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Cape Verde Jewish roots? #dna #sephardic


David S STERN
 

Hello,

My son's partner is from Cape Verde.  She believes that her family has Jewish ancestors, and the presence of Jews in Cape Verde is well documented.  My questions is whether DNA tests could help her determine this.  My own family is Askenazi, and the DNA results from Ancestry are sound, but I don't know anything about the results for Sephardi Jewish roots.  Any advice would be welcome.

Many thanks.

David Stern


michael.greenfield@...
 

Hello David,

DNA results work as well as they do for Ashkenazim because this group appears to have
passed through a genetic bottleneck at its founding, approx. 1100 years ago, probably
somewhere in northeast France.  That is, Ashkenazim bear an unmistakable genetic
signature.  Similar events are not well identified in the general Sephardic population, and I
suspect that DNA would not be helpful.  An exception would be kohen or levite ancestry and
markers in the y chromosome, but these would have had to be maintained through an unbroken
male lineage over 5 centuries.  Somewhat unlikely.  If written history, e.g. baptismal certificates, is
available, that might be a lead, particularly if one could establish a link to known
converso families (16th century).  Unlike Ashkenazim, Sephardim had family names extending
back many, many centuries.      Michael Greenfield       Tours, FR


Dan Nussbaum
 

You definitely should try DNA testing. One never knows what would show up.

I dwelled for a decade in New Bedford, Massachusetts which has a large Cape Verdean population. There were women among them who still lit candles on Friday night.

Daniel Nussbaum II, M.D., FAAP
Retired Developmental Pediatrician
Rochester, New York
yekkey@...
 


Dan Nussbaum
 

An addendum to my previous statement. Try to get DNA from both sexes. Often a Y chromosome can tell a good deal.

Daniel Nussbaum II, M.D., FAAP
Rochester, New York
yekkey@...
 


David S STERN
 

Thanks, Dan.  I understand that Cape Verdeans have a practice of placing stones on a gravestone when visiting a cemetery, no doubt an influence from Jews who settled in Cape Verde.

Best,

David Stern


Kevin Brook
 

DNA ethnicity estimates are not the only, or the most accurate, way to determine this answer because they can give false positives as well as false negatives. MyHeritage DNA's and Family Tree DNA's Sephardic Jewish categories are not foolproof, particularly the former.

It's more significant to find autosomal DNA cousin matches who are Jewish (either Sephardic or Ashkenazic), but don't automatically trust that those matches are real because short segments need verification. Extensive rounds of triangulation among 6 or more matches and two-sided parent-child phasing using GEDmatch's tools helps to distinguish real matches from identical-by-chance matches. Merely matching one or two Jews randomly isn't enough; you would have to establish a pattern where a cluster of them match on the same chromosome across the same start and end positions and that they also match each other in the same location. I also recommend ignoring matches that fall entirely within Excess IBD Regions because those are notorious for false matches.

Y-chromosomal testing is far less likely to yield Jewish matches for the average descendant of Sephardic Conversos, compared to autosomal DNA tests.

I have not yet seen a Cape Verdean match to a Sephardic DNA segment but indications are that it would be possible based on what we know about the island's migrational history. I have confirmed the existence of Sephardic DNA segments in mainland Portuguese Catholics, Azorean Portuguese (from the Azores Islands), and Brazilian Catholics.

Kevin Alan Brook