How much DNA in FIRs (Fully Identical Regions) do relatives share?

Note: see here for a collection of links to Sim-cM-related pages. When we find a DNA match between two people, one way we can attempt to understand their relationship is to evaluate the amount of DNA shared. Resources such as The Shared cM Project, and DNA Painter’s relationship probability tool allow us to quickly evaluate the likelihood...

Using Sim-cM to Evaluate DNA Evidence

Sim-cM is a project set up to simulate shared DNA data for relationships of genealogical interest and to make the results freely available. So, what should we do with these results?

Sim-cM: An Update

A couple of weeks ago, I introduced Sim-cM - a project aiming to provide data from simulated pedigrees for different relationships of genealogical interest. I have now added more data, with results posted for 66 different relationships (including all of those listed in the Shared cM Project Version 3.0). For each relationship, I have included:...

A New Project: Sim-cM

I've been working on a project to simulate pedigrees and calculate the amounts of DNA shared between pairs of computer-generated relatives in different relationships. Using the Ped-sim Pedigree Simulator,1 I've generated data for eight relationships so far, with 10,000 simulated pairs of relatives apiece.  The main page for Sim-cM has summaries of the results that...

Children of John and Catherine (Doran) Fitzpatrick of County Tipperary

John Fitzpatrick married Catherine Doran 10 February 1872 in the Parish of Ballingarry, County Tipperary, Ireland. John was the son of Bryan Fitzpatrick, Catherine was the daughter of Pat Doran, and the witnesses were Joseph Taylor and Johanna Doran.1 While the family was often believed to be a large one (with more than a dozen...

Researching a Schenectady Family

In the course of some volunteer work at the Schenectady County Historical Society Grems-Doolittle Library (in Schenectady, New York), I got the opportunity to research a local family whose family history diary (started in 1909) had made its way to the library’s collection. Check out the library blog for a post I wrote about the family.

DNA & A Question of Paternity: Part 8 – Analysis with a new match

In search of information to clear up the uncertain paternity of “Bob,” I analyzed various records and DNA results for Bob and his genetic matches and came up with a list of four possible candidates for Bob’s father. There were no plans to make contact with genetic matches or their family members for targeted DNA...

DNA & A Question of Paternity: Part 7 – Bringing the evidence together

For the past several weeks, I’ve been describing a project for which I used various types of analysis to attempt to clarify the uncertain paternal ancestry of someone I’m calling “Bob” (all names in these posts have been changed for privacy). In this post, I’ll summarize the results of the analyses in the previous posts...

DNA & A Question of Paternity: Part 6 – Statistically testing hypothetical relationships

To predict the most likely locations for someone in a family tree (relative to DNA matches with a common ancestor), I've used the What Are The Odds? Tool to thoroughly test hypothetical trees and determine more or less likely relationships. As a complement to documentary research of a family, this has helped me narrow down paternal candidates for someone with uncertain genetic ancestry.

DNA & A Question of Paternity: Part 5 – Bringing together Autosomal & Y-DNA Results

Last week, I described using autosomal DNA matches, their relationships to each other, and their trees to start to construct a new family tree for someone (“Bob”) with uncertain paternity. The most recent common ancestor (MRCA) for Bob and some of these matches appears to be a woman born about 115 years before Bob, who...