GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2005-06 > 1119003754


From: Robert Stafford <>
Subject: Re: [DNA] sub rugrat level
Date: Fri, 17 Jun 2005 03:22:34 -0700 (PDT)
In-Reply-To: <00ef01c572db$1f28d0a0$0301a8c0@bert>


Ian,

Using Y-DNA to test family trees or a limited hypothesis is actually pretty straightforward, so you can pretty much jump into it without a lot of technical knowledge. It is simply a matter of comparing sets of numerical results (haplotypes).

Getting into deeper ancestry (the subject of the majority of posts here) takes a much longer learning period.

The amount of pre-planning needed for a project depends on its scope. Some people start by testing a few trees first and possibly expanding later. If there is no family association in place, I would recommend this course of action.

If someone plans to undertake a project encompassing a full surname, it is wise to do a lot of planning before jumping into testing. Many unplanned projects turn out to be a waste of resources. Project planning entails getting key researchers on board, collecting family trees, finding needed donors, and setting up a website.

Without family trees and targeted testing, projects end up as large databases with little in the way of genealogically significant conclusions. If the family trees and right subjects can't be found, I would simply narrow the scope of the project.

The first goal of a family tree testing is to deduce the progenitor's haplotype. Test two cousins descended from different sons. If their haplotypes match, it is also the progenitor's. If they are only a near match, you will have to test a third and use values (alleles) which match on at least two out of the three. In some cases, you may have to test further.

Once you have deduced the ancestral haplotype, it is easier to assess whether people are related by comparing them to the ancestral haplotype. In a 10-15 generation tree, you will find that almost all match at least least 25/26 or 41/43 (using RG/DNAH's markers) with one or two 24/25.

Ancestral haplotypes also facilitates comparison between different families sharing the surname. Comparing two ancestors' haplotypes eliminates the "noise" of recent mutations.

Near matches corroborate the paper trail by showing that all the people in the tree are related. However, DNA testing cannot be used to prove exact relationships. First cousins can differ by more markers that sixth cousins. The paper trail is the only way to determine internal branching.

However, DNA testing can provide conclusive evidence that a person does not belong in the tree. This is its greatest value. There have been several cases where "proven" trees did not pass the DNA test.

Bob Stafford

IAN RITCHIE <> wrote:
Hi list,
Thanks for the rapid response. I've been idling away on the D & G List
whilst trying to fill in a few gaps in my Ritchie Tree,plus a few
sidelines,when some mention of DNA guided me to this list. It certainly made
me sit up even though I didn't understand much of it. I have done nothing as
regards testing,having only noticed it thus far on the far edges of my
vision and assumed it was still in its infancy,so I really must read up from
the many links supplied until I know what to do next.

As far as what I'm looking for I was really just trying to trace my tree
back as far as possible but the ancient origins of my line are of interest
to me too. Then of course there is the whole 'Out of Africa' theory and the
possible human descent from from a small group of females,or one female,in
Africa. But that's another story.

Ian Ritchie



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