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Ancestral Family Tree DNA Testing / Re: So Proud of Great Diversity in My Ancestry
« on: Sunday 12 July 15 14:55 BST (UK) »
Dr Forster of Genetic Ancestry responds to the criticisms on this thread.
First he addresses the accuracy issue: -
"The reason is that I am puzzled why he/she considers the presented accuracy
"not remotely possible". Your results are good, but not as accurate as many
other clients we have analysed, who have closer matches in our databases, often
surname matches."
On the objections brought by davidft and Guy Etchells, he said: -
"The first comment is simply ignorant (that researchers have not sampled a
sufficient proportion of the human population to cover the main existing DNA
types). But there is perhaps a grain of truth in that a large survey of Africans
a couple of years ago did yield a previously unknown deep Y chromosome lineage
at low percentage. Similarly, some years ago my colleague Turi King found a West
African A-type in a Yorkshire family (surname Revis, I think), and according to
family records going back to the 1700s, there was no recorded African
connection. Roman slave trade perhaps?
It is difficult to find such surprises, underlining that we do have a fairly
detailed understanding of the basic structure of human genetics based on
existing samples.
The second point is a misunderstanding: when we say "tracing African ancestry",
we are simply saying it is possible (even trivial) to distinguish Africans from
non-Africans using DNA. It is NOT the same as claiming that Africans (or Jews or
the British) are genetically uniform. For example, it is easy to recognise that
Rodriquez and Morales are Spanish names, whereas Smith and Attenborough are
English names. It is NOT the same as saying that Rodriquez and Morales are the
same name. I think this is where your correspondent has got the wrong end of the
stick."
I don't intend to be the go-between for opposing arguments here, only that I found Dr Forster's arguments to be more coherent - even if I do NOT accept his findings or methods without question.
First he addresses the accuracy issue: -
"The reason is that I am puzzled why he/she considers the presented accuracy
"not remotely possible". Your results are good, but not as accurate as many
other clients we have analysed, who have closer matches in our databases, often
surname matches."
On the objections brought by davidft and Guy Etchells, he said: -
"The first comment is simply ignorant (that researchers have not sampled a
sufficient proportion of the human population to cover the main existing DNA
types). But there is perhaps a grain of truth in that a large survey of Africans
a couple of years ago did yield a previously unknown deep Y chromosome lineage
at low percentage. Similarly, some years ago my colleague Turi King found a West
African A-type in a Yorkshire family (surname Revis, I think), and according to
family records going back to the 1700s, there was no recorded African
connection. Roman slave trade perhaps?
It is difficult to find such surprises, underlining that we do have a fairly
detailed understanding of the basic structure of human genetics based on
existing samples.
The second point is a misunderstanding: when we say "tracing African ancestry",
we are simply saying it is possible (even trivial) to distinguish Africans from
non-Africans using DNA. It is NOT the same as claiming that Africans (or Jews or
the British) are genetically uniform. For example, it is easy to recognise that
Rodriquez and Morales are Spanish names, whereas Smith and Attenborough are
English names. It is NOT the same as saying that Rodriquez and Morales are the
same name. I think this is where your correspondent has got the wrong end of the
stick."
I don't intend to be the go-between for opposing arguments here, only that I found Dr Forster's arguments to be more coherent - even if I do NOT accept his findings or methods without question.