DNA testing - genetic genealogy

[Erato]

Generation time in the [modern - 20th century] USA was considered to be 28.5 years when I studied demography; granted, that was some time ago.

I agree with nickgc, DNA can be a useful tool for settling some questions and the more testing that is done, the more useful it will become.

[Nick29]

I have difficulty seeing what argument people seem to be trying to make against DNA testing.  It is just another tool, and the more people who use it, the better it might be for all of us.  At least the really bright people doing genetics think so.

Nick

I'm not making an argument for or against DNA testing, but people need to see it for what it is.   As I've said several times in the past, DNA testing is excellent for proving who isn't your ancestor, but not so good at proving who definitely is, because most of us share common ancestors.  (And I take your point about the time period for a generation - not that it makes much difference to the argument).

[acorngen]

Tisy,
R1b1b2a1b4c1 is in fact found in all of England France and Italy.  That particular group is also believed to have first come to Britain 1800 years before present and therefore sometime during the middle of the Roman Period.  It is believed to have started out as an Alpine Celtic ethnic group.  I have seen many people with this haplogroup over the last 12 months.  Now what about the mutations within it?  This is why I think DNA is not a tool that should be used in Genealogy because it really doesn't help.  This was conceded to me by an American who was at the WDYTYA show with the DNA company he works for. 

A friend of mine recently did an MtA test to prove she was of Romany descent but alas her DNA came back as typical UK MtA as well and no chance of her coming off Romany stock on the maternal line.  In that respect I think it is a good idea but not when trying to connect ancestors 7 generations before

ROb

P.S. Isnt it interesting the people suggesting DNA should be used in the main are Americans and those who seem to be against it are British

[Nick29]

If I was an American, and I had no idea about my ethnic origins, I might well be tempted to try DNA testing to try to establish which part of the world my forefathers came from.   However, using DNA to pinpoint families of the same name would be pretty fruitless, not only because of shared ancestors, but due to the fact that those with the same surnames did not originate from the same places.  For instance, take my grandfather's surname - HOLE - this is a fairly uncommon name, which originates from families who lived in a hollow, and in the UK in the 1800's, most people with that surname lived either in Yorkshire/Lancashire or Somerset, where there are some famous holes or hollows.  I've never seen any suggestion that the two 'tribes' were connected in any way, other than the derivation of the name.  The name WOOD or WOODS (incidentally my own g.g. grandmother was a WOOD) comes from people who lived in or near a forest or wood, and it's important to realise that 80% of England was forested, before Henry VIII chopped down all the timber to build his fleet of warships.  So you can't even narrow the WOOD surname down to a particular area or areas.

[Tisy]

Hi,

There is also research now which is looking at the possibility of L20 coming from the Bituriges Cubi celts of the old Kingdom of Berry, having migrated into central Germany in about 400BC and then being carried over to the British Isles with the Saxon invasion - controversial at the moment no doubt.  See David Faux's papers on line.  Steve Gilbert is the researcher looking at L20 in particular.  If you would like to have the link to his site let me know.

I am not going to try to convince you genresearch, as you have obviously made up your mind;  but I think you have to concede that genetic genealogy is here to stay and is becoming part of mainstream research.  You can call it what you like, but it is helping people to break down their brick walls and is proving a useful tool for those of us who simply do not have a paper trail.  The new autosomal test may prove to be of more help than the Y-DNA test - time will tell. 

I have no idea what you mean when you say that Americans are for DNA and British are not - this is a complete generalisation and not at all valid.  There are many British people who test because of illegitimacy or adoption;  Americans test in the hope of finding links with their origins, not because of some faddish idea that it is "the thing to do".  I am British, and I have tested.

Cheers,
Tisy

[acorngen]

Tisy,

Yes it was a generalisation and one that came about from my time spent on genetics forums reading and learning.  You are right my mind is made up about the subject but that wouldn't stop me adding my profile to the Burns project I just don't see the point.

I think arguing that L20 came to the UK after the date of 200AD is a valid one because it was around that time the Saxons started to cross the water into England but only started to invade in the 4th century.  The fact that some of the German auxillaries also came over during the second and third centuries would also fall into this debate.  If you have the link to Faux's paper I would be interested.

Yes DNA is here to stay and I just hope that it doesn't lead to even wilder claims that we are related to the queen etc than we get now.

Rob

[Tisy]

Hi Rob,

I will have to dig about for David Faux's link - will let you have it tonight.  Your remark about being related to the Queen brought a smile to my face;  there is a wonderful family site which actually lists Jesus Christ as an ancestor;  being in the same haplogroup as Charles Darwin just didn't measure up to this!  LOL!

Your contention about the 128 ancestors floored me a bit as well;  we are dealing with Y-DNA here (this is how we tested), so I take that to mean that if we have a common direct male line ancestor seven generations back - that's what it means.  The female line doesn't come into it at all.  Neither to all the other grandparents.  I will however go back to ftDNA and check this with them.

Cheers,

Tisy

[Redroger]

I have only 5 generations back to 1776 from my birth in 1940; average approx 35 years per generation. At this rate my 7 generations would go back to c1690.

[nickgc]

Redroger,

Thanks for elucidating.  I have wondered if some of your direct ancestors were fairly old when becoming fathers based on some posts of yours (I think I noticed one of your great grandfathers was born before my third great gpa - and I'm not young).

I presume though that the 5 generations you speak of are in a single line, and not an average across all the lines in your preceding 5 generations.

Starting with your children for ease of calculation (assuming you have children and they are of reproductive age), 5 generations back would be all their 32 3rd great grandparents from both your and your wife's side.  The average generation length would be an average of all lines, not just an average of one discrete line.  I.e. average reproductive age of you and wife for gen 1; avg repro age for your 4 parents for gen 2; avg repro age for you 8 grandparents for gen 3, etc.

Nick