Guide to Genetic Genealogy

What is genetic genealogy? 

Genetic genealogy is a field that combines traditional genealogical methods with the insights provided by DNA testing to trace family history. Unlike traditional genealogy, which depends on historical records, oral histories, and family documents to trace lineage, genetic genealogy uses the genetic information encoded in our DNA. This approach can reveal relationships that might not be documented in historical records, bridge gaps in family trees, and provide a deeper understanding of one’s ethnic background and ancestral origins. DNA testing can help you pick up where the paper trail leaves off and achieve breakthroughs where living memory and historical records lead to dead ends. For example, you may locate an unknown relative who has records you haven’t seen yet, or discover a connection that resolves conflicting information in your tree.

Genetic genealogy is based on DNA matching: comparing the shared DNA between two individuals to understand how they may be related to each other. Using this information, it’s possible to locate unknown relatives, confirm relationships, and prove or disprove genealogical theories.

The process of genetic genealogy involves ordering a DNA test from MyHeritage. After receiving your test kit, you provide a sample of your DNA with a simple cheek swab, and ship it to our lab for analysis. After a few weeks, you’ll receive your results with information on your genetic makeup and a list of potential relatives who have also taken DNA tests, also known as DNA Matches.

Sometimes, understanding your relationships with your DNA Matches is straightforward. The company will provide an estimate of how closely you are related to a given match based on how much DNA you share. MyHeritage also takes your ages into consideration when calculating the estimate, which makes it more accurate.

However, the more distant your relationship, the more difficult it can be to understand exactly how you are related to a given match. Your goal is then to identify the Most Recent Common Ancestor (MRCA) you both share. MyHeritage provides a number of extremely useful genetic genealogy tools that can help you do exactly that, including the One-to-many Chromosome Browser, AutoClusters, and Theory of Family Relativity™. We’ll discuss what they are and how they work below.

Genetic genealogy tools

The amount of DNA you share with a given relative is only one piece of the puzzle. As you can see in the chart above, the smaller the percentage of shared DNA, the greater the number of possibilities for how that DNA Match might be related to you. DNA analysis tools can help provide more clues to narrow down those possibilities and determine who your most recent common ancestor was.

MyHeritage offers the most comprehensive set of genetic genealogy tools on the market, making it an ideal testing option for genetic genealogy.

Let’s explore them below.

Chromosome browsers and triangulated segments

One important type of DNA analysis tool is the chromosome browser. Chromosome browsers visually compare the DNA segments you share with your matches. They display the shared DNA across the 22 pairs of autosomal chromosomes, allowing you to see not only how much DNA you share with a relative, but also exactly where these shared segments are located. By comparing the locations of the shared DNA segments, you might be able to identify which DNA Matches are related to each other through the same common ancestor.

For example, if you share a given segment of DNA with your paternal grandfather, and the DNA Match you’re trying to identify shares the same segment, that indicates that you are likely related to the mystery match through your paternal grandfather’s side of the family. A DNA segment that you share with two or more matches is called a “triangulated segment.” Sometimes it’s helpful to compare the DNA of more than two or three matches at once. MyHeritage’s One-to-many Chromosome Browser allows you to compare your DNA with that of up to 7 matches.

AutoClusters

AutoClusters is a unique genetic genealogy tool available on MyHeritage that groups together DNA Matches who match each other as well as you, and presents them in a compelling visual chart. Using AutoClusters, rather than comparing individual DNA Matches on the Chromosome Browser, you can instantly see which of your DNA Matches are likely related to each other through a common ancestor. The clusters are color-coded and presented in a way that makes it easy piece together branches of your family. For example, if you have a DNA Match who appears in a cluster with several cousins on your maternal grandfather’s side, this indicates that the match likely shares an ancestor with your maternal grandfather.

Theory of Family Relativity™

Theory of Family Relativity™ is a feature exclusively available on MyHeritage that can be a game-changer in genetic genealogy. This feature combines DNA Match data with information from your family tree and historical records to supply plausible theories about how you might be related to a given match. For example, it might suggest that a DNA Match is your second cousin twice removed on your father’s side, based matches between this person’s family tree and yours, or a historical record that indicates a connecting relationship.

Watch the video to learn more about using Theory of Family Relativity™.

cM Explainer™

cM Explainer™ is an exclusive genetic genealogy tool available on MyHeritage. It calculates an estimated relationship based on shared DNA combined with the ages of the matching individuals. When you take a DNA test or upload your DNA to MyHeritage, the estimated relationship you see when reviewing your DNA Matches is calculated by cM Explainer™. You can also use cM Explainer™ as a standalone tool to calculate the relationship between you and a DNA Match from a different service.

Filtering, sorting, and labels

MyHeritage offers the most comprehensive variety of options for filtering and sorting your list of matches to help you focus on the DNA Matches that are most important to you. For example, you can choose to see only DNA Matches that are associated with a family tree, have a surname in common with you, or live in a certain location. Ever wondered whether you have relatives in Denmark or Australia? Using MyHeritage DNA, you can find out in a few clicks. You can also sort your matches by length of your longest shared segment, number of shared segments, or family relationships. You can also assign color-coded labels to your DNA Matches, which is very helpful when conducting genetic genealogy research: it allows you to organize your matches into groups that you can identify at a glance, such as matches with confirmed elationships and those without, or matches from your mother’s side or your father’s side of the family.

Uploading your DNA to MyHeritage

If you’ve already taken a test with another company, no need to test again — you can upload your data to MyHeritage and enjoy access to all MyHeritage’s DNA Matches and genetic genealogy tools. Uploading your DNA to MyHeritage and accessing your matches is free, and a small unlock fee of $29 gives you full access to MyHeritage’s Ethnicity Estimates and all the advanced DNA tools.

The science behind genetic genealogy

So how does genetic genealogy actually work?

While 99.9% of human DNA is identical, that 0.1% accounts for all variation between humans. DNA testing works by examining that small percentage of DNA to identify SNPs (single nucleotide polymorphisms), which are variations in base pairs of DNA that you inherited from your parents and ancestors, which distinguish your DNA from that of people who aren’t related to you. When you take a DNA test, your genetic material is compared to that of other individuals in the database. Your DNA Matches are those individuals who have identical sequences of DNA that you likely inherited from a common ancestor.

Nuclear DNA vs. mitochondrial DNA

Most of our DNA is located in the 23 chromosome pairs located inside the nucleus of each of our cells: one side from each parent. However, some of our DNA is located in other places in the cell. Mitochondrial DNA is located in the mitochondria, small organelles that are responsible for converting chemical energy from food into a form that can be used by our cells. Mitochondrial DNA is significant in genetic genealogy because unlike nuclear DNA, it is inherited exclusively from our mothers, and remains mostly intact when passing from mother to child through the generations. This means that your mitochondrial DNA can be traced all the way back through your maternal line for many generations.

Autosomes vs. X and Y chromosomes

Among the 23 chromosome pairs in the nuclei of our cells, there is one pair that determines biological sex. These are the X and Y chromosomes. A biological male person inherits an X chromosome from his mother and a Y chromosome from his father, while a biological female inherits an X chromosome from both of her parents. All the other chromosomes, which are not connected to biological sex, are called autosomes. This is significant to genetic genealogy because the Y chromosome can only be passed from father to son, which means that it remains mostly intact throughout the generations and can be used to trace paternal lines many generations back.

Mitochondrial Eve, Y-chromosome Adam, and haplogroups

Mitochondrial Eve and Y-chromosome Adam are conceptual figures in human evolution and genetic genealogy that represent the most recent common ancestors from whom all living humans inherit their mitochondrial DNA and Y chromosome, respectively. Mitochondrial Eve is traced through matrilineal descent, meaning the direct line of female ancestors, to a woman who lived approximately 200,000 years ago. Since mitochondrial DNA (mtDNA) is passed from mothers to their offspring without recombination, all humans can trace their mitochondrial DNA back to this ancestral “Eve.”

On the other hand, Y-chromosome Adam refers to the most recent common male ancestor from whom all living men inherit their Y chromosome, estimated to have lived around 200,000 to 300,000 years ago. Unlike mtDNA, the Y chromosome is passed from father to son, allowing paternal lineage tracing.

Haplogroups play a pivotal role in understanding our genetic heritage, acting as branches on the family tree of humankind. They are groups of similar haplotypes that share a common ancestor with a single-nucleotide polymorphism (SNP) mutation. By analyzing these mutations, scientists can trace back the origins and migration patterns of human populations. Haplogroups are categorized into various letters of the alphabet, with further distinctions made with additional numbers and letters. This system helps to identify and understand the genetic differences and similarities among human populations across the globe, offering insights into ancient human migrations and the interconnections of different groups throughout human history.

Shared DNA

Understanding how much DNA you share with a given relative is central to genetic genealogy because it provides an essential clue about how closely related you are.

You inherit around 50% of your DNA from each parent, and they in turn inherited 50% from each of their parents. That means you inherited around 25% from your grandparents. Each step removed within your family cuts the amount of DNA you share by around half. You can consult the chart below to see around how much DNA you share with different relatives:

Different types of DNA test

Autosomal DNA tests

Autosomal DNA tests are the most common type of DNA test used for genetic genealogy because they provide DNA matches from both sides of the family. This type of DNA test examines your autosomes, that is, the 22 nuclear chromosomes that are not sex chromosomes. Using this type of DNA test, you can connect with relatives from both sides of your family and understand your ethnic origins going back several hundred years. The MyHeritage DNA test is an autosomal test.

Mitochondrial DNA (mtDNA) tests

As mentioned earlier, mitochondrial DNA is passed exclusively from mother to child, so this type of DNA test is used to trace one’s maternal lineage and haplogroups. Using mtDNA, you can trace relatives going back many generations who are all related to the same maternal ancestor. This can be useful in genetic genealogy if, for example, you’re trying to determine whether someone is related to you through your maternal ancestors.

Y-chromosome DNA (Y-DNA) tests

The Y-chromosome is passed down exclusively from father to son, so this type of DNA test can be used to trace one’s paternal lineage and haplogroups. You can use Y-DNA testing to trace relatives on your paternal side going back many generations. One limitation that’s important to consider is that only biological males can take this test, since biological females don’t have Y chromosomes. If you don’t have a Y chromosome and you want to use DNA testing to study your paternal lineage, you’ll need to have a male relative take the test.While mtDNA and Y-DNA tests can add unique insights to your research, the autosomal test is the best option for overall genetic genealogy.

Which type of DNA test is best for genetic genealogy?

While mtDNA and Y-DNA tests can add unique insights to your research, the autosomal test is the best option for overall genetic genealogy.
The haplogroup information provided by Y-DNA or mtDNA is quite general, while the DNA Matches you receive through these tests cover only a narrow sliver of your relatives. By contrast, the autosomal test casts a much wider net, providing more matches on both sides of your family. Even if you’re looking for someone in your mother’s side of the family, you’re still more likely to get a larger number of useful matches to that person using autosomal DNA, because not all your maternal relatives share mitochondrial DNA — only those who inherited it directly from the same maternal ancestor. For example, your mother might have relatives through her paternal side that wouldn’t be matched with your with mtDNA. What’s more, the number of people who have taken mtDNA tests is relatively small, whereas you’ll have a much larger pool of matches to work with if you take an autosomal DNA test.

MyHeritage is home to one of the largest DNA databases in the world, and the most international one, making it ideal for uncovering your global roots and expanding your family tree beyond the U.S

Additional resources on genetic genealogy

Explore these articles from the MyHeritage Knowledge Base to understand genetic genealogy more in depth and learn more about MyHeritage’s DNA analysis features:

Genetic Genealogy For Family History Researchers:

The article on MyHeritage’s Knowledge Base outlines genetic genealogy as an accessible method for enhancing family history research through DNA data. It emphasizes that even without a deep scientific background, anyone can leverage genetic genealogy to break through research dead-ends, solve family mysteries, and expand family trees. The practice involves using DNA testing in conjunction with traditional genealogical sources, helping to find lost relatives, confirm relationships, and trace geographic origins. The article also provides tips on effective DNA testing strategies and utilizing tools offered by MyHeritage to maximize the benefits of genetic genealogy for research purposes.

Shared DNA: How Much DNA Do You Share With Your Relatives?

This article on the MyHeritage Knowledge Base explores the concept of shared DNA, clarifying that while humans share 99.9% of their DNA with each other, genetic genealogy focuses on the small percentage that varies among individuals. It explains how DNA matching works and provides insights into the amount of DNA shared with close relatives like parents, siblings, and half-siblings, using centimorgans to measure shared segments. The article also addresses the phenomenon of sharing DNA without recent common ancestry and highlights the role of segment length in determining the likelihood of relation.

How Do I Trace My Maternal And Paternal Heritage With MyHeritage DNA?

This article on the MyHeritage Knowledge Base details how to trace maternal and paternal heritage using DNA testing, focusing on the autosomal DNA test offered by MyHeritage. It explains the differences between autosomal, Y-DNA, and mtDNA tests and their relevance to genealogical research. While Y-DNA and mtDNA tests provide insights into paternal and maternal lines respectively, MyHeritage’s autosomal test covers a broader spectrum, enabling the discovery of relatives from both sides of the family. The article also discusses using MyHeritage’s advanced DNA tools for further exploration of one’s heritage.

How to Use AutoClusters on MyHeritage:

This article explains how to use AutoClusters, a feature that groups DNA Matches that likely descend from common ancestors. The tool organizes DNA Matches into color-coded clusters displayed in a visual chart and list format. Using this tool can help genetic genealogists determine potential relationship paths between DNA Matches and identify common ancestors.

How to Use Chromosome Browsers for Genealogy:

This article on the MyHeritage Knowledge Base details how chromosome browsers, especially MyHeritage’s One-to-Many Chromosome Browser, are instrumental in genealogy research. 
These tools allow users to see the DNA segments shared with matches, represented as colored sections on the human chromosomes. The visualization provided by the tool helps identify common ancestors by highlighting the specific DNA segments shared with relatives. Chromosome browsers can help break research deadlocks, enhance family tree construction, and clarify genetic relationships through detailed segment analysis. The article emphasizes the importance of understanding shared DNA segments for genealogical research, facilitating breakthroughs where traditional documentation may fall short.

Genetic genealogy success stories

People are making earth-shattering discoveries using genetic genealogy every day. Here are a few stories of people whose lives were changed forever by what they found using MyHeritage DNA:

MyHeritage Blog MyStory

A DNA Match Revealed Her Secret Egyptian Heritage and a Loving Newfound Family

Growing up among 10 siblings, Kate Valério often felt like the odd one out. Born in Portugal, currently living in Luxembourg, her brothers and sisters often teased her about how different she looked from the rest of them. A few months ago, she received a message about a MyHeritage DNA Match that turned everything she knew about herself on its head… and yet somehow, seemed to explain so much, from her dark complexion to the inexplicable fascination with Egyptian culture she’d felt since childhood. The DNA Match forced Kate’s mother to confess a secret she’d been hiding from Kate all her life: that Kate was fathered by an Egyptian man her mother had met in France 32 years ago. This revelation led Kate on a journey to connect with her Egyptian heritage, culminating in a trip to Egypt to meet her newfound siblings and bond with the large, warm family that welcomed her with open arms.

MyHeritage Blog MyStory

75 Years After 2-Year-Old and Mother Separated at Auschwitz, Their Families Find Each Other

Growing up among 10 siblings, Kate Valério often felt like the odd one out. Born in Portugal, currently living in Luxembourg, her brothers and sisters often teased her about how different she looked from the rest of them. A few months ago, she received a message about a MyHeritage DNA Match that turned everything she knew about herself on its head… and yet somehow, seemed to explain so much, from her dark complexion to the inexplicable fascination with Egyptian culture she’d felt since childhood. The DNA Match forced Kate’s mother to confess a secret she’d been hiding from Kate all her life: that Kate was fathered by an Egyptian man her mother had met in France 32 years ago. This revelation led Kate on a journey to connect with her Egyptian heritage, culminating in a trip to Egypt to meet her newfound siblings and bond with the large, warm family that welcomed her with open arms.

MyHeritage Blog MyStory

Thanks to MyHeritage DNA, She Had Both of Her Dads to Walk Her Down the Aisle

Kara Miller was adopted at two days old and grew up wondering about her birth family. However, her adoption was closed and she had very little information to help her with the search. She decided to apply for a free MyHeritage DNA kit through MyHeritage’s pro bono project, DNA Quest. That DNA test eventually led her to a biological aunt, who was able to connect Kara with her biological father, Mark. They met and immediately formed a bond. Kara got married shortly after, and thanks to this timing, she had both her adoptive and her biological fathers to walk her down the aisle.

MyHeritage Blog MyStory

Holocaust Survivor Orphaned as Toddler Finds His Family Thanks to a MyHeritage DNA Match

Until several months ago, Shalom Korai, 83, knew nothing about his past: not who his parents were, not his given name, not a single detail. He was a man without roots. Born 1941 in the Warsaw Ghetto, he was found at age two wandering around on his own, and he was rescued by Lena Kuchler-Silberman, a Jewish teacher and psychologist who had escaped from the transport to the Belzec extermination camp and lived in Warsaw under a false identity. Lena gave him the gentile-sounding name Petro Korczak, and he was smuggled, along with 4 other small children, out of the Warsaw ghetto in potato sacks. She then arranged for them to be placed in an orphanage at a cloister in Warsaw.

MyHeritage Blog MyStory

Fernando’s Journey: The Snowball Effect of a MyHeritage DNA Test

Fernando Hermansson Carabali and Ivan Andreas are a pair of brothers who discovered each other thanks to a MyHeritage DNA test. It would have been incredible enough of a story if it had stopped there — but it didn’t. First, they discovered an additional pair of sisters living in Spain. Then, Fernando’s wife — inspired by his success — took a DNA test herself, and she found a sister. Then, Fernando’s adoptive father, who had been adopted himself, took a test and found his own birth father. Finally, Fernando managed to find his mother, and traveled to Cali, Colombia to meet her for the first time. Watch this short documentary film about how a single DNA test led to a series of life-changing discoveries not only for Fernando, but also for those around him.



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