GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2010-11 > 1290093900


From: Ann Turner <>
Subject: Re: [DNA] Relative/Family Finder math question
Date: Thu, 18 Nov 2010 07:25:00 -0800
References: <A3D1CA3DD2124FEF9867C6ED10DE9F02@PhilsPC>
In-Reply-To: <A3D1CA3DD2124FEF9867C6ED10DE9F02@PhilsPC>


*From:*
*Subject:* [DNA] software to calculate % contributions from various
ancestors
*Date:* Mon, 15 Feb 2010 12:28:50 EST
I posted an abstract about "Deconstructing Jaco" a couple of years ago (see
below), but I had problems with the software and did not pursue it at the
time. Now with 23andMe's Relative Finder, I'm more motivated. After some
correspondence with the author, I believe I've identified the problem, which
has
an easy work-around.

DECONSTRUCT uses GEDCOM files as input. It will find multiple pathways back
to an end-of-line ancestor and give you the "expected" amount of DNA you
inherited. The program may appear to freeze, so give it some time to
complete.


http://www.bi.up.ac.za/software/Deconstructp.zip

If DECONSTRUCT cannot find names in your GEDCOM, it may be because your
genealogy program uses the minimal GEDCOM spec, with the surname implied
with
//, like this.

0 @I1@ INDI

1 NAME Ann /Powers/
1 SEX F

DECONSTRUCT is expecting separate field for given and surname, like this:

0 @I1@ INDI
1 NAME Ann /Powers/
2 GIVN Ann
2 SURN Powers
1 SEX F

There is a free version of RootsMagic, which will import a GEDCOM and
export it with GIVN and SURN fields.

http://www.rootsmagic.com/Try/


===== source

Ann Hum Genet. 2007 Sep;71(Pt 5):674-88. Epub 2007 May 22.

http://www3.interscience.wiley.com/journal/117956739/abstract

Deconstructing Jaco: genetic heritage of an Afrikaner.

Greeff JM.

It is often assumed that Afrikaners stem from a small number of Dutch
immigrants. As a result they should be genetically homogeneous, show founder

effects and be rather inbred. By disentangling my own South African
pedigree,
that is on average 12 generations deep, I try to quantify the genetic
heritage
of an Afrikaner. As much as 6% of my genes have been contributed by slaves
from Africa, Madagascar and India, and a woman from China. This figure
compares well to other genetic and genealogical estimates. Seventy three
percent
of my lineages coalesce into common founders, and I am related in excess of
10 times to 20 founder ancestors (30 times to Willem Schalk van der Merwe).
Significant founder effects are thus possible. The overrepresentation of
certain founder ancestors is in part explained by the fact that they had
more
children. This is remarkable given that they lived more than 300 years (or
12
generations) ago. DECONSTRUCT, a new program for pedigree analysis,
identified 125 common ancestors in my pedigree. However, these common
ancestors are
so distant from myself, paths of between 16 and 25 steps in length, that my
inbreeding coefficient is not unusually high (f approximately 0.0019).

PMID: 17521310 [PubMed - indexed for MEDLINE]

Supplement 3 has some documentation about the program.

On Wed, Nov 17, 2010 at 5:50 PM, Phillip Goff <>wrote:

> List,
> >
> > I have a 23andme participant with an ancestry that includes a marriage
> > among 2nd cousins in the last 200 years. Is there a tool or method
> > available for estimating how much autosomal DNA that would be shared
> > between this person and another relative who traces to a common ancestor
> > in this same lineage?
>


This thread: