I asked “reasonably”. If there are records, for example, for the sake of this thread that’s sufficient. Even given the possibility of mistakes.
They can’t. The royal family of Jordan, which they overthrew back in the day, can.
I have an extremely distinctive family name that can be traced back to a single individual who lived in my home region in the 1500s.
Loach, and Danny Dyer, can all trace their ancestry far beyond Edward I. The royal linage goes right back to the House of Wessex in 534 with Cerdic, although some of the intermediate stages are dubious.
Confirmed ancestors go back to Ealhmund, born in 745 or so.
How does this square with the claim that Aboriginal Australians arrived in Australia at least 65,000 years ago? Are those who arrived back then not the biological ancestors of the Aborigines living today? Or do Aborigines not count as modern humans?
As for how far back a person could trace its ancestry, Icelanders have a genealogical database including over 900,000 people, over half of all who have ever lived in Iceland since it was first settled in 874.
There is a ryokan in Japan, the Nishiyama Onsen Keiunkan Hotel, which has been owned by the same family since 1,300 years ago.
Giving 25 years per generation, if you go 10 generations back you have 1024 ancestors in that 10th generation in 1774. At 20 generations in 1524 you have (on paper) more than a million ancestral lineages.
There’s a fair chance that at least one of your million lineages can supply genealogical documentation covering that entire passage of time. It might not be the one that ties you back to Vlad the Impaler, but for those lineages in Europe at least, its still a period of reasonable literacy, institutional record-keeping and laws that encourage capturing familial succession.
I remember reading (then forgetting) a statistic on how few people knew their grandparents, but remember being a bit appalled by it. If, say, half of us never knew them then we will know zero about the preceding generations, and may be very mis-informed about how far back you can go.
But the population has not been completely isolated. Because of the doubling effect each generation, a single migrant into a subpopulation can soon become an ancestor of everyone in that subpopulation, and vice versa.
If the population were panmictic (freely interbreeding with no structure, no isolated populations) the MRCA would be at only around 800 years ago. The longer figure of 2,300 years takes account of what we know of historical population structure.
Considering that branches of humanity split off much further back than that - Australia 40,000 or more years ago, Americas 20,000 years ago - odds are that the statistics only hold for each group.
I tried -not too deeply - to look up my ancestry. Since I didn’t find a link to anyone important, the best i tend to have is parish records from England. Those peter out back in the late 1600’s - they’d started keeping records a little before that, but then the Puritans decided interrupted the Church of England processes for a while. Some birth records indicate parents, some just the father, etc. Some churchs’ records were lost in fires. (IIRC the entire 1930 UK Census was lost in a warehouse fire, too)
No, the estimate takes all this knowledge of population structure into account. Because of the doubling effect each generation, it takes only a small amount of recent migration into and out of historically isolated populations to create common ancestry.
Is this guaranteed to have happened since 1770, when Cook first went there? The populations of indigenes and colonists have been quite separate over the last few centuries.
Guaranteed, no. It’s a statistical estimate. But the estimate does take into account everything we know (some of which derives from population genetic data, not just historical record) about population substructure and now isolated subpopulations have been historically.
Reliability is the bugaboo in all genealogy research. DNA makes it more accurate, but too many people simply copy what they see on websites like Ancestry rather than doing their own research, and believe me, there is a lot of unreliable crap on those websites. Also, if g-g-g-g-grammy had a fling with a passing snake-oil salesman, then all bets are off. Over the last 25 years, I’ve traced most of my family lines (a few were just impenetrable dead ends) back to early America, including to two Mayflower travelers. I’m reasonably certain that they are accurate, but sometimes you just have to take a leap of faith. I was also able to trace my father’s line (more recent immigrants) to Prussia with the help of a researcher in Germany who had access to church records and who could read old German.
One big problem with DNA analysis is that people think that a return showing .02% probability of Native American ancestry, for example (like mine does), means that they can claim Indian blood, rather than it just being an anomaly in the testing.
Same - I have a unique surname. They only reason why I cannot reliably trace back to the 1620s (and a couple of generations in England) is because Gen Sherman used a lot of government building as kindling. Now, we’re not sure whether Caleb and Benjamin were brothers or father/son.
I want to take this opportunity to plug wikitree.com, which seeks to build and improve a single tree with peer-reviewed documentation. It is completely free to join and use; they don’t sell anything.
I’ve stopped updating my own local RootsMagic database, because A) I prefer the peer-reviewed and validated scheme; and B) once I’m gone my local database will die-no one else in the family is interested enough.
I’ve traced back to Mayflower passengers Richard Warren and William Brewster some years ago, and WikiTree has helped me document a third. I’ve also found some errors or lack of citations in some of my important connections.
My folks have a book that traces my patronym back to 1634 arriving in Mass. Purely by coincidence, my parents didn’t know when they named me, I am the 14th with my same first name last name.
So I can get to the 1500s. We have a famous ancestor, the abolitionist Granville Sharp (1735 –1813), we can reliably trace our family back to him via my maternal grandmother. However when we went to the records that hold the Granville family papers, we discovered a family tree written by Granville Sharps brother in the 1700s where they traced their family back to Richard Grenville (made famous by the Tennyson poem, that I had never heard of but my Dad was taught at school):
I was actually more impressed by his grandson who earned the nickname “the Scoundrel” (for changing sides so much in the English Civil war, at one point attempting to lead a cornish independence movement):
I can trace my heritage back to the mid 1400’s. I am also fortunate enough to have 3 websites and 2 Wiki pages to use as a reference. 2 of my ancestors were the early settlers of Massachusetts, one came over from England in 1634, the other in 1637. They both were prominent enough to have their own Wiki pages. They may have actually known each other but it took a marriage in 1880 to combine the families, they are my paternal great grandparents. A distant cousin that now lives in Vermont has made a number of trips to England to trace our heritage even further. She found someone researching our name and together they found a common ancestor. This added a couple hundred years to our lineage and for the person in England, she found a couple hundred or so distant relatives in the US. On my great grandmother’s side, my heritage goes back to the early 1500’s with reliable records. This line fades out about then due to the lack of records and the infrequent use of surnames back then. Plus this name is also a common occupation for that area of England.
Courage, Chefguy.
This brings up issues with truly isolated populations. I saw a TV show which talked to a full-blooded member of the Tierra del Fuego tribe, which was about as isolated from the rest of the human chain as you can get. Unless their “genetic dilution” happened in the last 150 years or so, and then managed to spread to everyone on the island, it’s unlikely.
Then there’s the isolated Andaman Islanders, who have been hostile to outsiders for a millennia. Since their earliest contact at that time was slave raiders, it’s unlikely there’s genetic dilution there. They’re thought to have walked to the islands when water levels were low during the height of the ice age.
For the rest of Eurasia, there’s enough situations of rape during warfare and regular trading of women between tribes to help dilute most genetics.
Wikitree nevertheless has a lot of material contributed by people whose enthusiasm transcends their research and critical thinking skills.