DNA Evidence

Finegrained DNA research in the near future might very well contradict some of the findings i have presented earlier. For whatever reason it may turn out that some ethnic groups passed on their genetic legacy disproportionate to their estimated share of population or to their cultural, linguistical significance. Then again it might also confirm some of the findings in greater detail. I won’t name all the possible objections you could have about presentday BGA (biogeographical analysis) & DNA testing. It’s obvious it’s far from 100% accurate yet and perhaps it may never really be because of inherent contradictions. Still it can already be used to gather some indicative (not conclusive) data.

I will just show some mtDNA studies as well the autosomal DNA results of Cape Verdeans on 23andme. It’s only a very sketchy outlook but on a whole it does seem to be in line with what I discussed earlier.

To start off this very early pioneering effort (1957!!!) to find traces of specific ethnic/regional African origins within Cape Verdeans bloodgroups! It was used by the oftquoted Cape Verdean historian Antonio Carreira to claim that the Wolof, Mandinga and Fula would be among the main ethnic elements for Cape Verdeans. However he already acknowledged himself that there was a severe lack of samples, something that hasn’t changed till this day.

Em 1957, Almerindo Lessa e Jacques Ruffié publicaram, em edição da Junta de Investigações do Ultramar, um volume contendo dois trabalhos, intitulados Seroantropologia das Ilhas de Cabo Verde e Mesa Redonda sobre o Homem Cabo- Verdiano.

 

A. Carreira - Bloodgroups

 

 

 

Maternal Haplogroup Analysis

There’s been two studies on Cape Verdean maternal haplogroups i know of which concluded they were as a whole reflective of Senegambian/Guinea and even in part of Mauretania. Uniparental analysis is of course less predictive of ancestral composition than autosomal analysis which considers the entire DNA and not just direct parental lineages. But still given the inherent limitations very interesting outcomes.

Dissecting the Within-Africa Ancestry of Populations of African Descent in the Americas

link

Our admixture analysis indicated that the current population of Cabo Verde derives solely from West Africa (~100% from W/WC, not including Bantu speakers or Pygmy), namely from West Niger-Congo speakers of Guinea-Bissau, Senegal, and Sierra Leone (~90%) and Semitic/Berber speakers of Mauritania, Mali and Western Sahara (~10%).

This study basically compares the Cape Verdean mtDNA variation with an extensive database consisting of 5800 individuals from 143 African populations. In the first chart 41% of Cape Verdean maternal haplo’s are being shown as most similar to Wolof/Lebou and 59% similar to mtDNA variation in Guiné Bissau and Mali. Of course this shouldn’t be mutually exclusive ancestrally speaking. Also interesting to see the relatively high Berber/Mauretania similarity being mentioned. This corroborates the minor North African %’s scored by Cape Verdeans who got tested by the personal DNA testing company 23andme (i will expand on this later on). This North African affinity could signal either direct ancestry from Berber/Morisco’s/Guanche but also indirectly via Fula. Eventhough in this particular study no similarity was found with Fula mtDNA variation, but that’s perhaps because their Fula samples are not from Upper Guinea but from Cameroon/Niger/Burkina Faso.

The relative contribution of African regions B

The relative contribution of African regions A

 

 

 

 

Mitochondrial portrait of the Cabo Verde archipelago: the Senegambian outpost of Atlantic slave trade

link

summary
In order to study the matrilineal genetic composition in Cabo Verde (Republic of Cape Verde), an archipelago that used to serve as a Portuguese entrepot of the Atlantic slave trade, we have analysed a total of 292 mtDNAs sampled from the seven inhabitated islands for the hypervariable segment I (HVS-I) and some characteristic RFLPs of the coding regions. The different settlement history of the northwestern group of the islands is well reflected in the mtDNA pool. The total Cabo Verde sample clearly displays the characteristic mitochondrial features of the Atlantic fringe of western Africa and testies to almost no mitochondrial input from the Portuguese colonizers.

 

Basically this study is saying that Cape Verde’s mtDNA profile fits best with the mtDNA variation as found in Senegambia.

Figure 2 displays the resulting twodimensional
PC plot. The first component reflects
a clear NW-SE cline, where NW Cabo Verde is
paired with Senegal (Mandenka), SE Cabo Verde
with Senegal (mixed)
, the Dominican Republic
with Niger}Nigeria, and Brazil with Mozambique.
This gives some hints at the ancestry of
the populations that were ultimately created by
slave trade.

Senegmabian outpost fig.2

Interesting quote about the northwestern Cape Verdean islands (Barlavento) having a subset of variety as found in Santiago/Fogo. (“SE Cabo Verde”) Also intriguing the mentioning of possibly Mandenka fugitive slaves populating Santo Antão. Surely there must have been other ethnicities involved as well though. Too bad they provide no reference/footnote for it.

 
The differences in haplotype frequencies (as
well as some haplogroup frequencies) between
SE Cabo Verde and NW Cabo Verde are striking,
but parallel the significant serological differences
found between Santiago and Santo Antao/Sao
Vicente (Lessa & Ruffie!, 1960). Nevertheless, the
major haplotypes in both regions are nearly the
same, and no haplogroups were found in the NW
group that were not already sampled in the SE
group of islands. On the other hand, the former
islands seem to be missing three minor haplogroups
of the latter islands. The evident reduction
in NW diversity indicates rather strong
founder effects. This agrees with the historical
records, stating that fugitive slaves from the
more populated islands (e.g. Santiago) escaped to
the NW islands. These escapees may have formed
whole clans (organized according to the place of
origin of their ancestors), thus having enforced
drift effects. It is tempting to infer from the
haplogroup profilles that a considerable number
of those escapees had their maternal ancestry in
the Mandenka.
It is plausible that all the NW
major haplotypes were already involved in the
pioneer settlement of Santo Antão. As to the
mtDNAs observed, São Vicente is almost indistinguishable
from the earlier settled Santo Antao. Bottlenecks in the
course of the famines(in the 19th century and even later)
may have had a stronger effect in the NWpool compared to
the SE pool. The haplotypes found in just one ethnic group
(Mandenka) of Senegal do not show very similar
frequencies to those found in Cabo Verde. Clearly
a better and more thorough mtDNA survey of
mainland West Africa is needed to understand
fully the haplotype composition of Cabo Verde.

 

 

Autosomal testing

The Admixture Structure and Genetic Variation of the Archipelago of Cape Verde and Its Implications for Admixture Mapping Studies

Link

Again some differentiation is being picked up between the northern (Barlavento) and southern (Sotavento) islands. Because of genetic drift and smaller founding populations in the Barlavento (Santo Antão & São Nicolau) and a bigger impact of continued lowlevel slave imports during the 1700’s/1800’s in Sotavento (Fogo & Santiago) it may be assumed that the diversity of African origins in Barlavento is largely a subset of the greater diversity found in Sotavento. On the other hand it may also be that some lineages/ancestries could be unique to either Barlavento or Sotavento because they were introduced by atypical North European slavetrading in the 1700’s. I’ve seen some historical references being made to English/French ships selling slaves in Cape Verde (illegally) from Senegambia, but also further away (Benin and even Congo). The numbers involved must have been small though because Cape Verdean slaveowning elites were very much impoverished at that time and production in the slavelabour sectors was decreasing if anything.

Some thoughtprovoking quotes from the paper

 Taking into consideration the historical data [14], these patterns
could be interpreted in two ways. According to one hypothesis,
a substantial part of the North-to-South genetic differentiation can
be attributed to demographic events (admixture, drift and founder
effects) ensuing the initial settlement of Santiago and Fogo, without
further significant exogenous contributions besides the regular
importation of slaves to the two southern islands. Alternatively, the
North and South genetic clusters could result from separate
migrations coming from Europe (mainly Portugal) and the West
Coast of Africa, which then evolved in parallel before converging
into a common cultural and social background.
Consistent with the first hypothesis, we found that Santiago is
the most genetically diverse island of the archipelago (Figure 5),
and played particularly important role in the settling of Fogo
(Table 3), where evidence for founder effects is especially striking
(Figure 5). However, the two peopling hypotheses are not mutually
exclusive and we also find a significant genetic component that is
exclusive to each island.
All these results, together with the admixture analysis, are
concordant in indicating that the most likely scenario for the
colonization of the Cape Verde archipelago may lie in between the
two stated hypotheses, suggesting that the various groups of islands
have a shared genetic history that results from a common origin in
Santiago, followed by differentiation through genetic drift and
subsequent input of independent external migrations
.

 

 

 

23andme DNA Cousin matches for Cape Verdeans

Because generally speaking African origins for Cape Verdeans might date back 300-500 years, it’s to be expected they will mostly share smaller segments with mainland Africans. The database of 23andme is consisting of it’s mostly USA-based customers and therefore very limited still for Africans. Although I think it might already have about 10 Upper Guineans (Senegalese, Gambians, Guineans). From the over 20 Cape Verdeans i’m sharing with myself on 23andme these are their African DNA matches/”cousins” sofar. Basically it’s detecting shared DNA segments which might be indicative of shared ancestry.

Guiné Bissau

This is the biggest match, the Guinean person being a Mandinga (i’m also sharing with him) and the Cape Verdean he’s matching being from Fogo. Perhaps a connection to relatively late Mandinga presence in Cape Verde (1700’s/1800’s)?

GB CoA

Senegal,

Seems to be the same DNA segment on chromosome 3 for 2 Cape Verdean persons who are only distant DNA cousins, not recently related. So perhaps this might be some ancient segment (1500’s) circulating/being recycled in the Cape Verdean genepool?

Senegal2 CoA

 

Senegal CoA

Gambia

Gambia CoA

 

 

 

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