By: Goran Runfeldt

The mix of genes and geography is the most potent recipe for studying human history. Phylogeography has attempted that feat since the 1980s, and we are taking it one step further with Globetrekker! How did your ancestors trek across the globe?

Editors Note: This is part one in a three-part series about Globetrekker, phylogenetics and human history. Read part two here:

In our Big Y customer surveys, the most requested feature has consistently been a more detailed migration map.

If you have taken a DNA test for genealogy purposes, chances are you are interested in learning where your surname line came from. The Y chromosome, with its unique property of being inherited in its entirety from father to son over generations, without mixing each generation like most of the other DNA in our genome, offers an opportunity to go back in time on the direct paternal line, much further than regular DNA tests. When did your lineage arrive in your ancestral location and where did it come from?

Based on Big Y test results, we have constructed the Y-DNA Haplotree, or the Y-DNA Tree of Mankind, a large family tree spanning over 200,000 years of human history, from Y-Adam to historical times. With the Big Y Age Estimate feature, released a year ago, we attempted to answer the “when” question for each genetic ancestor (haplogroup) in the tree. Now, with Globetrekker, we are taking another step to help answer the “where” question for your paternal line ancestors and “how” they got there.

Globetrekker highlights

      • Globetrekker is a new exclusive Big Y feature.
      • It is based on the largest Y-DNA tree in the world and the largest database of high-resolution samples with detailed paternal line ancestral information.
      • It uses advanced phylogenetic algorithms that consider topographical information, historical global sea levels, land elevation, and ice age glaciation.
      • It provides a new world map that shows the ancient sea levels around the Last Glacial Maximum, such as Doggerland.
      • It features a personalized animation spanning 200,000 years of your history, from Y-Adam to your Big Y haplogroup.
      • It contains 48,000 paternal line migration paths covering every populated continent and growing every week.
      • It contains an integrated tree browser that allows you to explore the Y-DNA Tree of Mankind in a completely new way.

Just like our Y-DNA tree, the lineages on the map expand and get more refined with each new Big Y result. Here’s a quick look at Globetrekker in action.

How to access Globetrekker

Globetrekker is only available to Big Y customers. You need to sign in to a FamilyTreeDNA kit with a Big Y test to access the new report.

Step 1: Sign in to your FamilyTreeDNA account.

Step 2: In the Big Y section, follow the Discover™ Haplogroup Reports link.

A screenshot of the Discover Haplogroups Reports widget

Step 3: Click the new Globetrekker menu link.

A screenshot of the Discover menu

How to use Globetrekker

      • Take a look at your new migration map. The map application is interactive and allows you to zoom, pan and click on elements. The line across the map shows the estimated ancestral migration path of your direct paternal line, all the way from Y-Adam around 200,000 years ago until your most detailed Big Y haplogroup whose location we could estimate.
A screenshot of the Globetrekker world map
      • Every haplogroup has a unique migration journey. The colors and routes will be different depending on the Y-DNA haplogroup and all the other participant locations.
      • The background map highlights topographical features. The dark green areas show the maximum land extent from when the global sea levels were the lowest during the height of the last ice age. These areas are now underwater, but they were once fertile land where people traveled through and lived for millennia.
      • Press the Play button to start the animation. You can adjust the animation speed with the other button and pause and rewind at any time. The glacier extent shows how parts of the world were covered in ice during different time periods around the last ice age.
      • Notice the Timeline below the map and how it scrolls to follow the migration path. You can use the integrated tree to orientate and navigate up and down the tree.
A screenshot of the Globetrekker timeline

Try the many different display options in Globetrekker

A screenshot of the Globetrekker display options
      • Ancient Connections: See how your lineage connects with and diverged from lineages unearthed from archaeological remains across different time periods, cultures and locations. Each branch point along your ancestral path can hold an interesting connection!
      • Simplify Lines: See direct lines connecting your haplogroup locations instead of the regular lines which are estimated based on the topography. This can often give an easier overview!
      • Corridors: These elements highlight the likelihood of different migration paths based on the landscape. You can adjust the Corridor Opacity to make it look just right for your view. Corridors are automatically hidden during animation.
      • Descendants: Descendant shapes show sibling lineages to your haplogroup and how they migrated over time. Try showing it for an ancestral haplogroup to see how your cousin lineages spread out in different directions. Each lineage is assigned a color that corresponds to triangles in the Timeline.
      • Hotspot: Shows the uncertainty around your haplogroup location based on all the geographical information from the descendants. The more geographically distant the descendants are, the larger the uncertainty will be.
      • Sibling Lines: In addition to your own ancestral line, this option shows the lineages that went other ways and the migration paths leading up to your Ancient Connections. This option is automatically toggled together with Ancient Connections, but you can also toggle in independently.
      • Earliest Known Ancestor: Your own self-reported Direct Paternal ancestor information is displayed by default when you view your own haplogroup, and you can toggle it on and off.
      • Colored Terrain: Too many colors? Try the toned-down version of the map to increase the contrast between features and terrain.
      • Fullscreen: Use this feature to fully immerse yourself into the map. Click the icon in the top right corner of the map. Even without the Timeline, you can still navigate up and down the tree by clicking on haplogroup points and descendant shapes.

Things to keep in mind

Unlike the Big Y age estimates, which are based purely on the tree structure and genetic data, the Globetrekker algorithm combines the Time Tree with self-reported ancestral location information from our users. We combine this information with data from population genetic studies and ancient DNA from archaeological remains, but ultimately your Globetrekker migration path will be mostly based on the information you and your Big Y matches have provided in the Earliest Known Ancestor settings. This is worth keeping in mind when looking at your results.

Phylogeographical reconstruction depends on the assumption that descendants, more often than not, live in some geographical proximity to where their ancestors were. This of course holds less true in the global contact era we live in, where anyone can take a ship or fly to any other part of the world in a short period of time. For this reason, we have focused on reconstructing pre-Columbian migrations, which means that European and African descendants in the Americas and Oceania will see their migration paths end in the original continent.

In the future, we plan to incorporate historical information from family trees in order to also show the New World migrations.

Globetrekker caveats and known limitations

Here are some limitations that are currently listed under the caveats section on Globetrekker. The list will be updated as issues are identified and resolved.

      • The algorithm is based on the assumption that present-day populations tend to live near their ancestral locations. When this assumption is false, such as when an entire population relocated from its original location, the algorithm will not be able to estimate the original location. (Example: Jewish Diaspora)
      • Pre-Columbian migrations are targeted and later migrations to the New World are not shown here.
      • Land routes are often preferred over water routes, which may be inaccurate for the age of sea travel. (Example: Mediterranean sea travel)
      • Although the algorithm attempts to compensate for sampling bias (i.e., people from some countries and cultures are much more likely to take a DNA test than others) and we include data from many population genetic studies to fill the gaps, many countries and populations are under-represented. This can make it hard to estimate the true origins of haplogroups that originate from those places and peoples.
      • Freshwater lakes are currently not considered.
      • Climatic effects, such as the aridity of the Sahara Desert, or conversely, the lushness of the Green Sahara (African humid period), are currently not considered.
      • Ancient Connections for each ancestral split are automatically selected to show the oldest archaeological connection for each sibling lineage.
      • The migration path location at any given time is interpolated assuming a steady migration pace between haplogroup locations.
      • The map always shows the maximum land extent for when the sea level was the lowest (Last Glacial Maximum, around 20,000 years ago) and currently does not change with the time slider.
      • Earliest known ancestor locations in Hawaii (Kānaka Maoli) are currently not working correctly. This will be addressed shortly.
      • Due to the large geographical uncertainty, countries larger than 10,000,000 km² (i.e. Russia) require a more detailed province or location than just country information for the sample location to be included in the calculations.

Unlock your genetic story with the FamilyTreeDNA Globetrekker report

Log in to your FamilyTreeDNA account and explore your new Globetrekker report! Make sure that your Earliest Known Ancestor Location settings are up to date.

This is part of our Discover beta releases, where we are giving users early access to new and exciting features. We want your feedback so that we can keep improving, so please take a minute to fill out our survey after you have tested out this new tool!

If you like it, please feel free to screenshot, record videos and share with your friends and family.

About the Author

Goran Runfeldt

Head of Research and Development

Goran is a genetic genealogist with a technology background. He is a driver behind many FamilyTreeDNA tools & features including the Block Tree and the Discover platform & Y-DNA reports. He is also a mitochondrialist in the Million Mito Project.

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