Ashkenazi genetic convergence over time

↑ dankbar ↓

Fri, Dec 02 2022, 1:24 pm

Someone mentioned avoiding certain cancers etc, on the flip side when bone marrow is needed, the more diverse, the ancestry, the harder is to find a match, being that most people stem from the same Eastern European regions, from all of their ancestors.

↑ Chayalle ↓

Fri, Dec 02 2022, 1:26 pm

jkl wrote:

I would have to run through numbers to work that out, but I dont see why we're focusing on geirim. That we have no control over. What we do have control over us to broaden our horizons. At the very least, we should put a stop to this polarization within ourselves and reverse these rigid community lines.

Just like it took years to get to the point, it will take years to undo. We just have to start working towards it. What is within our reach now is to try to at least stop the genetic line and then gradually work towards reversing it.

I do think that getting rid of certain stereotypes and being willing to consider shidduchim with a broader pool of people is a healthy perspective (in more ways than one).

↑ Chayalle ↓

Fri, Dec 02 2022, 1:31 pm

dankbar wrote:

So you have, on the one hand, an increased chance of (as an example) finding a bone marrow donor if you are Jewish and Ashkenazi (this example comes to my mind because I myself was found as a match for someone thru the Gift of Life Foundation). But perhaps by broadening the genetic pool, we might have less occurrences of certain cancers.

I know someone who recently received a kidney thru Renewal, and was told that they were an easy match and were matched pretty quickly (Renewal is amazing). However even in Ashkenazi circles I've heard of those who were more difficult to match (and drives were conducted for them to increase their chances of finding a donor.) It made me wonder why some are more complicated than others.

↑ dankbar ↓

Fri, Dec 02 2022, 1:34 pm

Chayalle wrote:

Because of the mix of ancestry. Even if it's all Eastern European, depends from which regions.

↑ dankbar ↓

Fri, Dec 02 2022, 1:37 pm

It makes sense that after Holocaust we are all more of the same. Being that 6/7th of European Jewry were wiped out, and only 1/7th survived, those that survived were mostly from the same regions.
I also wonder if our genes weren't mutated for sickness by experiment during holocaust, the way Jewish Ashkenazic are always deemed more prone to genetic diseases, more than the general public or other ethnic groups.

↑ Laiya ↓

Fri, Dec 02 2022, 2:25 pm

jkl wrote:

Here's where I'm not following. Ashkenazi Jews as a whole have a lack of genetic diversity, in or out of our communities.

How would marrying outside our communities but other Ashkenazi Jews, help?

↑ Chayalle

Fri, Dec 02 2022, 2:34 pm

Laiya wrote:

Here's where I'm not following. Ashkenazi Jews as a whole have a lack of genetic diversity, in or out of our communities.

How would marrying outside our communities but other Ashkenazi Jews, help?

Agree, unless she means Sephardim marrying Ashkenazim, I don't see the benefit. If my yeshivish DD's would consider marrying Chassidish boys (which they would not), it would not help genetically as my background a few generations ago is Chassidish (and our genes are probably way too similar).

I wonder if there's much genetic divergence between Jews from Poland, Hungary, Lithuania, Russia, and Germany etc...as they are not all that far from each other....

↑ jkl ↓

Fri, Dec 02 2022, 2:49 pm

Laiya wrote:

Here's where I'm not following. Ashkenazi Jews as a whole have a lack of genetic diversity, in or out of our communities.

How would marrying outside our communities but other Ashkenazi Jews, help?

Because despite the lack of overall diversity, there is still some level of diversity within ourselves.

Hashem designed the world so beautifully. He made most of the rare dangerous diseases to require either a set of recessive genes, duplicate mutations in the same allele, or multiple genes for the disease to present itself. The more closely related your spouse, the higher likelihood a recessive pair, duplicate mutations or a group of genes will be present in their offspring. The less closely related reduces that likelihood. So every step away from marrying a relative helps to some degree. Every step towards marrying a relative is detrimental to some degree. Maintaining a status quo is unlikely. Its either doing good or doing bad.

↑ Laiya ↓

Fri, Dec 02 2022, 2:50 pm

Chayalle wrote:

Exactly. And same even if she married a BT from Australia.

I'm not too familiar with Sfardi genetics, but I believe Sfardim and Ashkenazim are far closer to each other genetically, than to non Jews. So that might not solve anything.

The bolded is an interesting question. I would think they would not be different. Most Hungarian Jews for example originated in Poland, some Lithuanian communities were established by Jews running from Chelmenizki in Ukraine, etc. And "Ashkenaz" itself refers to Germany. I do find the OP surprising, that Jews were more divergent hundreds of years ago.

↑ jkl ↓

Fri, Dec 02 2022, 2:59 pm

Chayalle wrote:

See response above. Point to consider is not only among affiliations, but also community locations. For example, my grandparents and their surviving relatives all settled in Williamsburg. BH, they all had large families and their great grandchildren are now getting married. There have been multiple 2nd and 3rd cousin relatives getting married, as their shidduch pool is mostly limited to wmsbg and Monroe (KJ). If they would widen their horizons and consider other options from Israel, London etc. - even within their own chassidus, it would help somewhat.

Obviously, the effect is not comparable to marrying a Sefardi or even more so a Ger, but it still has an impact. The farther you reach out, the better it is. A small reach is still something.

↑ Laiya

Fri, Dec 02 2022, 3:02 pm

jkl wrote:

Putting aside known relatives, as long as we're still within the Ashkenazi pool, we're not going to be that diverse. I would wager a bet that if every woman who responded on this thread took the DNA test, all would find some genetic connection with the rest, and several would even discover a traceable connection or great-grandparents who lived in the same town.

Btw the genetics have a flip side. Sometimes "good' genes end up dominant.

↑ jkl ↓

Fri, Dec 02 2022, 3:07 pm

Laiya wrote:

I don't. While its true that people were separated by lack of travel options and lived in isolated shtetels, there was a further reach when it came to getting married. Many people physically went searching for spouses outside of their very small communities. They didnt have these rigid boxes we have nowadays - if someone was ehrlich and frum that person was considered.

The more we began separating into boxes and affiliations, the more smaller our circles became. And as we continue to move in the direction of creating more and more boxes, the bigger the problem will become.

↑ jkl ↓

Fri, Dec 02 2022, 3:09 pm

Laiya wrote:

You're missing my point. Just because we can't be that diverse, doesnt mean we can still be diverse to some level. Its not all or none.

And while good genes can also come to dominate, in this case the bad ones vastly outweigh any benefits of the good.

↑ dankbar

Fri, Dec 02 2022, 3:28 pm

I think in earlier times Jews migrated a lot because of persecution and being thrown out from one land to another.

Before war, I believe people married basically the people in their own shtetl, as they didn't travel that much. In that sense I think people do travel for shidduchim and move, and marry other people from across the world, nowadays especially by Yeshivish/MO/JPF.

You can have one mom, and one kid living in Florida, one in Australia, one in Toronto etc, wherever they found their bashert.

In chassidish there's a smaller pool, but someone from Monroe marrying someone from London, won't help if both zeides are from same shtetl in Hungary. Also by chassidish, many stick to their own chassidus, which stem from same shtetl back home.

↑ Amarante

Fri, Dec 02 2022, 3:35 pm

jkl wrote:

You are correct in terms of more potential issues arising in smaller gene pools and by limiting reproduction to a small subset, the issue increases.

I am not a geneticist but mutations of DNA happen all the time - it is the basis of variants in viruses.

So there might be a mutation that occurred relatively recently in an ancestor which is recessive or doesn't cause major issues unless the specific mutation is inherited from both sides. This might be something that is not known yet or the medical community doesn't realize it is genetic.

BRCA wasn't known to be genetically inherited until fairly recently and I believe it is considered to be a dominant gene. My father had breast cancer and was tested but did not carry the gene.

↑ jkl

Fri, Dec 02 2022, 4:04 pm

dankbar wrote:

No one is arguing againstl this. There will always be occasions where it makes no difference. But the key point is that THERE will be occasions where it makes the difference, thereby introducing the diversity. The more we open the doors, the more chances we give it to happen. Maybe a Williamburg chasid will have less of a chance but by broadening the horizon, it increases those chances.

It's not all or none.

↑ Raisin ↓

Sat, Dec 03 2022, 2:42 pm

Chayalle wrote:

In this context all ashkenazi Jews whether from Holland or Ukraine stem from the same small group of ashkenazi Jews living in the Rhineland.

I have Polish and German ancestry, on a DNA test it showed up as the same thing.

↑ Raisin

Sat, Dec 03 2022, 2:50 pm

And I definitely know people who think it is desirable to marry a second or third cousin...this type of thing should probably be discouraged.

I know some chabad families who do this, although in chabad there are many sefardim, and some gerim, so its not too difficult to be open to diverse shidduchim.

But there is a concept of Gezhe - meaning your family has been in chabad for many generations. Some people are really into that when looking for a shidduch. Confused

Not everyone though, recently I have seen it being much less of an issue.

I don't think encouraging my kids to marry yeshivish or (non Chabad) chassidish will help with genetic diversity. But being open to sefardi shidduchim will. And avoiding cousin marriages which is still practiced among some frum people.