According to a genome-wide study by Bryc et al. (2009), the overall ancestry of African Americans was formed through historic admixture between West/Central Africans (more frequently females) and Europeans (more frequently males). Consequently, the 365 African Americans in their sample have a genome-wide average of 78.1% West African ancestry and 18.5% European ancestry, with large variation among individuals (ranging from 99% to 1% West African ancestry). The West African ancestral component in African Americans is most similar to that in present-day speakers from the non-Bantu branches of the Niger-Congo (Niger-Kordofanian) family.[13][nb 1]
Correspondingly, Montinaro et al. (2014) observed that around 50% of the overall ancestry of African Americans traces back to the Niger-Congo-speaking Yoruba of southwestern Nigeria and southern Benin, reflecting the centrality of this West Africa region in the Atlantic Slave Trade. The next most frequent ancestral component found among African Americans was derived from Great Britain, in keeping with historical records. It constitutes a little over 10% of their overall ancestry, and is most similar to the Northwest European ancestral component also carried by Barbadians.[156] Zakharaia et al. (2009) found a similar proportion of Yoruba associated ancestry in their African-American samples, with a minority also drawn from Mandenka and Bantu populations. Additionally, the researchers observed an average European ancestry of 21.9%, again with significant variation between individuals.[154] Bryc et al. (2009) note that populations from other parts of the continent may also constitute adequate proxies for the ancestors of some African-American individuals; namely, ancestral populations from Guinea Bissau, Senegal and Sierra Leone in West Africa and Angola in Southern Africa.[13]
Altogether, genetic studies suggest that African Americans are a multiracial people. According to DNA analysis led in 2006 by Penn State geneticist Mark D. Shriver, around 58 percent of African Americans have at least 12.5% European ancestry (equivalent to one European great-grandparent and his/her forebears), 19.6 percent of African Americans have at least 25% European ancestry (equivalent to one European grandparent and his/her forebears), and 1 percent of African Americans have at least 50% European ancestry (equivalent to one European parent and his/her forebears).[157][158] According to Shriver, around 5 percent of African Americans also have at least 12.5% Native American ancestry (equivalent to one Native American great-grandparent and his/her forebears).
The Genetic Ancestry of African Americans, Latinos, and European Americans across the United States Katarzyna Bryc,1,2,∗ Eric Y. Durand,2 J. Michael Macpherson,3 David Reich,1,4,5 and Joanna L. Mountain2
2014
The Genetic Landscape of the US
Patterns of Genetic Ancestry of Self-Reported African Americans Genome-wide ancestry estimates of African Americans show average proportions of 73.2% African, 24.0% European, and 0.8% Native American ancestry (Table 1). We find systematic differences across states in the US in mean ancestry proportions of self-reported African Americans (Figure 1 and Table S2). On average, the highest levels of African ancestry are found in African Americans living in or born in the South, especially South Carolina and Georgia (Figure 1Aand Table S3). We find lower proportions of African ancestry in the Northeast, the Midwest, the Pacific Northwest, and California. The amount of Native American ancestry estimated for African Americans also varies across states in the US. More than 5% of African Americans are estimated to carry at least 2% Native American ancestry genome-wide (Figures S1 and and1D).1D). African Americans in the West and Southwest on average carry higher levels of Native American ancestry, a trend that is largely driven by individuals with less than 2% Native American ancestry (Figure 1B). With a lower threshold of 1% Native American ancestry, we estimate that about 22% of African Americans carry some Native American ancestry (Figure S2).
The Genetic Structure and History of Africans and African Americans Sarah A. Tishkoff et al, 2009
The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals.
posted
Its 24%. the higher figure is from a 2014 study that sampled 5,269 self-described African Americans, the 2009 study used a much smaller sample (98).
Posts: 949 | From: England | Registered: Oct 2015
| IP: Logged |
posted
Most studies I read consistently say around 12%. And I'm surprised these two studies have only around 70% African when most I read have 80% African.
Posts: 1891 | From: NY | Registered: Sep 2014
| IP: Logged |
quote:Originally posted by BlessedbyHorus: Most studies I read consistently say around 12%. And I'm surprised these two studies have only around 70% African when most I read have 80% African.
No the point of the thread is that the second earlier Tishkoff article says Niger-Kordofanian 71% and other African populations 8%
quote:Originally posted by BlessedbyHorus: Most studies I read consistently say around 12%. And I'm surprised these two studies have only around 70% African when most I read have 80% African.
the total is 78% African for African Americans according to that article, close to your 80%. In your 80% there is a remainder of 20% not 12%. Looking the the Tishkoff, 78% African the remainder is 22% non African.
The Genetic Structure and History of Africans and African Americans Sarah A. Tishkoff et al, 2009 "The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals."
what's the total? 71+13+8= 92, not 100% I will have to look over the article again , there is another 8% unaccounted for
Looking at the other article, 2014, Bryc et al 73.2% African, 24.0% European, and 0.8%(Native) = 97.28%, that is a smaller unaccounted for 2.72%
Also, for Mr. Cass, if one has a correct average then if the sample size is increased the percentage remains the same. One cannot assume a larger sample size yields more accurate results because there might be different methodologies which are causing the difference.
Posts: 42919 | From: , | Registered: Jan 2010
| IP: Logged |
posted
The 2014 study sampled AA's from all over the US, hence they have a diagram about regional admixture in every US state (it differs). The 2009 study used a sample that did not cover the whole US and much smaller sample size.
The average AA is almost 1/4 European. This is supported by morphological studies, AA's deviate substantially from West African craniometric means.
Posts: 949 | From: England | Registered: Oct 2015
| IP: Logged |
posted
What exactly IS an African American really? They've been going with the pseudo-scientific hypodescent rule, more commonly known as the "one drop" rule over there since the 17th century, so what exactly constitutes an African-American today? I'm willing to bet that if they limited the samples based on those who express phenotypical traits common to their "parents" in continental Africa, the results would be much different. As it is today, a biracial person like Jesse Williams could submit a DNA sample, label himself as "African American", and the data extracted from his sample would have to be included in the results. People from the south are generally more African that people from the north, and those who come from the Carolinas-region (gullah-gechee etc) are even more African. There is no criteria for whom is & isn't an African American, everybody "counts" as long as they self-identify as being "African American". So how can these results be accurate in any way, shape or form?
Posts: 117 | From: Earth | Registered: Feb 2014
| IP: Logged |
quote:Originally posted by Snakepit1: What exactly IS an African American really? They've been going with the pseudo-scientific hypodescent rule, more commonly known as the "one drop" rule over there since the 17th century, so what exactly constitutes an African-American today? I'm willing to bet that if they limited the samples based on those who express phenotypical traits common to their "parents" in continental Africa, the results would be much different. As it is today, a biracial person like Jesse Williams could submit a DNA sample, label himself as "African American", and the data extracted from his sample would have to be included in the results. People from the south are generally more African that people from the north, and those who come from the Carolinas-region (gullah-gechee etc) are even more African. There is no criteria for whom is & isn't an African American, everybody "counts" as long as they self-identify as being "African American". So how can these results be accurate in any way, shape or form?
If you were assigned the task of analyzing the DNA of the African American population but you don't think self identification is accurate than to what percentage, in your opinion, does a person have to be, to be African American?
Posts: 42919 | From: , | Registered: Jan 2010
| IP: Logged |
UBBFriend: Email this page to someone!
Printer-friendly view of this topic