What’s a CentiMorgan, Anyway? How DNA Tests for Family History Measure Genetic Relationships

If you’re doing DNA tests for family history, you may see lots of predicted cousin matches: 2nd, 3rd, 4th, etc…..But what does that predicted genetic relationship actually mean? Learn about centimorgans, the powerful genetic genealogy unit of measure, and how it helps your research.

genetic relationships and centimorgans

How DNA Tests Measure Genetic Relationships

When we are looking at genetic relationships, there are also many ways we can measure them. But ultimately, we want the testing company to tell us how likely it is that a particular individual shares a single, recent common ancestor with us. One factor in this calculation is to take into account the total amount of DNA we share with that match.

Currently, all the testing companies are reporting this sum in centimorgans (cMs).  Every company reports to you the total number of shared cMs, as outlined below.

  • AncestryDNA: Click on the match to access the personal profile page for that match. In the second section, under Predicted Relationship, you will see the confidence level. To the right of the confidence level, you will see a grey circle with a little “i” in it. Clicking there will show you the total amount of shared cMs as well as how many pieces of DNA you share.
  • Family Tree DNA: On the main match page for your Family Finder results, you will see the total amount of shared cMs in the third column.
  • 23andMe: You can see the percentage of shared DNA from the main DNA Relatives home page. To convert the percentage into centimorgans, just multiply your percentage by 68 (that will at least get you close). You can also see total shared cMs in the chromosome browser tool (go to Tools > DNA Relatives > DNA).
  • MyHeritageDNA: The total amount of shared DNA is shown on the main match page under the title Match Quality. MyHeritage also has a new DNA Match Review page. Click here to read more about that.

Centimorgan: A Genetic “Crystal Ball”

It is very tempting to think of a cM just like you would think of an inch or a centimeter, and for all practical purposes, that is okay. But it is actually much more complicated than that.

A cM is actually more like a crystal ball: it helps us predict how likely a piece of DNA looks exactly as it did a generation ago. This, in turn, helps us calculate how far back we should be looking for the common ancestor between two people.

But for our practical purposes, you can use the total amount of shared DNA, in combination with this chart compiled by Blaine Bettinger and the Shared cM Project, to better assess your genealogical relationship with your match based on your genetics.

To use the chart, take the total amount of shared DNA you have with a match, and look up that number in the chart to get an idea of what kind of genealogical relationship might best fit the genetics that you see. For example, if I share 69 cM with my match, we might be third cousins. But we might also be second cousins once or twice removed.

How do you figure out which one? Simply put: do genealogy research! It’s time to use traditional records and research skills to better understand the genetic clues in your family history mysteries.

My series of DNA quick reference guides can help you get the most out of your DNA tests for family history. I definitely recommend the value-priced bundle of all 10 guides. But I especially recommend the guides listed below if you’re to the point where you’re trying to understand what genetic relationships mean:

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Disclosure: This article contains affiliate links and Genealogy Gems will be compensated if you make a purchase after clicking on these links (at no additional cost to you). Thank you for supporting Genealogy Gems!

Digital Family History Book Collection Hits 200k!

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A milestone 200,000 digital family history books are now online at the multi-library Family History Books collection at FamilySearch.org. The growing collection, which began in 2007, includes “family histories, county and local histories, genealogy magazines and how-to books, gazetteers, and medieval histories and pedigrees,” according to the landing page.

Last time I looked for books here, I found one on my Homer ancestors. This time around, I found another gem: a book of children’s stories written about these ancestors! Digitally-archived volumes like county and local histories, published  family histories and others are so valuable because they are immediately accessible and because they are keyword-searchable. Try these keyword search strategies:

  • Look for only a surname (in case the first name is written different ways or a different relative is mentioned).
  • Search for the name of a neighborhood, street, church, school, business, type of work or other keywords that pertain to your family.
  • Use the Advanced Search feature to focus your search for a keyword in a title, type of publication (periodical, etc).

Once you’re reading a book, you can click on the info icon (a circle with an “i” in it on the upper right) to see more information about the book, including source citation and copyright information.

While the number of volumes online skyrockets, the online Viewer for reading them is only gradually improving. Here’s a TIP from FamilySearch staffer Dennis Meldrum: “Safari does not work well with the Viewer.” Neither do mobile devices like the iPhone or iPad. “The Viewer works best with IE or Firefox. It also works with Chrome, but the Adobe Tools do not work. We are aware of the limitations of the Viewer and are working to replace it by the end of the year.”

evernote_libraryWant to keep track of which genealogy books are on your shelf and which you’ve found online? Create an Evernote genealogy library! Click here to learn how to do that with books on your shelf, and then add additional titles with the links in Evernote. Sharpen your Evernote skills for genealogy by becoming a Genealogy Gems Premium member. This gives you a full year’s access to our Ultimate Evernote for Genealogy Education, with five (so far) full-length video classes for beginner to expert and five mini-sessions, too.

Land Ownership Maps: New Online Property Map Tools for U.S. Genealogy Research

Screenshot from First Landowners Project video, shown below.

Screenshot from First Landowners Project video, shown below.

Do you ever find it difficult locate U.S. property owned by your ancestors? Two online resources for land ownership maps are available by subscription at HistoryGeo.com, which might just prove helpful!

The First Landowners Project aims to map out the original landowners in public land states. Currently, they’ve charted about 8.8 million original landowners from 21 different states (Alabama, Arkansas, California, Colorado, Florida, Iowa, Illinois, Indiana, Kansas, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Nebraska, Ohio, Oklahoma, Oregon, Texas, Utah, Wisconsin). “We will continue to add more of the Western states soon,” says a recent press release. “Information on eastern states can be found on our frequently asked questions blog entry.” Watch a video demonstration of this project below. Click here to read a detailed description of it.

The Antique Maps Project is a growing collection of historical maps that contain names of U.S. landowners. Their comment: “Many of these maps are indexed and searchable, and the ones that are not will be (thanks to our volunteer labeling program).” Watch a video about this project below:

Learn more about great mapping tools for genealogy by searching our blog by the Sanborn Fire Insurance Maps Premium PresentationMaps category (do this from our home page, lower left side). Or become a Genealogy Gems Premium member to gain a full year’s access to video classes like:

  • 5 Ways to Enhance Your Genealogy Research with Old Maps
  • Google Earth for Genealogy (use Google Earth to identify an old photo location)
  • Google Earth: Follow Your World
  • Time Travel with Google Earth
  • and NEW! Sanborn Fire Insurance Maps

 

Genealogy Just Got More Exciting! The 1940 Census is Here

It’s not every day that a new record group becomes available that will help you learn more about your family history. But yesterday, April 2, 2012 was one of those special days! Who will you be looking for?  Do you plan on volunteering to help with indexing?

National Archives Releases 1940 Census

Washington, D.C. . . Ever wondered where your family lived before WWII;  whether they owned their home; if they ever attended high school or college; if they were born in the United States, and if not, where?  Unlocking family mysteries and filling in the blanks about family lore became much easier today with the release of the 1940 census by the National Archives and Records Administration.  By law the information on individuals in the decennial censuses, which is mandated by the U.S. Constitution, is locked away for 72 years.

1940 census archives.com

In a 9 A.M. ceremony in the William G. McGowan Theater, Archivist of the United States David S. Ferriero declared the 1940 census officially open. This is the 16th decennial census, marking the 150th anniversary of the census.  Performing the first search, Mr. Ferriero said, “It is very exciting for families across America to have access to this wealth of material about the 1930s.  Many of us will be discovering relatives and older family members that we didn’t know we had, picking up threads of information that we thought were lost, and opening a window into the past that until now has been obscured We now have access to a street-level view of a country in the grips of a depression and on the brink of global war.”

Dr. Robert Groves, Director of the U.S. Census Bureau added: “Releasing census records is an odd event for us; we spend all our lives keeping the data we collect confidential. However, once every 10 years, we work with the National Archives and Records Administration to release 72-year old census records that illuminate our past. We know how valuable these records are to genealogists and think of their release as another way to serve the American public.”

For the first time, the National Archives is releasing an official decennial census online. The 3.9 million images constitute the largest collection of digital information ever released by the National Archives.  The free official website http://1940census.archives.gov/, hosted by Archives.com, includes a database of Americans living within the existing 48 states and 6 territories on April 2, 1940.

“There is a great synergy between the National Archives and Archives.com stemming from our passion to bring history online,” said John Spottiswood, Vice President, Business Development, Archives.com.  He continued, “It has been a tremendous opportunity to work with the National Archives to bring the 1940 census to millions of people, the most anticipated record collection in a decade. In a short period, we’ve built a robust website that allows people to browse, share, print, and download census images. We encourage all to visit 1940census.archives.gov to get started on their family history!”

The census database released today includes an index searchable at the enumeration district level.  An enumeration district is an area that a census taker could cover in two weeks in an urban area and one month in a rural area.

To make the search for information easier, the National Archives has joined a consortium of groups to create a name-based index.  Leading this effort, FamilySearch is recruiting as many as 300,000 volunteers to enter names into a central database.

Questions asked in the 1940 census, which reflect the dislocation of the Great Depression of the 1930s, will yield important information not only for family historians and genealogists, but also for demographers and social and economic historians.  We learn not only if a family owned or rented their home, but the value of their home or their monthly rent.  We can find lists of persons living in the home at the time of the census, their names, ages and relationship to the head of household.  For the first time the census asked where a family was living five years earlier: on April 1, 1935.  This information might offer clues to migration patterns caused by the Dust Bowl and the Great Depression.  For the first time in the census, a question relating to wages and salary was asked. Persons 14 years old and over were asked questions regarding their employment status:  Were they working for pay or profit in private or nonemergency government work during the week of March 24–March 30, 1940?  Were they seeking work? How many hours did they work during the last week of March? How many weeks did they work in 1939?  What was their occupation and in what industry?

Great Scott! Genealogy Gems is Attending Federation of Genealogical Societies Conference

The Federation of Genealogical Societies (FGS) Conference for 2016 is “Time Travel: Centuries of Memories” and will be held in Springfield, Illinois. See what your future holds by learning about the past. Genealogy Gems will be there, and you’re going to love our line-up of free 30-minute classes in the exhibit hall (booth #200). Plus, enter to win our Grand Prize drawing! Here are all the details.

Make Your Future Whatever You Want, But Make it a Good One

TeamTimeCar.com-BTTF DeLorean Time Machine-OtoGodfrey.com-JMortonPhoto.com-07

JMortonPhoto.com & OtoGodfrey.com [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

With his iconic exclamation of “Great Scott!”, Back to the Future’s Dr. Emmitt Brown reminded us that the future is in our own hands. Make your future genealogy research “a good one” by attending this year’s conference.

This Federation of Genealogical Societies Conference will benefit the novice, the professional, and anyone in between. With over 160 sessions and 72 expert speakers from all over the world, you will be inspired to reach greater heights in all things genealogy.

Each day, a new set of classes will guide you through:

  • the U.S. Midwest (regional track)
  • the United Kingdom (British Isles and Commonwealth track)
  • the continental European research (ethnic track), to give you the latest and greatest in genealogy research.

If you missed early registration, that’s okay. Walk-in registration is available by clicking here. Enjoy all four days of inspiring classes, only attend a day or two, or just meander around the exhibit hall.

Free Stuff in the Exhibit Hall

The exhibit hall is always a favorite place to network and socialize with your genealogy buddies. Wander from booth to booth to see what the future holds for genealogists and gather up all the fun and free swag, too.

Most importantly, Lisa wants to see you for our free sessions that are back by popular demand! With such a positive response last year, Genealogy Gems will once again be hosting a series of free presentations at this year’s FGS conference. Join us in our Genealogy Gems Theater in booth #200 in the exhibit hall. Our 30-minute information-packed sessions will help you think outside the box for greater genealogy success.

Attend any of our sessions and sign-up to receive our free e-book of handouts for all the sessions. Want to plan ahead so you don’t miss a thing? Glance over the schedule below (click the button to download the schedule) and mark your can’t-miss sessions. (Not able to attend? Stay tuned because we will be announcing which sessions will be broadcast live over Periscope for free.)

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BONUS: Join Lisa in the FGS theater area of the exhibit hall
Saturday at 12:10 for
Top Google Search Strategies for Genealogists

FGS 2016 Genealogy Gems booth schedule

Grand Prize Drawing: Total Retail Value over $210

Presenters at the Genealogy Gems Theater have pitched in for this year’s Grand Prize drawing. The winner will receive:

…from Lisa Louise Cooke’s Genealogy Gems

…from Your DNA Guide Diahan Southard

…from Family Tree Magazine: an e-book bundle valued at about $100

Click here for the Grand Prize entry form, which also gets you the free e-book with all the session handouts. Drop the entry off at booth #200. The winner will be notified by email.

map of Genealogy Gems booth at FGS

Lisa will of course be presenting lectures during the daily sessions. Jump on over to our website page for even more information about the FGS Conference.

We’re looking forward to seeing you there, friends!

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