For all the accusations of miscegenation in Southern Europe coming from American whites, it seems that they've had much more historical contact with non-Caucasoid groups than anyone in Europe ever has. Indeed, the evidence indicates that their average admixture levels, though still low, match the highest levels found in Southern Europe (Portugal), while greatly exceeding the Southern European average.
"...for many base wretches amongst us take up with negro women, by which means the country swarms with mulatto bastards, and these mulattoes, if but three generations removed from the black father or mother, may, by the indulgence of the laws of the country, intermarry with the white people, and actually do every day so marry. Now, if instead of this abominable practice which hath polluted the blood of many amongst us, we had taken Indian wives in the first place, it would have made them some compensation for their lands.... We should become rightful heirs to their lands and should not have smutted our blood...."(The Reverend Peter Fontaine
of Virginia, 1757 –
quoted in Tilton, 1995)
Statistics
Sociologist and anthropologist Robert Stuckert examined census and fertility data to estimate how many blacks in America had passed as white, and how many whites had African ancestry as a result. His statistical tables showed that during the 1940s, 15,550 light-skinned blacks per year crossed over to live as whites, for a total of about 155,500 for the decade. Based on these figures, he determined that by 1950, some 21% of whites (about 28 million people then) had black ancestry within the last four generations, and he predicted that this number would only grow in the decades to come.
Genetics"In European Americans from State College [in Washington D.C.], the west African and native American genetic contributions are low (0.7% and 3.2%, respectively)."(Shriver et al. 2003)
* * *(Van der Walt, 2003)"All nine major European haplogroups [H I J K T U V W X] were observed in our sample and did not differ significantly from a previous study of a similar North American control population (Torroni et al. 1994). In addition, a nearly identical percentage of individuals (8.2% in control subjects and 8.5% in patients with PD) did not fit into these nine predefined haplogroups and were classified as 'others.' This group most likely consists of rare European haplogroups (e.g. R or Z) or the historical admixture known to exist in the North American white population (Finnila et al. 2000; Richards et al. 2000)." [Note that R and Z mentioned in the article as examples of rare European haplogroups occur at a combined frequency of <1% in white Europeans.]
Celebrities with Amerindian AncestrySampling of white-identified celebrities who have confirmed American Indian ancestry within the past few generations:
Lumbee Cherokee
Cherokee Сhoctaw Chickasaw
Cherokee Cherokee Choctaw