration Plant Materials", T. A. Jones, J. G. Robins, Progress in Botany, Volume 72, Part 5, p 249-264, 2011 Example in Humans? Different groups of humans have been separately evolving for tens of thousands of years. There has been plenty of genetic divergence over this long period of time. Could it be possible that each of these separate groups of people have achieved, through natural selection, a fine-tuned balance of hormones and subtle gene expression, which could become upset by sudden change? Herbert Spencer and the Harvard geneticist Edward East, a pioneer in hybrid corn research, proposed that genetic crossing would disrupt the smooth operation of the physical and mental qualities which have been established in each race over hundreds of generations by natural selection. Carleton Coon, former professor at Harvard and president of the American Association of Physical Anthropologists, wrote: "Genes that form part of a cell nucleus possess an internal equilibrium as a group, just as do the members of social institutions. Genes in a population are in equilibrium if the population is living a healthy life as a corporate entity. Racial intermixture can upset the genetic as well as the social equilibrium of a group." An analysis of more than 3 million respondents revealed the average pay was $15.74 per hour for people of mixed race, $17.39 for black people and $22.04 for white people. This was despite the fact that 18 per cent of mixed-race people had college degrees, compared with 11 per cent of black people and 28 per cent of white people. "Can the 'one-drop rule' tell us anything about racial discrimination? New evidence from the multiple race question on the 2000 Census", Robert W. Fairlie University of California, Santa Cruz A study by J. Richard Udrys National Longitudinal Study of Adolescent Health, which sampled a random, nationally representative school-based sample of U.S. adolescents in grades 7 through 12, during 1994-1995, showed an increase in behavioral problems amongst mixed-race children, as well as significantly higher rates of asthma, and generally poorer health. Another interesting finding was that mixed children that had a black parent were significantly more likely (63% more) to have skin problems. J. Richard Udry, Janet Hendrickson-Smith, Carolina Population Center, University of North Carolina at Chapel Hill, 2003 Anita Patel,M.D., transplant nephrologist at Henry Ford Hospitalfound that kidney transplants between individuals of the same race had statistically betteroutcomes than transplant across different races. http://www.time.com/time/health/article/0,8599,1993074,00.html
This is absolute racist BS. There aren't any significant differences between humans. The only genetic differences are purely cosmetic such as height (more dependent upon diet than anything else) and skin color, hair color and eye color (afffected by environment). There are no genetic differences related to primary organs such as hearts, lungs, kidneys or brains. There is only "one race" on this planet and it is the "Human Race" (Hu).
I suppose "race" is a relative term— just like cytotype is a relative term used to group the different varieties of switchgrass into two convenient groups. Here is an essay that discusses whether it is appropriate to classify different genetically-diverse human populations into racial categories: http://www.charlesdarwinresearch.org/TaxonomicConstruct.pdf Just so you are aware, there is simple genetic testing that can be used to distinguish between different races with complete accuracy:
IMHO This is something a Forum of integrity should not think of allowing , however disguised in mumbo jumbo scientific terms . It is a desperate attempt to make out and out Racism seem intellectually respectable . Shame on the OP and the Forum for his continued presence here .
I do not see what is wrong with pointing out the obvious fact that there are different races of humans, and questioning whether there could potentially be some disadvantages to mixing.
A race means absolutely nothing . Take for example the Lemba people , they live in western Africa and they are black but genetically they are of Semitic origin , they moved from Eurasia into Africa and through the passage of time their skin became black because in Africa white skin is absolutely useless . Racial characteristics are very very temporary . There isn't enough genetic variation . All non Sub-Saharans come from a small group of Africans that left the continent ~70.000 years ago , if your "hypothesis" holds any water preventing black Africans from mixing with each other will solve 99% of the "issue" . If you do a little research you will find out that people from the same African village are (by chance) hold more genetic variation than a Spaniard , a Mongol and a native Australian do.
In some ways at least I believe this is true. Natural selection can cause evolutionary changes much faster than many people realise. Simple yet profound genetic changes can occur over the period of only 5 generations. These changes are only statistical of course: height, strength, disease resistance, behavioural propensities, and to some extent intelligence. There are different types of genetic variation. And I really doubt there is as much genetic variation between two norwegian men as there are between a norwegian man and an african man. Of course, we all know there exists significant variation between males and females— a single chromosome, out of 46, is enough to cause these important differences. So in one way, two men of different races share something in common that a male and female of the same race do not. You are welcome to provide a link to any specific scientific studies that support your viewpoint.
Variation is the outcome of 2 major factors a) Time and b) Numbers , as it is common knowledge Africans - and specifically 2 populations , one from the Rift valley and the Bushmen- are the oldest , how do we know it? because we all have their genetic markers while they have none of ours ! so they had time on their side to "build variation". From what modern genetics have proven all non Sub-Saharans come from a small group of people that probably walked from the horn of Africa to what today is Yemen , small group of people means that they also had numbers on their side ( see link 3) so numbers + time = greater genetic variation . this is a good read to learn the basics and some more this is indicative too but i couldn't track the original paper back in Cambridge university . This explains much about population numbers of ancestral population and the group that left Africa .
What you are showing (and I do not disagree) us that there is much genetic diversity within the Black race, not other races. So it is okay if you want to say that there is more genetic diversity between a Nigerian and a Kenyan than between a Spaniard and a Japanese person. That there are some significant differences between East Africans and West Africans are well known. Take for instance the dietary tolerance to milk. West Africans are, for the most part, intolerant to dairy, while many East Africans drink milk as a primary food source. There is even one East African ethnicity (Maasai) that survives almost entirely only on milk and blood from their cows! (not meat, the animal is not killed) Here you can see them "harvesting" the blood: Eskimos, for instance, are also adapted to surviving in the absence of carbohydrates, eating rather seal blubber as their primary source of energy. The eskimo people have an enlarged liver to handle the additional stress this places on the body's metabolism. http://www.jbc.org/content/80/2/461.full.pdf
Lets not forget to include the IQ statistics showing how blacks have the lowest level IQs among the other races. That fact seems to merge in rather well with the other scientific discoveries from your OP.
I do not feel this comment was necessary for this thread. I am simply trying to point out racial differences, not berate a group of people. I actually do not think that IQ differences are very representative of racial differences. While there certainly is a statistical correlation between race and intelligence, I do not feel it is a fundamental correlation. Intelligence levels in a certain human population can change very much within a relatively short evolutionary time period, of perhaps around 30 generations. Natural selection can alter statistical variances much faster than many people realise. In other words, the Northern Europeans of the Viking age where not as intelligent as the ones today.
Exactly, vikings, or as we know them today as scandanavians, are the most likely ppl to commit suicide. Like how retarded is that for human progression?!
Yes, odd that political correctness hasn't (yet) ruined the career of a man trying to investigate the science of genetics. Such a subject is taboo, because society says that the only difference is skin color, and we don't need to know any more <covers ears and yells LA LA LA LA>. Seriously people, are you going to let your own preconceptions prevent you from hearing anything on the subject without the knee jerk reaction of "Shut up! That's racist to study genetics!" Unless, of course, it's to "prove" what you already wanted to believe.
Besides the obvious link to alcoholism, there is a actually a positive correlation between suicide rates and intelligence. Japan is the nation with one of the highest suicide rates, and the Japanese statistically have the highest IQ rating of any nation. Jan-Emmanuel De Neve, of University College, London found a correlation between the gene that encodes the serotonin-transporter protein and reported happiness levels between different races. The happiest where Blacks, followed by Hispanics, then Whites, with the least happy being Asians. This is in the exact opposite order as the IQ levels for these races. The races with higher IQ's are less happy. http://www.economist.com/node/21532247 Actually suicide rates in Scandinavia are not really as high as everyone thinks. The main reason is probably just the long winters and short hours of daylight.
Not really, the most likely explanation is that they intermarried with the local population. Interestingly enough, they still possess genetic markers that are specifically jewish on the Y chromosome. Major changes in phenotype take thousands of years. Lactose intolerence is still present in Asian and African families living in the US even if they came over in the 1700s. This despite the fact that milk drinking is common in the US. Lactose intolerance is caused by the lack of a lactase enzyme in adulthood. It's literally ONE mutation. hundreds of years and it still hasn't happened. Skin tone is determined by more genes than just one. So no, it's not as simple as move to the tropics and become black. well yes and no. They certainly vary, but isolation tends to concentrate a few genes in a population. So the reason that you see eye-folds in asia is that asians who have eye-folds were isolated from Caucasians and Africans who didn't. Had that not happened the trait wouldn't be visible.
So why do people usually marry others that are more ethnically/racially similar to themselves? Is this always a conscious choice? http://faculty.chicagobooth.edu/emir.kamenica/documents/racialPreferences.pdf
1. Outbreeding depression is a concept of selective breeding. 2. Plus that study is nearly 20 years old. The are nearly half a billion (or more) mix people on this planet (Mostly in South America and Central Asia) and Africa has the highest rates of asthma which is most populated by pure blooded blacks. http://en.wikipedia.org/wiki/Asthma#Epidemiology
It's not taboo. What are you talking about? Watch this video from 4:25 and onward. http://www.youtube.com/watch?v=A8RefZ1Hcvo&nomobile=1 And this. http://www.youtube.com/watch?v=V0DIUCjLQls&list=FL8MMoPi-EvKwAY0Z8b6SZ0w&index=24&feature=plpp_video And about political correctness. http://www.youtube.com/watch?v=h-YaNCs1m7Q&feature=plcp
I think i said Africans not blacks , there are several black people in the west that genetically are mostly European , skin pigmentation isn't a clear indication of genetics . To take this a big farther Australian , Melanesian and Negrito (Adaman Islands / Philippines) populations hold same variation with non Sub-Saharans . It isn't about political correctness but about every single credible genetic research of the last +20 years that make this guy a laughing stock among his colleagues. "Still" ? heh Y chromosome markers are passed from father to son and they stay there unchanged , this is how geneticists are able to trace human lineage back to a couple of African populations. I am far from a specialist but i think you are missing some important info here , you can be lactose intolerance and survive yet melanin's main role is to block ultraviolet radiation , i don't remember if it is UVA or UVB but one of them goes deep into the skin and destroys a protein crucial for the development of bones in the human foetus , chances are that those who didn't produced enough melanin simply died out . It is a possibly reversed situation with ice age Europe where those who didn't turn white died out because of rickets . And about lactose thing , i am southern European and i am 100% intolerant , we are 4.000 years in this place and still this mutation didn't happen! http://www.ucsd.tv/search-details.aspx?showID=16926&subject=sci Evolution of Human skin Pigmentation lecture by Dr N. Jablonski First of all there isn't any Caucasian race, Homo Georgicus died out long before we left Africa ! To check out "isolation" refer to any map showing Haplogroups ( they represent human migrations ) . Isolation is an evolutionary factor when it causes genetic drift , humans are not drifted in any way . Oriental eyes have one big advantage when compared to different ones , they don't get blind by the reflection of light on the snow , i 'd say this is an indication that those people spent some time in Siberia.
Sure, like there must be a correlation between iq and height. The shorter you are the more intelligent obviously. Japanese are short and have the highest iq therefore iq is directly related to height. So this means that genetically, tall ppl are the least intelligent ppl this is ever so clear now. This must mean that midgets are geniuses!!!!!!! I think you are making ground breaking scientific discoveries here son!
"Over millions of years, man has become the very paradigm of animals, but we must take care not to alter what nature has taken so long to forge, or risk being burned by the very fires of creation." ending narration The Outer Limits "New Breed", 1995
