Ketuvot 23b ~ The Cohen Gene

HEllo, I'm Your New Cohen

משנה כתובות דף כג עמוד ב 

וכן שני אנשים, זה אומר כהן אני וזה אומר כהן אני - אינן נאמנין, ובזמן שהן מעידין זה את זה - הרי אלו נאמנין; רבי יהודה אומר: אין מעלין לכהונה על פי עד אחד

Likewise in the case of two men; one says, "I am a Cohen", and the other says "I am a Cohen", they are not believed. If however they testify about one another they are believed. R. Yehuda said: we do not elevate [a person] to the status of Cohen based on the testimony of only one witness....

Being a Cohen comes with rights and duties. They get called to the Torah first, and are given preference to lead Birkat Hamazon.  During Temple times, they got lots and lots of food.  But how do you prove you are a Cohen, and entitled to these privileges?  According to the Mishnah in today's Daf Yomi, (and discussed in detail in the talmudic discussion that follows,) you need witnesses to attest to your status. But what if the Cohen was mistaken about his ancestors? What if the witnesses were being paid to dupe the locals into believing the Cohen was legitimate? Is there an alternative to the methods mentioned in this Mishnah? Perhaps.

The Saturday Night Live Cohen 

My friend Misha Galperin, (the former CEO of the Jewish Federation of Greater Washington and  CEO of International Development at The Jewish Agency) is a Cohen. Only he didn't know it when he arrived in America from the Soviet Union.  Here's what happened, as told to me in a recent email  that he kindly allowed me to share:

Five months after arriving in the US, I am sitting in the lounge of Yeshiva University's dorm watching SNL with my tutor who was teaching me Alef Bet is so I can start classes on Monday.
A skit starts with guest host Leonard Nimoy dressed as Mr. Spock - with ears - and at the end he raises his right palm in the symbolic gesture and says: "Live long and prosper!"
I turn to the tutor and ask him what this gesture means. Why?--he asks. "Because my father taught me this, and his father taught it to him before being murdered by Nazis in 1941. My father did not know what it meant, but he taught me..."

And so Misha learned that he was a Cohen from Saturday Night Live. But not all Cohanim are so lucky. (Fun fact: Leonard Nimoy ז’ל wrote about his decision to give Mr. Spock this priestly hand salute in his 1997 autobiography I Am Not Spock.)  With neither witnesses nor TV to help, is there another way to establish one's genealogy as a member of the priestly class? That's where the Cohen Gene comes in.  

The Cohen Gene

If all Cohanim are descended from Aaron, and the privilege is only transmitted from father to son, then perhaps being a Cohen can be genetically linked to a chromosome that is only passed from father to son. And there is such a chromosome. It's the Y chromosome, and all (fertile) men carry a copy that comes only from their biological father. (Quick recap: girls are XX and boys are XY. So all girls carry one X chromosome from mum and one X chromosome from dad. Boys, on the other hand, only get their X chromosome from mum, and their Y chromosome from dad. This can lead to other problems like hemophilia, which we've talked about elsewhere.) That's exactly what prompted  Karl Skorecki from the Technion, and colleagues from University College London, to analyze the Y chromosome in Cohanim and compare it to the rest of the Jewish population.  In 1997 they published a paper in Nature that looked at a special bit of the Y chromosome called YAP. Actually, they looked at 6 kinds of the YAP haplotype, (a haplotype being what geneticists call bunches of DNA sequences), and compared their frequency in Cohanim and non-Cohanim.    

Skorecki K, et al. Y Chromosomes of Jewish Priests. Nature 1997. 385:32.

As you can see highlighted, the YAP+ haplotype was found in only 1.5% of those who self-identified as Cohanim, but in over 18% of non-Cohanim.  The different frequency was found in both Ashkenazi and Sephardi Cohanim,  a result that the authors claimed was "consistent with an origin for the Jewish priesthood antedating the division of world Jewry into Ashkenazic and Sephardic communities."

“These Y-chromosome haplotype differences confirm a distinct paternal geneology for Jewish priests.”

— Skorecki et al. Nature 1997. 385: 32.

David Goldstein, who now directs a genetics lab at Columbia University, also published a study on the Y-chromosome of Cohanim, using a sample that included the DNA swabbed "from the mouths of sunbathers on the beaches of Tel Aviv." Here is what Goldstein concluded:

Despite the high levels of variation, we could see a clear difference between Cohen and Israelite chromosomes. The most common chromosomes observed in the Israelites (that is, non-Cohen and non-Levite Jews) were found in only 12% of the Israelite individuals sampled. By contrast, more that half of the Cohen Y chromosomes were identical at the sites considered - that is, the majority of the self-identified Cohanim had the same type of Y chromosome. Even more remarkable, this same type of Y was found at high frequencies in both Ashkenazi (45%) and Sephardi (56%) Cohanim. (Goldstein, p.31)

Goldstein named this chromosome type the Cohen Modal Haplotype, and claimed that it showed "definitively" that Cohen status was not adopted (i.e. made up by some, eager for the benefits) but inherited.  And now things started to get really interesting. 

Dating the Original Aaron

So all, (OK, not all, but certainly most) of the approximately 500,000 Cohanim alive today seem to have originated from a common ancestor - a primordial Cohen. And just when did he live? Well, by analyzing small differences in the Cohen Modal Haplotype, and assuming that a generation time is 25 years, Goldstein et al. stated (with a confidence interval of 95%) that the origin of the priestly Y chromosome was "sometime during or shortly before the Temple period in Jewish history."

Not So Fast...

OK, a couple of things need to be noted here, before anyone claims that "genetics proves the Bible." First- as Goldstein himself notes in his book, his numbers may be off, by quite a bit:

Permit me here, after what was for me the first - and still one of the few - real thrills of discovery that punctuate the tedium and detail of science, the necessary reality check. Our results appeared to be a striking confirmation of the oral tradition. It even led to repeated claims in the press that my colleagues and I "found Aaron's Y chromosome." But although three thousand years is our best guess [as to when Primordial Cohen may have lived] the range of possible dates was and is very broad. Given our uncertainty about the ways mutations happen and how fast, we may be off by several hundred years or more in either direction. (Goldstein p.38).

Second, some later work done by Skorecki (he of the Technion 1997 Nature paper) suggests that the class of Cohanim may have had more than one common ancestor.  This work posits that there was not one primordial Cohen, but a few clans of Cohanim, from whom all later Cohanim are descended. (Or more technically stated:"...lineages characterized by the 6 Y-STRs used to define the original Cohen Modal Haplotype are associated with two divergent sub-clades...and thus cannot be assumed to represent a single recently expanding paternal lineage.")

And finally, work from Brigham Young University (and boy, those guys are really into ancestry) reminds anyone looking to do a quick Cohen DNA test to be careful.

The Cohen Modal Haplotype is observed in high frequency within the Cohanim, but also presents with significant incidence in other non-Jewish populations. The occurrence of the CMH in deeply divergent SNP haplogroups also indicates a lack of specificity of the CMH to the ancient Hebrew population. As such, inference of relation to Jewish populations for individuals or groups should be performed with caution when using the original CMH definition, as a false-positive result is likely.

 "A false positive is likely" - in other words, the test may show you are a Cohen, but really...you aren't. 

Genetic Testing - It's Not Just for Cohanim

And now that a Cohen "Gene" may have been identified, what about the rest of us non-Cohanim? Some have used genetic testing to discover a forgotten heritage or find long-lost cousins.  One rather keen family member of Polonsky rabbinic lineage (claiming in passing to be descended from King David, the Kalonymos family, and Rashi) used the presence of a "relatively rare R-M124 haplotype" on the Y chromosome to confirm a common ancestor and find a new marker that represents "Polonsky rabbinic lineage." (I confess I am jealous. My grandfather drove a black London taxi, and last time I checked, Rashi was not one of my known ancestors.) 

It's Not About Your Ancestors, It's About You

רמב"ם הלכות שמיטה ויובל פרק יג הלכות יב –יג 

ולמה לא זכה לוי בנחלת ארץ ישראל ובביזתה עם אחיו? מפני שהובדל לעבוד את יי לשרתו ולהורות דרכיו הישרים ומשפטיו הצדיקים לרבים שנאמר יורו משפטיך ליעקב ותורתך לישראל, לפיכך הובדלו מדרכי העולם לא עורכין מלחמה כשאר ישראל ולא נוחלין ולא זוכין לעצמן בכח גופן, אלא הם חיל השם שנאמר ברך יי חילו, והוא ברוך הוא זוכה להם, שנאמר: אני חלקך ונחלתך

ולא שבט לוי בלבד אלא כל איש ואיש מכל באי העולם אשר נדבה רוחו אותו והבינו מדע להבדל לעמוד לפני יי לשרתו ולעובדו לדעה את יי והלך ישר כמו שעשהו האלהים ופרק מעל צוארו עול החשבונות הרבים אשר בקשו בני האדם הרי זה נתקדש קדש קדשים. ויהיה יי חלקו ונחלתו לעולם ולעולמי עולמים ויזכה לו בעה"ז דבר המספיק לו כמו שזכה לכהנים ללוים, הרי דוד עליו השלום אומר: יי מנת חלקי וכוסי אתה תומיך גורלי

Why did the Levi'im not receive a portion in the inheritance in Israel and in the spoils of war like their brethren? Because they were set aside to serve God, to minister to Him and to instruct the masses about His just paths and righteous judgments... Therefore they were set apart from the mundane matters of the world. They do not wage war like the remainder of the Jewish people, nor do they receive an inheritance, nor do they acquire for themselves through their physical power. Instead, they are God's legion...and He provides for them...

Not only the tribe of Levi, but any human whose spirit moves him and who understands with his wisdom to set himself aside and stand before God - to serve Him and minister to Him and to know Him, proceeding justly as God made him, removing from his neck the yoke of the many mundane things which people seek - that person is sanctified like the Holy of Holies [in the Temple]. God will be his portion and heritage forever and will provide what is sufficient for him in this world, just as He provides for the Cohanim and the Levi'im...

Maimonides, in his Mishnah Torah,  reminds us about what is really important. It's not bringing a witness into town and telling everyone who your ancestors are. And it's not getting a DNA test to prove your stock. It's about searching for religious meaning in a world of materialism.  And that search is open to anyone, woman or man, Jew or not, Cohen, Levi, or even a plain old Yisrael.  

Shekalim 13a-b ~ The Cohen and his Stomach Problems

On page 13 of Shekalim we read about the fifteen Temple officers and the administrators who held them:

שקלים טו, א

…אֵילּוּ הֵן הַמְמוּנִּין שֶׁהָיוּ בַּמִּקְדָּשׁ. יוֹחָנָן בֶּן פִּינְחָס עַל הַחוֹתָמוֹת. אֲחִייָה עַל הַנְּסָכִים. מַתְיָה בֶּן שְׁמוּאֵל עַל הַפְּייָסוֹת…בֶּן אֲחִייָה עַל חוֹלֵי מֵעַיִם

These are the officials who served in specific positions in the Temple: Yochanan ben Pinchas was responsible for the seals. Achiyya was responsible for the libations, while Ben Achiyya was responsible for the treatment of those Cohanim who had an intestinal disorder…

The Talmud then explains the nature of these intestinal disorders:

שקלים טו, ב

בֶּן אֲחִייָה עַל חוֹלֵי מֵעַיִם. עַל יְדֵי שֶׁהָיוּ הַכֹּהֲנִים מְהַלְּכִין יְחֵיפִים עַל הָרִצְפָּה וְהָיוּ אוֹכְלִין בָּשָׂר וְשׁוֹתִין מַיִם הָיוּ בָאִין לִידֵי חוֹלֵי מֵיעַיִם. וַהֲוָה יְדַע אֲהֵײ דֵין חֲמַר טַב לִמְעַייָא. וְהֵיי דֵין חֲמַר סְמַס לִמְעַייָא

Clostridial diarrheal infections. Meat dishes left to cool at room temperature grow large numbers of clostridia. When contaminated meat is ingested, C. perfringens types A and C produce alpha-enterotoxin in the small intestine during sporulation, causing abdominal pain and diarrhea. Type C also produces beta-enterotoxin botulism. From Harwood-Nuss’ Clinical Practice of Emergency Medicine. Kluwer 2021. Chap 115.

Ben Achiyya was appointed to treat those priests who suffered from intestinal disease: Since the priests would walk barefoot on the floor [even when it was cold, as their feet had to be in contact with the stones of the Temple floor,] and since they would eat a lot of meat from the offerings and drink a lot of water, they would contract intestinal disease. And Ben Achiyya knew that which particular type of wine was good for healing the intestines, and which type of wine was would be bad for the bowels.

Pity the Poor Cohen

It would seem then, that an upset stomach was one of the perils of the job for a Cohen called to service in the Temple. Elsewhere we have noted that the tribe of the Cohanim (pl. of Cohen) were likely to suffer from a number of different ailments including vertical diplopia (most commonly caused by damage to the fourth cranial nerve, called the trochlear nerve), nystagmus, liver disease (with gynecomastia, ascites and testicular atrophy) and depression. Some also had syndactyly, a condition in which some of the fingers or toes are fused together. That condition is genetic, but some of the other Cohen associated ailments can be explained by chronic alcohol misuse.

The causes of Gastroenteritis

It would seem that when they came to Jerusalem to serve, the Cohanim would often contract gastroenteritis, an inflammation of the gastrointestinal tract. It is a common set of conditions, and I must have treated many hundreds of people with the condition over my decades as an emergency physician (though even when working in Jerusalem, I never once made the association with the Temple service, nor asked if the patient has the risk factor of being a Cohen. Woops). The patient feels weak, and there is vomiting and loose or watery diarrhea. If the patient does not (or cannot) drink enough fluids, she can become dehydrated, and feel dizzy. In most cases the condition is self-limiting, and lasts only a day or so.

There are dozens and dozens of causes of gastroenteritis, most of which are viral. Sometimes the infectious agent produces a toxin on foods which is then ingested. In other cases the toxin is produced once the virus or bacteria have been ingested, though it doesn’t make much difference to the patient in the ER. Or the Cohen in the Temple.

Mechanisms of infectious diarrhea illness. Note that pathogens can produce an enterotoxin in food prior to ingestion. That is what gives you food poisoning. They can also produce a toxin in the intestines after ingestion, which can cause a non-bloody diarrhea (e.g., V. cholerae) or bloody diarrhea (e.g., C. difficile). From From Harwood-Nuss’ Clinical Practice of Emergency Medicine. Kluwer 2021. Chap 115.

And here, for your delight is a list of some of the agents that cause gastroenteritis, and which Ben Achiyya would have had to treat. With wine.

F=Fever, AP= Abdominal Pain, NV=Nausea and vomiting, BD= Blood diarhhea. From From Harwood-Nuss’ Clinical Practice of Emergency Medicine. Kluwer 2021. Chap 159.

Walking Barefoot, Eating meat and Gastroenteritis

In today’s page of Talmud, the upset stomachs suffered by the Cohanim is blamed on three things: walking barefoot, eating meat and drinking water. Let’s take a look and figure out if what, culpability if any, each of these had.

1. Walking Barefoot - מְהַלְּכִין יְחֵיפִים עַל הָרִצְפָּה

   Can walking barefoot lead to gastroenteritis? No. So that is easy.

2. Eating Meat - אוֹכְלִין בָּשָׂר

   Is there a relationship between eating meat and gastroenteritis? Why yes, certainly there is. In the table above you can see that a bacteria called Yersinia is a common etiological agent. Among its favorite hiding places are raw and undercooked meat, especially if that meat was contaminated with urine or feces. According to the CDC, “Y. enterocolitica causes almost 117,000 illnesses, 640 hospitalizations, and 35 deaths in the United States every year. Children are infected more often than adults, and the infection is more common in the winter.” Another bacteria that can cause a meat related enteritis is salmonella (though it is more commonly associated with eggs and poultry). As the World Health Organization likes to remind us:

   Salmonella bacteria are widely distributed in domestic and wild animals. They are prevalent in food animals such as poultry, pigs, and cattle; and in pets, including cats, dogs, birds, and reptiles such as turtles. Salmonella can pass through the entire food chain from animal feed, primary production, and all the way to households or food-service establishments and institutions.

3. Drinking Water - וְשׁוֹתִין מַיִם

   Contaminated drinking water is a well-established and still very prevalent cause of acute gastroenteritis. In a review of the problem published in Water and Health, the authors note that “transmission by food or water has been documented for astroviruses, caliciviruses, rotaviruses, and norovirus…Conservative estimates put diarrhea in the top five causes of deaths worldwide with 3.5 to 5 million deaths every year and most occurring in young children in non-industrialized countries. According to the World Health Organization (WHO), diarrheal diseases account for 4.1 % of the total DALY global burden of disease of which 88% is attributable to unsafe water supply, sanitation, and hygiene.”

   In tractate Yoma (19a) we learn that all of the water in the Temple came from but a single well, known as the בור הגולה – “The Well of the Diaspora.” That was a dangerous practice since should it become contaminated, everyone who drank from it could become sick. It would have been better (from a public health perspective) for some of those who served in the Temple to have used a second water source.

   Here are just some of the the nasty pathogens that can contaminate the water supply.

From Griffiths, J. Waterborne Diseases. In The International Encyclopedia of Public Health, 2nd edition, Volume 7, 395.

The Prohibition against eating Sacrificial Meat left out for too long

It is interesting to note that there is a biblical prohibition called Nossar (נותר) against eating sacrificial meat outside of its proscribed time. The Torah outlines the prohibitions in several places. Here are some of them:

The Paschal Lamb (Ex. 12.10):

וְלֹא־תוֹתִ֥ירוּ מִמֶּ֖נּוּ עַד־בֹּ֑קֶר וְהַנֹּתָ֥ר מִמֶּ֛נּוּ עַד־בֹּ֖קֶר בָּאֵ֥שׁ תִּשְׂרֹֽפוּ׃

You shall not leave any of it over until morning; if any of it is left until morning, you shall burn it.

The Festival Offering (Deut. 16:4)

וְלֹא־יָלִ֣ין מִן־הַבָּשָׂ֗ר אֲשֶׁ֨ר תִּזְבַּ֥ח בָּעֶ֛רֶב בַּיּ֥וֹם הָרִאשׁ֖וֹן לַבֹּֽקֶר׃

For seven days no leaven shall be found with you in all your territory, and none of the flesh of what you slaughter on the evening of the first day shall be left until morning.

The Thanksgiving Offering (Lev. 22:30)

בַּיּ֤וֹם הַהוּא֙ יֵאָכֵ֔ל לֹֽא־תוֹתִ֥ירוּ מִמֶּ֖נּוּ עַד־בֹּ֑קֶר אֲנִ֖י ה׳׃

It shall be eaten on the same day; you shall not leave any of it until morning: I am the LORD.

The Shelamim Offering (Lev. 7:15)

וּבְשַׂ֗ר זֶ֚בַח תּוֹדַ֣ת שְׁלָמָ֔יו בְּי֥וֹם קָרְבָּנ֖וֹ יֵאָכֵ֑ל לֹֽא־יַנִּ֥יחַ מִמֶּ֖נּוּ עַד־בֹּֽקֶר׃

And the flesh of his thanksgiving sacrifice of well-being shall be eaten on the day that it is offered; none of it shall be set aside until morning.

Meat that is properly roasted is less likely to contain pathogens or toxins that cause gastroenteritis. But in a Middle-Eastern climate and without refrigeration, that meat would very quickly spoil and become contaminated with all sorts of pathogens. From the perspective of good food hygiene, disposing of it within a few hours of cooking was an extremely important measure to prevent the kinds of illnesses the Cohanim seemed to catch all too often. And the while the wine that Ben Achiyya could not cure any gastroenteritis, at least its alcohol content meant that it was itself not likely to contain the pathogens found in natural water supplies.

“From the very
beginning there has been something unhealthy about these priestly aristocracies and in the customs dominant there, which are turned away from action and are partly brooding and partly emotionally explosive, resulting in the almost inevitable bowel complaints and neurasthenia which have plagued the clergy down the ages ”

— Friedrich Neitzsche. On the Genealogy of Morality. Cambridge University Press 2007. p16.

Today, we take proper food hygiene for granted, and are fastidious about washing both our hands and our food. We expect meat and vegetables to be free of bacteria, and when there are outbreaks of food-born illnesses they often make the national news, like one did just two days ago. We take such luxuries for granted, but as today’s page of Talmud reminds us, we should not do so. For much of the world’s population, clean drinking water and plentiful safe food are still not guaranteed. Be grateful for your plenty, and be grateful that you did not need to serve as a Cohen in the Temple.

Middot 37b ~ The Lineage of the Cohen

On the very last page of the tractate Middot that deals with the architecture of the Temple in Jerusalem, we read this touching scene described in the Mishnah:

מדות לז, ב

לִשְׁכַּת הַגָּזִית, שָׁם הָיְתָה סַנְהֶדְרִי גְדוֹלָה שֶׁל יִשְׂרָאֵל יוֹשֶׁבֶת וְדָנָה אֶת הַכְּהֻנָּה, וְכֹהֵן שֶׁנִּמְצָא בוֹ פְסוּל, לוֹבֵשׁ שְׁחוֹרִים וּמִתְעַטֵּף שְׁחוֹרִים, וְיוֹצֵא וְהוֹלֵךְ לוֹ. וְשֶׁלֹּא נִמְצָא בוֹ פְסוּל, לוֹבֵשׁ לְבָנִים וּמִתְעַטֵּף לְבָנִים, נִכְנָס וּמְשַׁמֵּשׁ עִם אֶחָיו הַכֹּהֲנִים. וְיוֹם טוֹב הָיוּ עוֹשִׂים, שֶׁלֹּא נִמְצָא פְסוּל בְּזַרְעוֹ שֶׁל אַהֲרֹן הַכֹּהֵן, וְכָךְ הָיוּ אוֹמְרִים, בָּרוּךְ הַמָּקוֹם בָּרוּךְ הוּא, שֶׁלֹּא נִמְצָא פְסוּל בְּזַרְעוֹ שֶׁל אַהֲרֹן. וּבָרוּךְ הוּא, שֶׁבָּחַר בְּאַהֲרֹן וּבְבָנָיו לַעֲמֹד לְשָׁרֵת לִפְנֵי ה' בְּבֵית קָדְשֵׁי הַקֳּדָשִׁים:

In the chamber of hewn stone the great Sanhedrin of Israel used to sit and judge the priesthood. A priest in whom was found a disqualification used to put on black garments and wrap himself in black and leave the premises of the Temple. One in whom no disqualification was found used to put on white garments and wrap himself in white and go in and serve along with his brother priests. They used to make a feast because no blemish had been found in the seed of Aaron the priest, and they used to say: Blessed is the Omnipresent, blessed is He, for no blemish has been found in the seed of Aaron. Blessed is He who chose Aaron and his sons to stand to minister before the Lord in the Holy of Holies.

What was the “disqualification” about which the Mishnah speaks? It arose as a result of aspersions about the lineage of the Cohen, as Maimonides describes in his Mishnah Torah:

רמב’ם חל׳ ביאת המקדש, ו, יא

בֵּית דִּין הַגָּדוֹל הָיוּ יוֹשְׁבִין בְּלִשְׁכַּת הַגָּזִית. וְעִקַּר מַעֲשֵׂיהֶם הַתָּדִיר שֶׁהָיוּ יוֹשְׁבִין וְּדָנִין אֶת הַכְּהֻנָּה וּבוֹדְקִין הַכֹּהֲנִים בְּיוּחֲסִין וּבְמוּמִין. כָּל כֹּהֵן שֶׁנִּמְצָא פָּסוּל בְּיִחוּסוֹ לוֹבֵשׁ שְׁחוֹרִים וּמִתְעַטֵּף שְׁחוֹרִים וְיוֹצֵא מִן הָעֲזָרָה. וְכָל מִי שֶׁנִּמְצָא שָׁלֵם וְכָשֵׁר לוֹבֵשׁ לְבָנִים וְנִכְנָס וּמְשַׁמֵּשׁ עִם אֶחָיו הַכֹּהֲנִים

The Great Court sat in the Chamber of Hewn Stone. Their most important and most frequent task was to rule on the ancestry and disqualifications of the priests [who served in the Temple]. Any priest in whom there was a disqualification because of their ancestry would dress in black and wear a black headscarf and would leave the Courtyard. And a priest who was found to be of appropriate ancestry would dress in white and enter to serve with his fellow priests.

The decision would be made on the testimony of priest and those who knew of his lineage, as described in this Mishnah :

משנה כתובות דף כג עמוד ב 

וכן שני אנשים, זה אומר כהן אני וזה אומר כהן אני - אינן נאמנין, ובזמן שהן מעידין זה את זה - הרי אלו נאמנין; רבי יהודה אומר: אין מעלין לכהונה על פי עד אחד

Likewise in the case of two men; one says, "I am a Cohen", and the other says "I am a Cohen", they are not believed. If however they testify about one another they are believed. R. Yehuda said: we do not elevate [a person] to the status of Cohen based on the testimony of only one witness....

But what if the Cohen was mistaken about his ancestors? What if the witnesses were being paid to dupe the locals into believing the Cohen was legitimate? Is there an alternative to the methods mentioned in this Mishnah? In today’s world of genetic testing there just might be.

The Saturday Night Live Cohen 

My friend Misha Galperin, (the former CEO of the Jewish Federation of Greater Washington and  CEO of International Development at The Jewish Agency) is a Cohen. Only he didn't know it when he arrived in America from the Soviet Union.  Here's what happened, as told to me in a recent email that he kindly allowed me to share:

Five months after arriving in the US, I am sitting in the lounge of Yeshiva University's dorm watching SNL with my tutor who was teaching me Alef Bet is so I can start classes on Monday.
A skit starts with guest host Leonard Nimoy dressed as Mr. Spock - with ears - and at the end he raises his right palm in the symbolic gesture and says: "Live long and prosper!"
I turn to the tutor and ask him what this gesture means. Why?--he asks. "Because my father taught me this, and his father taught it to him before being murdered by Nazis in 1941. My father did not know what it meant, but he taught me..."

And so Misha learned that he was a Cohen from Saturday Night Live. But not all Cohanim are so lucky. (Fun fact: Leonard Nimoy ז’ל wrote about his decision to give Mr. Spock this priestly hand salute in his 1997 autobiography I Am Not Spock.)  With neither witnesses nor TV to help, is there another way to establish one's genealogy as a member of the priestly class? That's where the Cohen Gene comes in.  

The Cohen Gene

If all Cohanim are descended from Aaron, and the privilege is only transmitted from father to son, then perhaps being a Cohen can be genetically linked to a chromosome that is only passed from father to son. And there is such a chromosome. It's the Y chromosome, and all (fertile) men carry a copy that comes only from their biological father. (Quick recap: girls are XX and boys are XY. So all girls carry one X chromosome from mum and one X chromosome from dad. Boys, on the other hand, only get their X chromosome from mum, and their Y chromosome from dad. This can lead to other problems like hemophilia, which we've talked about elsewhere.) That's exactly what prompted  Karl Skorecki from the Technion, and colleagues from University College London, to analyze the Y chromosome in Cohanim and compare it to the rest of the Jewish population.  In 1997 they published a paper in Nature that looked at a special bit of the Y chromosome called YAP. Actually, they looked at 6 kinds of the YAP haplotype, (a haplotype being what geneticists call bunches of DNA sequences), and compared their frequency in Cohanim and non-Cohanim.    

Skorecki K, et al. Y Chromosomes of Jewish Priests. Nature 1997. 385:32.

As you can see highlighted, the YAP+ haplotype was found in only 1.5% of those who self-identified as Cohanim, but in over 18% of non-Cohanim.  The different frequency was found in both Ashkenazi and Sephardi Cohanim,  a result that the authors claimed was "consistent with an origin for the Jewish priesthood antedating the division of world Jewry into Ashkenazic and Sephardic communities."

“These Y-chromosome haplotype differences confirm a distinct paternal geneology for Jewish priests.”

— Skorecki et al. Nature 1997. 385: 32.

David Goldstein, who directs the  Center for Human Genome Variation at Duke University, also published a study on the Y-chromosome of Cohanim, using a sample that included the DNA swabbed "from the mouths of sunbathers on the beaches of Tel Aviv." Here is what Goldstein concluded:

Despite the high levels of variation, we could see a clear difference between Cohen and Israelite chromosomes. The most common chromosomes observed in the Israelites (that is, non-Cohen and non-Levite Jews) were found in only 12% of the Israelite individuals sampled. By contrast, more that half of the Cohen Y chromosomes were identical at the sites considered - that is, the majority of the self-identified Cohanim had the same type of Y chromosome. Even more remarkable, this same type of Y was found at high frequencies in both Ashkenazi (45%) and Sephardi (56%) Cohanim. (Goldstein, p.31)

Goldstein named this chromosome type the Cohen Modal Haplotype, and claimed that it showed "definitively" that Cohen status was not adopted (i.e. made up by some, eager for the benefits) but inherited.  And now things started to get really interesting. 

Dating the Original Aaron

So all, (all right, not all, but certainly most) of the approximately 500,000 Cohanim alive today seem to have originated from a common ancestor - a primordial Cohen. And just when did he live? Well, by analyzing small differences in the Cohen Modal Haplotype, and assuming that a generation time is 25 years, Goldstein et al. stated (with a confidence interval of 95%) that the origin of the priestly Y chromosome was "sometime during or shortly before the Temple period in Jewish history."

Not So Fast...

OK, a couple of things need to be noted here, before anyone claims that "genetics proves the Bible." First- as Goldstein himself notes in his book, his numbers may be off, by quite a bit:

Permit me here, after what was for me the first - and still one of the few - real thrills of discovery that punctuate the tedium and detail of science, the necessary reality check. Our results appeared to be a striking confirmation of the oral tradition. It even led to repeated claims in the press that my colleagues and I "found Aaron's Y chromosome." But although three thousand years is our best guess [as to when Primordial Cohen may have lived] the range of possible dates was and is very broad. Given our uncertainty about the ways mutations happen and how fast, we may be off by several hundred years or more in either direction. (Goldstein p.38).

Second, some later work done by Skorecki (he of the Technion 1997 Nature paper) suggests that the class of Cohanim may have had more than one common ancestor.  This work posits that there was not one primordial Cohen, but a few clans of Cohanim, from whom all later Cohanim are descended. (Or more technically stated:"...lineages characterized by the 6 Y-STRs used to define the original Cohen Modal Haplotype are associated with two divergent sub-clades...and thus cannot be assumed to represent a single recently expanding paternal lineage.")

And finally, work from Brigham Young University (and boy, those guys are really into ancestry) reminds anyone looking to do a quick Cohen DNA test to be careful.

The Cohen Modal Haplotype is observed in high frequency within the Cohanim, but also presents with significant incidence in other non-Jewish populations. The occurrence of the CMH in deeply divergent SNP haplogroups also indicates a lack of specificity of the CMH to the ancient Hebrew population. As such, inference of relation to Jewish populations for individuals or groups should be performed with caution when using the original CMH definition, as a false-positive result is likely.

 "A false positive is likely" - in other words, the test may show you are a Cohen, but really...you aren't. 

Genetic Testing - It's Not Just for Cohanim

And now that a Cohen "Gene" may have been identified, what about the rest of us non-Cohanim? Some have used genetic testing to discover a forgotten heritage or find long-lost cousins.  One rather keen family member of Polonsky rabbinic lineage (claiming in passing to be descended from King David, the Kalonymos family, and Rashi) used the presence of a "relatively rare R-M124 haplotype" on the Y chromosome to confirm a common ancestor and find a new marker that represents "Polonsky rabbinic lineage." (I confess I am jealous. My grandfather drove a black London taxi, and last time I checked, Rashi was not one of my known ancestors.) 

It's Not About Your Ancestors, It's About You

רמב"ם הלכות שמיטה ויובל פרק יג הלכות יב –יג 

ולמה לא זכה לוי בנחלת ארץ ישראל ובביזתה עם אחיו? מפני שהובדל לעבוד את יי לשרתו ולהורות דרכיו הישרים ומשפטיו הצדיקים לרבים שנאמר יורו משפטיך ליעקב ותורתך לישראל, לפיכך הובדלו מדרכי העולם לא עורכין מלחמה כשאר ישראל ולא נוחלין ולא זוכין לעצמן בכח גופן, אלא הם חיל השם שנאמר ברך יי חילו, והוא ברוך הוא זוכה להם, שנאמר: אני חלקך ונחלתך

ולא שבט לוי בלבד אלא כל איש ואיש מכל באי העולם אשר נדבה רוחו אותו והבינו מדע להבדל לעמוד לפני יי לשרתו ולעובדו לדעה את יי והלך ישר כמו שעשהו האלהים ופרק מעל צוארו עול החשבונות הרבים אשר בקשו בני האדם הרי זה נתקדש קדש קדשים. ויהיה יי חלקו ונחלתו לעולם ולעולמי עולמים ויזכה לו בעה"ז דבר המספיק לו כמו שזכה לכהנים ללוים, הרי דוד עליו השלום אומר: יי מנת חלקי וכוסי אתה תומיך גורלי

Why did the Levi'im not receive a portion in the inheritance in Israel and in the spoils of war like their brethren? Because they were set aside to serve God, to minister to Him and to instruct the masses about His just paths and righteous judgments... Therefore they were set apart from the mundane matters of the world. They do not wage war like the remainder of the Jewish people, nor do they receive an inheritance, nor do they acquire for themselves through their physical power. Instead, they are God's legion...and He provides for them...

Not only the tribe of Levi, but any human whose spirit moves him and who understands with his wisdom to set himself aside and stand before God - to serve Him and minister to Him and to know Him, proceeding justly as God made him, removing from his neck the yoke of the many mundane things which people seek - that person is sanctified like the Holy of Holies [in the Temple]. God will be his portion and heritage forever and will provide what is sufficient for him in this world, just as He provides for the Cohanim and the Levi'im...

Maimonides, in his Mishnah Torah,  reminds us about what is really important. It's not bringing a witness into town and telling everyone who your ancestors are. And it's not getting a DNA test to prove your stock. It's about searching for religious meaning in a world of materialism.  And that search is open to anyone, woman or man, Jew or not, Cohen, Levi, or even a plain old Yisrael.  

[Repost from Ketuvot 23b]

Ketuvot 23b ~ The Cohen Gene

HEllo, I'm Your New Cohen

משנה כתובות דף כג עמוד ב 

וכן שני אנשים, זה אומר כהן אני וזה אומר כהן אני - אינן נאמנין, ובזמן שהן מעידין זה את זה - הרי אלו נאמנין; רבי יהודה אומר: אין מעלין לכהונה על פי עד אחד

Likewise in the case of two men; one says, "I am a Cohen", and the other says "I am a Cohen", they are not believed. If however they testify about one another they are believed. R. Yehuda said: we do not elevate [a person] to the status of Cohen based on the testimony of only one witness....

Being a Cohen comes with rights and duties. They get called to the Torah first, and are given preference to lead Birkat Hamazon.  During Temple times, they got lots and lots of food.  But how do you prove you are a Cohen, and entitled to these privileges?  According to the Mishnah in today's Daf Yomi, (and discussed in detail in the talmudic discussion that follows,) you need witnesses to attest to your status. But what if the Cohen was mistaken about his ancestors? What if the witnesses were being paid to dupe the locals into believing the Cohen was legitimate? Is there an alternative to the methods mentioned in this Mishnah? Perhaps.

The Saturday Night Live Cohen 

My friend Misha Galperin, (formerly the CEO of the Jewish Federation of Greater Washington and  of International Development at The Jewish Agency) is a Cohen. Only he didn't know it when he arrived in America from the Soviet Union.  Here's what happened, as told to me in an email that he kindly allowed me to share:

Five months after arriving in the US, I am sitting in the lounge of Yeshiva University's dorm watching SNL with my tutor who was teaching me Alef Bet is so I can start classes on Monday.
A skit starts with guest host Leonard Nimoy dressed as Mr. Spock - with ears - and at the end he raises his right palm in the symbolic gesture and says: "Live long and prosper!"
I turn to the tutor and ask him what this gesture means. Why?--he asks. "Because my father taught me this, and his father taught it to him before being murdered by Nazis in 1941. My father did not know what it meant, but he taught me..."

And so Misha learned that he was a Cohen from Saturday Night Live. But not all Cohanim are so lucky. (Fun fact: Leonard Nimoy ז’ל wrote about his decision to give Mr. Spock this priestly hand salute in his 1997 autobiography I Am Not Spock.)  With neither witnesses nor TV to help, is there another way to establish one's genealogy as a member of the priestly class? That's where the Cohen Gene comes in.  

The Cohen Gene

If all Cohanim are descended from Aaron, and the privilege is only transmitted from father to son, then perhaps being a Cohen can be genetically linked to a chromosome that is only passed from father to son. And there is such a chromosome. It's the Y chromosome, and all (fertile) men carry a copy that comes only from their biological father. (Quick recap: girls are XX and boys are XY. So all girls carry one X chromosome from mum and one X chromosome from dad. Boys, on the other hand, only get their X chromosome from mum, and their Y chromosome from dad. This can lead to other problems like hemophilia, which we've talked about elsewhere.) That's exactly what prompted  Karl Skorecki from the Technion, and colleagues from University College London, to analyze the Y chromosome in Cohanim and compare it to the rest of the Jewish population.  In 1997 they published a paper in Nature that looked at a special bit of the Y chromosome called YAP. Actually, they looked at 6 kinds of the YAP haplotype, (a haplotype being what geneticists call bunches of DNA sequences), and compared their frequency in Cohanim and non-Cohanim.    

Skorecki K, et al. Y Chromosomes of Jewish Priests. Nature 1997. 385:32.

As you can see highlighted, the YAP+ haplotype was found in only 1.5% of those who self-identified as Cohanim, but in over 18% of non-Cohanim.  The different frequency was found in both Ashkenazi and Sephardi Cohanim,  a result that the authors claimed was "consistent with an origin for the Jewish priesthood antedating the division of world Jewry into Ashkenazic and Sephardic communities."

“These Y-chromosome haplotype differences confirm a distinct paternal geneology for Jewish priests.”

— Skorecki et al. Nature 1997. 385: 32.

David Goldstein, who directs the  Center for Human Genome Variation at Duke University, also published a study on the Y-chromosome of Cohanim, using a sample that included the DNA swabbed "from the mouths of sunbathers on the beaches of Tel Aviv." Here is what Goldstein concluded:

Despite the high levels of variation, we could see a clear difference between Cohen and Israelite chromosomes. The most common chromosomes observed in the Israelites (that is, non-Cohen and non-Levite Jews) were found in only 12% of the Israelite individuals sampled. By contrast, more that half of the Cohen Y chromosomes were identical at the sites considered - that is, the majority of the self-identified Cohanim had the same type of Y chromosome. Even more remarkable, this same type of Y was found at high frequencies in both Ashkenazi (45%) and Sephardi (56%) Cohanim. (Goldstein, p.31)

Goldstein named this chromosome type the Cohen Modal Haplotype, and claimed that it showed "definitively" that Cohen status was not adopted (i.e. made up by some, eager for the benefits) but inherited.  And now things started to get really interesting. 

Dating the Original Aaron

So all, (OK, not all, but certainly most) of the approximately 500,000 Cohanim alive today seem to have originated from a common ancestor - a primordial Cohen. And just when did he live? Well, by analyzing small differences in the Cohen Modal Haplotype, and assuming that a generation time is 25 years, Goldstein et al. stated (with a confidence interval of 95%) that the origin of the priestly Y chromosome was "sometime during or shortly before the Temple period in Jewish history."

Not So Fast...

OK, a couple of things need to be noted here, before anyone claims that "genetics proves the Bible." First- as Goldstein himself notes in his book, his numbers may be off, by quite a bit:

Permit me here, after what was for me the first - and still one of the few - real thrills of discovery that punctuate the tedium and detail of science, the necessary reality check. Our results appeared to be a striking confirmation of the oral tradition. It even led to repeated claims in the press that my colleagues and I "found Aaron's Y chromosome." But although three thousand years is our best guess [as to when Primordial Cohen may have lived] the range of possible dates was and is very broad. Given our uncertainty about the ways mutations happen and how fast, we may be off by several hundred years or more in either direction. (Goldstein p.38).

Second, some later work done by Skorecki (he of the Technion 1997 Nature paper) suggests that the class of Cohanim may have had more than one common ancestor.  This work posits that there was not one primordial Cohen, but a few clans of Cohanim, from whom all later Cohanim are descended. (Or more technically stated:"...lineages characterized by the 6 Y-STRs used to define the original Cohen Modal Haplotype are associated with two divergent sub-clades...and thus cannot be assumed to represent a single recently expanding paternal lineage.")

And finally, work from Brigham Young University (and boy, those guys are really into ancestry) reminds anyone looking to do a quick Cohen DNA test to be careful.

The Cohen Modal Haplotype is observed in high frequency within the Cohanim, but also presents with significant incidence in other non-Jewish populations. The occurrence of the CMH in deeply divergent SNP haplogroups also indicates a lack of specificity of the CMH to the ancient Hebrew population. As such, inference of relation to Jewish populations for individuals or groups should be performed with caution when using the original CMH definition, as a false-positive result is likely.

 "A false positive is likely" - in other words, the test may show you are a Cohen, but really...you aren't. 

Genetic Testing - It's Not Just for Cohanim

And now that a Cohen "Gene" may have been identified, what about the rest of us non-Cohanim? Some have used genetic testing to discover a forgotten heritage or find long-lost cousins.  One rather keen family member of Polonsky rabbinic lineage (claiming in passing to be descended from King David, the Kalonymos family, and Rashi) used the presence of a "relatively rare R-M124 haplotype" on the Y chromosome to confirm a common ancestor and find a new marker that represents "Polonsky rabbinic lineage." (I confess I am jealous. My grandfather drove a black London taxi, and last time I checked, Rashi was not one of my known ancestors.) 

It's Not About Your Ancestors, It's About You

רמב"ם הלכות שמיטה ויובל פרק יג הלכות יב –יג 

ולמה לא זכה לוי בנחלת ארץ ישראל ובביזתה עם אחיו? מפני שהובדל לעבוד את יי לשרתו ולהורות דרכיו הישרים ומשפטיו הצדיקים לרבים שנאמר יורו משפטיך ליעקב ותורתך לישראל, לפיכך הובדלו מדרכי העולם לא עורכין מלחמה כשאר ישראל ולא נוחלין ולא זוכין לעצמן בכח גופן, אלא הם חיל השם שנאמר ברך יי חילו, והוא ברוך הוא זוכה להם, שנאמר: אני חלקך ונחלתך

ולא שבט לוי בלבד אלא כל איש ואיש מכל באי העולם אשר נדבה רוחו אותו והבינו מדע להבדל לעמוד לפני יי לשרתו ולעובדו לדעה את יי והלך ישר כמו שעשהו האלהים ופרק מעל צוארו עול החשבונות הרבים אשר בקשו בני האדם הרי זה נתקדש קדש קדשים. ויהיה יי חלקו ונחלתו לעולם ולעולמי עולמים ויזכה לו בעה"ז דבר המספיק לו כמו שזכה לכהנים ללוים, הרי דוד עליו השלום אומר: יי מנת חלקי וכוסי אתה תומיך גורלי

Why did the Levi'im not receive a portion in the inheritance in Israel and in the spoils of war like their brethren? Because they were set aside to serve God, to minister to Him and to instruct the masses about His just paths and righteous judgments... Therefore they were set apart from the mundane matters of the world. They do not wage war like the remainder of the Jewish people, nor do they receive an inheritance, nor do they acquire for themselves through their physical power. Instead, they are God's legion...and He provides for them...

Not only the tribe of Levi, but any human whose spirit moves him and who understands with his wisdom to set himself aside and stand before God - to serve Him and minister to Him and to know Him, proceeding justly as God made him, removing from his neck the yoke of the many mundane things which people seek - that person is sanctified like the Holy of Holies [in the Temple]. God will be his portion and heritage forever and will provide what is sufficient for him in this world, just as He provides for the Cohanim and the Levi'im...

Maimonides, in his Mishnah Torah,  reminds us about what is really important. It's not bringing a witness into town and telling everyone who your ancestors are. And it's not getting a DNA test to prove your stock. It's about searching for religious meaning in a world of materialism.  And that search is open to anyone, woman or man, Jew or not, Cohen, Levi, or even a plain old Yisrael.