So What Do I KNOW About My Family Now?
Great question, and the answer is "a lot!" But there are limits, and we've discussed many of them in detail in the past few posts. Here are the highlights - some general conclusions and cautions.
There has never been a better time for those interested in their family history to do an autosomal DNA test - the standard offered by all of the popular companies like Ancestry, 23andMe, My Heritage, Family Tree DNA etc. At present more than 20 million people have done so - and that almost certainly includes a lot of people who share some ancestry with you. Add to that the enormous ongoing efforts at digitizing historic records from many countries, and bringing them online along with tools like optical character recognition (OCR) and powerful searching features. It has never before been possible to go so far back into your family's past without leaving your desk!
Autosomal DNA (measured in centimorgans, or cM) can provide conclusive evidence about people to whom we are closely related, at least within 5 generations (for example, 3rd cousins sharing a set of great-great grandparents). And while we all inherit 50% of our DNA from each parent, your non-identical siblings didn't inherit the SAME 50% as you did.
The closer the relationship, the more confidence we can have in our conclusion. As we get 5 to 7 generations distant (3rd to 5th cousin ranges), the likelihood increases substantially with each successive generation that we can be related and yet share no DNA. The smaller the match amount, the wider the range of relationship possibilities.
And DNA doesn't lie - if you have a big match with someone unexpected, or a complete lack of match with a close relative, there's a story waiting to be told, or to be kept. Shared matches above 15 cM (and in most cases as low as 10 cM) can be safely assumed to be truly related.
This also means that we need to do the research to establish our family tree. DNA can help validate that tree when used together with the records and other evidence. The testing companies all give us Shared Ancestor Hints when a DNA match has one of our ancestors in their tree as well. And just as with our own trees, those Shared Ancestor Hints are only as good as the research that produced them!
Furthermore, sharing a meaningful amount of DNA with someone who has the same distant ancestor in their tree only confirms a relationship. To know HOW we are related, we must further investigate specific chromosome segment(s) inherited from a common ancestor. While that type of analysis is not currently possible at Ancestry, some of these tools are available at GEDMatch, MyHeritage and FamilyTreeDNA.
When it comes to family trees, there is no "done" or "complete" in the big picture. While DNA can answer many questions, invariably it leaves a great many more that, with the current state of technology and available records, we may simply not be able to answer. So we take satisfaction every time we have a successful new discovery, while enjoying the journey and the many destinations we reach along the way. And we do our best to leave our work for another generation to pick up and continue someday :).
Those ethnicity estimates can be fun, or frustrating, but they are at present a less precisely developed science and vary somewhat widely between testing companies. They predict our origins in a timeframe of 300 to 1,000 years ago, while our genealogical bounty of shared segments and matches is most useful from the present to generally 150 to 250 years in the past.
There is good news: you can do much of this work on your own, if you'd like to take the time to climb the learning curve. But there is better news: I already have, and I can help you make sense of your top matches, identify where you might want to explore further and what other family members you might want to test. I'd be delighted to help you make some big leaps back into your family's past - please email me about my consulting work.
There has never been a better time for those interested in their family history to do an autosomal DNA test - the standard offered by all of the popular companies like Ancestry, 23andMe, My Heritage, Family Tree DNA etc. At present more than 20 million people have done so - and that almost certainly includes a lot of people who share some ancestry with you. Add to that the enormous ongoing efforts at digitizing historic records from many countries, and bringing them online along with tools like optical character recognition (OCR) and powerful searching features. It has never before been possible to go so far back into your family's past without leaving your desk!
Autosomal DNA (measured in centimorgans, or cM) can provide conclusive evidence about people to whom we are closely related, at least within 5 generations (for example, 3rd cousins sharing a set of great-great grandparents). And while we all inherit 50% of our DNA from each parent, your non-identical siblings didn't inherit the SAME 50% as you did.
The closer the relationship, the more confidence we can have in our conclusion. As we get 5 to 7 generations distant (3rd to 5th cousin ranges), the likelihood increases substantially with each successive generation that we can be related and yet share no DNA. The smaller the match amount, the wider the range of relationship possibilities.
And DNA doesn't lie - if you have a big match with someone unexpected, or a complete lack of match with a close relative, there's a story waiting to be told, or to be kept. Shared matches above 15 cM (and in most cases as low as 10 cM) can be safely assumed to be truly related.
This also means that we need to do the research to establish our family tree. DNA can help validate that tree when used together with the records and other evidence. The testing companies all give us Shared Ancestor Hints when a DNA match has one of our ancestors in their tree as well. And just as with our own trees, those Shared Ancestor Hints are only as good as the research that produced them!
Furthermore, sharing a meaningful amount of DNA with someone who has the same distant ancestor in their tree only confirms a relationship. To know HOW we are related, we must further investigate specific chromosome segment(s) inherited from a common ancestor. While that type of analysis is not currently possible at Ancestry, some of these tools are available at GEDMatch, MyHeritage and FamilyTreeDNA.
When it comes to family trees, there is no "done" or "complete" in the big picture. While DNA can answer many questions, invariably it leaves a great many more that, with the current state of technology and available records, we may simply not be able to answer. So we take satisfaction every time we have a successful new discovery, while enjoying the journey and the many destinations we reach along the way. And we do our best to leave our work for another generation to pick up and continue someday :).
Those ethnicity estimates can be fun, or frustrating, but they are at present a less precisely developed science and vary somewhat widely between testing companies. They predict our origins in a timeframe of 300 to 1,000 years ago, while our genealogical bounty of shared segments and matches is most useful from the present to generally 150 to 250 years in the past.
There is good news: you can do much of this work on your own, if you'd like to take the time to climb the learning curve. But there is better news: I already have, and I can help you make sense of your top matches, identify where you might want to explore further and what other family members you might want to test. I'd be delighted to help you make some big leaps back into your family's past - please email me about my consulting work.
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