DNA MRCA - simple question!

[Mark Crawford]

Hi folks,

I have 4 exact matches for my 46-marker Y-DNA test via Ancestry.  The site shows an MRCA of 1 generation.  I believe they use this term to indicate a 50% probability of a match within 1 generation.

I've searched and can't for the life of me find the bell curve showing the percentages for earlier generations. I expect to see something like...

1 gen: 50%
2 Gen: 65%
4 gen: 95%

...or somesuch.  Can anyone help?

Also, I notice we don't seem to have a top-level forum for Genetic genealogy - is there a demand for one?

Mark

[Finley 1]

woo  Roots is 'Top level'   it covers ALL levels...

 

xin

[youngtug]

Have a read of this; http://www.rootschat.com/forum/index.php/topic,529585.0.html

[nickgc]

I would hope that Ancestry would either provide references to the type of thing you are after (since other commercial DNA testers do) or provide a forum for their clients to post questions.  Regardless, you are not going to get a simple bell curve graph.

Here are some data for the more popular 37 marker test (and I don't suspect you can do a linear extrapolation for 46 markers):  A 37/37 match implies a 50% probabilty of a match within 2 generations; a 90% probabilty that MRCA was within 5 generations; and a 95% prob. that MRCA within 7 gens.

I am very interested in how DNA genetics can help us with our genealogy, but really don't think it should be a separate part of RC.  There are plenty of websites already doing this and the expertise of some of their members is  vast.

Nick