They only tested the Kohen! In a certain community they would test the people who claimed to be Kohen for DNA, and check the Torah observance of the people.
This not only to see if they are Jewish, but to find out if they were a "lost tribe" as well.
You have to understand, that if these people were not a lost tribe and no source on Judaism ever mentions converting them the traditional way, then they can practice Torah law all they want, they are still not Jewish unless they have proof they were properly converted or descend from ancient tribes of Jewry? Understand?
When you visit a community, the Kohen of the community never marries converts or intermarries. Therefore, if the Kohen can trace his DNA to match other Kohen, then it proves the community is Jewish. If not, they practive Torah, but are not reconnized as Jewish because there is no proof to trace them back to the tribes, and they need to be converted again before being recongnized as Jewish.
It is a complicated buissness.
Example: 500 Jews live in a community. They are all not tested. The 10 Kohen are tested since they do not marry converts, and if they match DNA proving they are a lost tribe of Israel then the community is recongnized. If not then the people need to be converted to Judaism, because no official Jewish authority ever converted them, and we do not have proof they are ancestors of biblical israel.
It is a very complicated matter dealt with by smart people in the fields that are needed. I am just infering ect... I am doing my best to answer your questions, on something I do not have top level classified info on.
Lavikor, I appreciate your attempt to provide a very detailed answer regarding how DNA helps to find the lost tribes. But, you don't have to. I read about it years ago. I actually understand the genetics part of it. You are working very hard at answering a question I am not asking.
I'm only wanting to know about what it takes to say that someone is a Jew. And I understand that if one's mother is a Jew, and you keep Torah that you are a Jew. That has been said more than once in this thread. And I also found it on Jewish websites.
Now, if one wants to prove that one is a part of one of the lost tribes, then I can see why one would need genetic testing. But to simply affirm that one is Jewish, that would not be necessary. I understand that there is a simple (serious and time consuming, but relatively straightforward) way of coverting to Judaism. So, surely if you go through all of that, and have your Bet Din, then you would be Jewish.
And then, as always, if this person was your mother, then once again, you would be Jewish. To prove that you are truly Jewish (not to prove that you are a member of a lost tribe), you should have to look any farther than either your mother, or your Bet Din. You got either one of those in your background, unless you've rejected your Jewishness, I would think that you were Jewish.
So, I was suggesting that perhaps my wife and I would convert. Once we had formally and official converted, and been declared Jewish by the Bet Din court, we would be Jewish. We would live Jewish life style and do everything that all other Jews do.
Do you agree, any children we would have in that scenario would also be Jewish? If you disagree, please, explain why.