Originally posted by Raven
If you like to think of it more scientifically, then maybe one should consider this fact. According to DNA structures, every human being is less then a tenth of a percent different from any other human on earth. In other words we are all 99.9% the same in structure regardless of sex or race. It is only in that tenth of a percent that we are different.
From http://home.comcast.net/~neoeugenics/tab.htm
Diamond offered a more colorful version of an argument advanced in 1972 by Richard Lewontin, a Harvard University geneticist. Lewontin had become convinced that virtually all meaningful differences between races are either random or culturally determined. Based on his review of the available data, he concluded that only a tiny fraction of the differences between individuals could be considered "racial." In other words, Lewontin maintained that the differences that separate "races" are little more than what distinguishes two random fans at a World Cup match--statistically nothing, genetically speaking. The article, published in the prestigious journal Evolutionary Biology, amounted to a frontal attack on the concept of race.
For sure genetic differences between any two individuals are extremely small in percentage terms. Coming from a geneticist, rather than a sociologist or anthropologist, Lewontin's article had enormous influence, although not everyone was convinced. Lewontin's finding that on average humans share 99.8 percent of genetic material and that any two individuals are apt to share considerably more than 90 percent of this shared genetic library is on target. Interpreting that data is another issue, however. Lewontin's analysis suffers both scientifically and politically.
Although the politics of a scientist is not necessarily an issue in evaluating their work, in Lewontin's case it is crucial. According to his own account, his sensibilities were catalyzed by the civil rights movement of the 1960s. He made it very clear that his science was in part a mission to reaffirm our common humanity. To geneticists and biologists with less of an avowed agenda, Lewontin appeared to leaven his conclusion with his personal ideology.
From a scientific perspective, Lewontin and those that have relied on his work have reached beyond the data to some tenuous conclusions. In fact the percentage of differences is a far less important issue than which genes are different. Even minute differences in DNA can have profound effects on how an animal or human looks and acts while huge apparent variations between species may be almost insignificant in genetic terms. Consider the cichlid fish, which can be found in Africa's Lake Nyas. The cichlid, which has differentiated from one species to hundreds over a mere 11,500 years, "differ among themselves as much as do tigers and cows," Jared Diamond has noted. "Some graze on algae, others catch other fish, and still others variously crush snails, feed on plankton, catch insects, nibble the scales off other fish, or specialize in grabbing fish embryos from brooding mother fish." The kicker, these variations are the result of infinitesimal genetic differences--about 0.4 percent of their DNA studied.
In humans too, it is not the percentage of genes that is most critical, but whether and how the genes impact our physiology or behavior. Diamond mused that if an alien were to arrive on our planet and analyze our DNA, humans would appear, from a genetic perspective, as a third race of chimpanzees. Although it is believed they took a different evolutionary path from humans only five million years ago, chimps share fully 98.4 percent of our DNA. Just 50 out of 100,000 genes that humans and chimps are thought to possess--or a minuscule 0.3 percent--may account for all of the cognitive differences between man and ape. For that matter, dogs share about 95 percent of our genome; even the tiny roundworm, barely visible to the naked eye, share about 74 percent of its genes with humans.
Most mammalian genes, as much as 70 percent, are "junk" that have accumulated over the course of evolution with absolutely no remaining function; whether they are similar or different is meaningless. But the key 1.4 percent of regulatory genes can and do have a huge impact on all aspects of our humanity. In other words, small genetic differences do not automatically translate into trivial bodily or behavioral variations. The critical factor is not which genes are passed along but how they are patterned and what traits they influence.
Lewontin did collate genetic variability from known genetic markers and find that most of it lay within and not between human populations. Numerous scientists since have generalized those findings to the entire human genome, yet no such study has been done. Now it is believed that such an inference is dicey at best. The trouble with genetic markers is that they display "junk" variability that sends a signal that variability within populations exceeds variability between populations. However, the "junk" DNA that has not been weeded out by natural selection accounts for a larger proportion of within-population variability. Genetic makers may therefore be sending an exaggerated and maybe false signal. In contrast, the harder-to-study regulatory genes (that circumscribe our physical and athletic abilities) signal that between-group variability is far larger than has been believed. In other words, human populations are genetically more different than Lewontin and others who have relied on his work realize.
