How far back in ones DNA can they trace different ethnic origins in ones bloodli

Question:How does this work? My children have a Jewish paternal grandfather. Would that part of their heritage be picked up along with their Irish, Scotch, German, and Hungarian origins from my side? Please, someone who knows something on this topic, thank you!

Best Answer - Chosen by Asker: How does this work? My children have a Jewish paternal grandfather. Would that part of their heritage be picked up along with their Irish, Scotch, German, and Hungarian origins from my side? Please, someone who knows something on this topic, thank you!

DNA testing, in this vain, is normally not "open ended". It is usually done between two people (possibly separated by many generations) to determine the *probability* that there is a relationship. But even used this way, it is only a probability, not a certainty. A DNA test performed on a mother and child at the time of birth can only reach 99.993% certainty. That's pretty darn certain, but also not 100%.

Open ended DNA tests (done on a single individual) CAN in some cases give a higher probability to a certain ancestry. You mentioned a Jewish paternal grandfather. If a DNA test on you identifed the HEXA gene mutation associated with Tay-Sachs disease, then it is more probable that your ancestry has a connection with Askenazi (Eastern European) Jews in the 1800s. That is where the mutation is believed to have taken hold in a population. But again, probable. In actuality, the mutation (note that mutation just means change - doesn't imply positive or negative) could have occured with you, or one of your parents or grandparents who had no connection whatsoever with Eastern Europe. BUT, it is a higher probability that it came from that population as opposed to random mutation from another source.

There are a number of markers that have been "traced back" to a specific region as to its prevalence in the population. If you have these markers (and they are all uncommon mutations off "typical" DNA) then yes, there is a higher probability that your ancestry has a tie to these regions. But just a probability.

Open ended DNA tests aren't usually used. However, closed ended (comparison between two actual people) is done and can give a probability that the two people are in fact related (or not).

DNA goes way way back, and normally relates more to broader groups, ie, European, Asian, so forth. It does not give specific countries. Jewish is not a genetic classification, but a cultural and religious.
DNA does not prove who your ancestors were (by name/place). Normally, you still want to do the usual paper research to find those, then combine that with DNA results.
Don't forget.. tracing ancestors existed LONG before any use of DNA.