Question on DNA and Cohenim #dna


Although my name is Kaplan, I was told by my older brother that we are not Cohenim. My Y-chromosome dna testing showed that I belong to Haplogroup G (M201). How can I find out which group I belong to?
Leonard Kaplan

Stephen Weinstein

There is no way to conclusively prove through DNA that someone is a Cohen.  The child of a non-Jewish woman is never a Cohen, even if he properly converts to Judaism and his father was a Cohen.  However, his Y-chromosome (and that of his son) would still be the same as that of his father, who was a Cohen.  To be a Cohen, you need a line going back to the time of the Exodus in which everyone was born to someone whose mother was Jewish when he was born.  DNA testing will never tell you whether a woman converted before her son was born (which would make him a Cohen if he father was Cohen, and make his son a Cohen, if that son's mother was Jewish) or after her son was born (which would make her son, and therefore his son, not Cohenim).

Stephen Weinstein

I have been reminded that my previous answer was wrong because I neglected to consider the restrictions on whom a Kohen can marry.

First, that means that even if a Kohen and a Jewish woman have a son, the son won't necessarily be a Kohen under certain circumstances, but Y-DNA testing won't indicate that the child isn't a Kohen.

Second, if a Kohen and the daughter of a convert (I've changed this from a Kohen and a convert) have a son, he's a Kohen (and so is his son, if born Jewish), but if a Kohen and a gentile do, the child is not (even if he converts) and neither is his son (even if born Jewish).  DNA testing can't tell the difference because conversion doesn't change a person's DNA.

So while I got some of the details wrong, my point is still valid: DNA can't prove that someone is a Kohen.

Adam Cherson

Dear Leonard,

In 2004 some geneticists wrote a paper in which they described Cohanic haplogroups. According to this work, the most prevalent haplogroup tree among Sephardic and Ashkenazic Cohanm is the J-P58 tree (31.8% and 51.6%, respectively). The next highest rates were 27.9% in the J-M172 tree and then 5.6% in the R-M269 tree. The G-M201 group represents about 3-4% of the Cohanim sampled in the study. There were about seven other haplogroups reported as having Cohanic members.

According to Biblical history, only the direct male heirs of Aharon the Priest are Cohanim (here is an article about the current state of y-chromosome research: As you know, not every generation in every place produces male heirs and hence the emergence of other chromosomal Cohanic lines, as needed.

Adam Cherson


DOI 10.1007/s00439-009-0727-5

Jill Whitehead

If you are G haplogroup (your direct male line) you would be either a sub clade of G1 or G2. My brother is M377 which is G2b. They are not Cohenim. No-one in the G haplogroups have been found to be Cohnim. You may be related to Cohenim though a non- direct branch (e.g.mother's father's side or father's mother's father's side) but your direct line could not be Cohenim if you are from a G haplogroup.

Jill Whitehead, Surrey, UK

Jeffrey Herrmann

Once upon a time (2012), when life was simpler, I was informed that my Y-DNA showed I belonged to haplogroup J-P58, where J was a major haplogroup and P58 was my  terminal SNP identified by testing as of that time.  I felt then that all my fellow P58 males were my kin somehow.  Since then FTDNA has made enormous strides in slicing and dicing the branches of the Y-chromosome haplotree through its Big Y 500 and later its Big Y 700 tests.  Currently I am located in J-M304 => J-M267 => J-CTS12238 => J-Z2217 => J-L620 => J-PF483 => J-L136 => J-P58 => J-CTS9721 => J-S4924 => J-L818 => J-L816 => J-ZS2728 => J-ZS12186 => J-ZS12183 => J-ZS12187.   There I sit, alone on my own twig of the haplotree.  I confess I do find the science fascinating, but it has not enabled me to find a single Y-DNA relative.

Adam Cherson

@Jeffrey Herrmann,

I had to giggle a little when I read your note because I have also undergone that journey ;-)
One thing is for certain: what we think we know today won't be the same as what we think we know tomorrow!
Most likely there are numerous persons on your twig, they just haven't taken the plunge into DNA testing. You are a pioneer into your sub-tree, which surely contains fabulous undiscovered mysteries.
Hopefully those mysteries will be made clear during our lifetimes.

@Jill Whitehead, Please see my next comment. If the Hammer report is correct, then there are some G persons who come from a Cohanic tradition.

@Stephen Weinstein: You raise some interesting points. For purposes of clarity I usually refer to Cohanim  and y-chromosome Aharons as being two distinct categories. Your explanation makes clear that not all y-chromosome Aharons are Cohanim, strictly speaking under Halakhic law. But one needs to be careful here because strictly speaking under Halakhic law, there can be no non-y-chromosome Aharons who are Cohanim, and yet there are apparently many R-M269 Cohanim (according to the Hammer report). I believe there has to be a Rabbinical interpretation of the definition of Cohanim to include also persons who by tradition have become Cohanim, but do not express Aharon's y-chromosome. The purpose of all of this is not to exclude some Cohanim who are not descended from y-chromosome Aharon from the priesthood but to explain and accept how the necessities of how random human reproduction sometimes require cultural adjustment to our ways of thinking.

What I find fascinating about today's discussion landscape is that it is becoming evident that certain parts of the Old Testament are more than postdictional metaphor; certain parts seem to be revealing actual geneaological and social facts which can be merged with DNA, linguistic, and archaeological evidence to build a fuller picture of human history and Jewish history.

Kudos to you and to everyone working in this field!

Have a Splendid Day,