They say, if you go back far enough, each one of us has a shared
ancestor with every other person on earth.
Scientists estimate that the most
recent common ancestor of all humans, probably lived in either Egypt or
Babylonia during the classical period. Evidently, we can all trace our
ancestry back to this person.
Assuming an average generation time of 20 years, this means that we are
all 120th cousins, descended from someone that was alive when the pyramids were
already aging structures. (Many millions of other people living at that time
also have living descendants, of course. The last common ancestor is simply the
one who is an ancestor to all of us, in addition to our many other
ancestors who are not common to everyone.)
Of course, within a given ethnic group, the most recent common ancestor
will be much more recent than that, especially so within a limited geographical
area with low ethnic diversity. Remember that, randomly, some people leave many
descendants and others leave none. If you take a country like Scotland, Sweden,
or Poland, you really don’t have to go back very far before you discover
someone that is a shared common ancestor to the vast majority of living
citizens. For example, in the lands of the former Mongolian empire, around 8%
of the population are direct descendants of Genghis Kahn and
that goes less than 800 years back. Even as far away as North
America, around 0.5% of men carry the Y-chromosome of the great Kahn.
Many millions of Americans of Irish ancestry trace their families back
to a specific county in Ireland, but the reality is that, if you’re Irish, you
are related to all other Irish people and probably a lot more closely than you
think.
In fact, everyone on earth with any trace of European ancestry probably
has a shared ancestor who lived in the early Middle Ages. Charlemagne has
been proposed as a possible candidate.
Family trees aren’t correct anyway
One thing that Ancestry.com won’t often tell you is that the genealogy
that you discover may not be accurate anyway. Inferences have to be made when
you are dealing with records that are hundreds of years old. There are many
surnames and first names that are quite common. There is no way to be sure that
the “Jacob Carter” that turns up in one record is the same “Jacob Carter” that
shows up in another from fifteen years later, even in the same general area.
Then, as now, many families were on the move. An isolated census record
containing only a name is nothing more than a low-resolution snapshot. There is
no way to know how many links and associations that genealogy reveals are
simply coincidence.
Furthermore, over the past two centuries, it was not uncommon for last
names to be changed, misspelled, or misattributed. Records were frequently
lost, recreated, or even forged. We think of our identities as relatively fixed
now because we have traceable identification cards, birth certificates, and
social security numbers from a very early age. But none of that existed until
recently.
There is a long article, with an America slant, you may wish to read on this topic
:
Nathan
H. Lents, Ph.D., is a professor of molecular biology at John Jay College,
of the City University of New York.
It's a skill we used to learn at school. I wore out the pair of socks I made in primary school and was very proud of them. I doubt I could turn a heel today, but you never know. Have just finished a sweater for DH and am now on a lemon yellow sweater for me. The pattern includes a christmas snowman, but I shall ignore that. Knitting again after so long made unacustomed muscles ache for a day or two, well a week, actually, but now I've got the stamina built up again, really enjoy knitting and don't want to stop. It is so much better than all those other bad habits I developed wnile watching tv!
