The Human Family Tree Grows New Branches on Arbor and DNA Day

The Genographic Project, in partnership with Family Tree DNA, announces a new evolutionary tree.

Photo by Tim Laman

Did you know that this year, April 25th is both DNA Day and Arbor Day? In order to join in on the festivities and mark this calendric coincidence, National Geographic’s Genographic Project and Family Tree DNA are announcing the joint creation of the newest, largest, and most refined evolutionary tree of the paternally-inherited Y chromosome. In other words, the 2014 version of the Y-DNA tree is about ready to make an appearance. And the success of the DNA tree is due in great part to the Genographic Project’s GenoChip and the help from the more than 600,000 people that have joined this one-of-a-kind participant science project. From us at the Genographic Project we would like to say, Thank you!

What is the 2014 Y-Tree? The new Y-Tree is a chart of human relatedness showing how all men’s Y-chromosomes stem from an ancient ancestor in Africa more than 100,000 years ago. Since that shared common ancestor, his descendents have journeyed around the world and in the process accumulated mutations in their DNA that make them and their Y-chromosome relatives unique. Each mutation is a genetic event that occurred at a particular time and place in the ancestral journey. Today, all men carry in their Y-chromosomes a set of DNA mutations that charts that series of events. The tree is therefore the global genetic map of all these mutational events, showing how we are all related.

How different is the 2014 Y-tree to the current version used by the Genographic Project? With the new tree the number of branches nearly doubled, from 667 to more than 1200, and new connections have emerged. Haplogroup O, for example, has changed form showing new patterns of relatedness among East Asians and Southeast Asians. In general, the overall structure of the tree remained consistent with past versions, thus not affecting participants’ major haplogroup designations (G, J, R, and so on).

More branches mean greater geographic specificity – narrowing down where your haplogroup is found in the world – and this is where you can play an active role in the scientific process.  If you haven’t done so already, please fill out your profile questionnaire and tell us a little bit about your maternal or paternal genealogy in the Our Story section of the Genographic website.  By doing this, you are helping us to refine our knowledge of human migration patterns, in the process improving your Genographic results and those of other participants.

The Genographic Project's GenoChip
The Genographic Project’s GenoChip (Photo by Becky Hale)

How did my DNA help create the new Tree? By joining the Genographic Project your sample was compared to that of thousands of other participants, and your shared, but also your unique mutations helped us better understand the evolutionary process in which mutations occur, and thus helped us reconstruct the chronological order of mutations. In other words, if you shared 95% of your mutations with someone else, you shared a common ancestor to that point with that person, and your unique 5% marks a branch that distinguishes you from your “relative.”

What does this mean for my current results? Your current results will likely not change. However, if they do they would become more specific, thanks to the increase in our understanding of the branching patterns and the discovery of new branch tips on the tree.

When will Genographic implement the new tree? The Genographic Project team is working closely with Family Tree DNA to implement the new data now. In the next few weeks this process will be complete and announced on the Genographic Project website. Participants will then be able to log in to their results and see the changes.

 

Changing Planet

Dr. Miguel Vilar is the Science Manager for National Geographic's Genographic Project. Miguel is also a molecular anthropologist and a science writer. His fieldwork has taken him to remote places throughout the South Pacific, East Africa, Mesoamerica, and the Caribbean. In the laboratory he researches the modern genetic diversity of human populations from Melanesia, Micronesia, North and Central America, and the Caribbean. Miguel has published in several anthropology and genetics journals, as well as popular science magazines.