The Big Y: What is it and why is it important?

The Big Y

I have updated the project “Wish List” and recommended that every member who is in the R-M269 haplogroup and able to do so order the “Big Y” from FTDNA. This post is a brief explanation of what the Big Y is and why I’ve recommended it.

What is it?

The Big Y is a DNA test that looks for a type of marker known as an SNP. The Big Y tests for thousands of known SNPs, as well as as-yet-undiscovered SNPs that may be unique to you or your lineage.

Why is it important?

Some SNPs are unique to one man and his descendants, which means they can be used to not only prove or disprove a relation between lineages, but also to assemble a family tree of sorts. The following image is a good example (click on it to enlarge):


Unlike a typical family tree, the relations shown here span centuries. You can see that the 28 participants listed at the bottom have a variety of surnames – McFarlin, McFarland, MacFarlane, Farlin, etc. – yet the SNPs these men share show they are all descended from the same medieval man. This man is represented at the top of the tree by markers BY674 and BY675. The ability to prove how different lineages and differently spelled surnames are connected is invaluable when researching the history of a clan or name, especially in the case of our particular project where the origins are vague and ambiguous.

As more men with Mac Pháidín surnames (McFadden, Macfadyen, etc.) take the Big Y, we will be able to assemble a similar tree (or trees) of our own. We will also eventually be able to see if the various Mac Pháidín lines are descended from or related to other clans or families. I’m pleased to announce that we have already had two project members place an order for the Big Y.

Anyone who has already taken a 37-marker STR test at FTDNA can order the Big Y. Simply sign into your account and click the blue Upgrade button at the top right of your screen.

Discuss this post on the McFadden Project message board:

MacFarlane SNP tree taken from Alex Williamson’s Big Tree web site:

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  1. […] – In order to prove or disprove connections within the project, particularly between men and groups that are M222+, we’re hoping more testers will take the Big Y. More info: The Big Y: What is it and why is it important? […]

  2. […] sort out the various McFadden branches. I have previously given an overview of the Big Y here: The Big Y: What is it and why is it important? Cost of the Big Y at FTDNA: $575 (on sale for $525). Only people who have purchased an STR test are […]