How do I review a DNA Match?

To review a DNA Match, users can access an in-depth page presenting detailed information. This page includes contact options for the match, an estimated relationship, and sections such as Smart Matches, shared ancestral surnames, and shared DNA Matches, which indicate genetic relatives common to both individuals. Pedigree charts display up to five generations of direct ancestors, and the Chromosome Browser visually represents shared DNA segments, helping to identify common ancestors.

How do I use the Chromosome Browser — One-to-many?

The Chromosome Browser — One-to-many enables the comparison of DNA segments between a user (or individuals whose DNA kits are managed by the user) and up to seven DNA Matches. By analyzing these shared segments, including triangulated segments, users can infer relationships and identify common ancestors. This tool is accessed through the DNA Tools section of MyHeritage and allows for detailed visual comparison of genetic overlap across chromosomes.

What are the privacy options for my DNA data?

Users control their DNA privacy settings through the DNA Preferences section of their family site. These settings include enabling or disabling DNA matching, allowing others to view ethnicity estimates, and granting permission for DNA matches to view and download shared DNA segment data. Additionally, users can choose whether to display DNA badges in family trees and can opt into or out of the DNA Informed Consent Agreement, which allows MyHeritage to use anonymized DNA data for research. These options empower users to manage how their genetic information is shared and utilized on the platform.

What is the cM Explainer™ and how does it predict my relationship with my DNA Matches?

The cM Explainer™ is a MyHeritage tool that predicts possible relationships and their probabilities between DNA matches. It also estimates the most recent common ancestor(s) and visualizes relationship paths. This technology, developed in collaboration with Larry Jones, incorporates MyHeritage's age algorithm for enhanced prediction accuracy. Users can filter results by full or half relationships and view the probabilities of shared most recent common ancestors.

What does the Whole Genome Sequencing (WGS) upgrade mean for my DNA results?

MyHeritage DNA has upgraded to Whole Genome Sequencing (WGS), which reads nearly all of an individual's DNA for improved accuracy in DNA Matches and ethnicity estimates. Previously processed kits or uploaded DNA data will not be reprocessed with WGS, and individuals must order a new kit to access this technology. While the sample collection kit remains the same, the processing method in the lab has changed. Significant improvements from WGS will become noticeable over time, as MyHeritage builds a larger database of WGS-processed kits.

That DNA Match Could Be Your Second Cousin, Not

Your DNA test results are in, revealing a list of genetic matches. You share 98 cM with a mysterious person. Are they a first cousin once removed, or a half-great-aunt? The answer lies in understanding centimorgans, a key unit of measurement in genetic genealogy.

Explore your origins with a DNA kit - Order now

Genetic genealogy connects people by analyzing shared segments of DNA. When you and another person both inherited the same stretch of DNA from a common ancestor, you are considered a "DNA Match." The length of this shared DNA is measured in a unit called centimorgans (cM). The more centimorgans you share with someone, the closer your genetic relationship is likely to be. However, the amount of shared DNA can vary for the same relationship, making precise predictions a challenge.

Key Takeaways

Centimorgans (cM) Measure Genetic Distance: The more centimorgans you share with a match, the closer your likely relationship.
Charts Provide Relationship Probabilities: A centimorgan chart shows the range of possible relationships for a given amount of shared DNA.
Multiple Tools Offer Different Insights: Traditional charts provide raw probability, while newer tools offer more advanced analysis and filtering.
Context is Crucial: Shared cM is only one piece of the puzzle. Age, known family history, and shared matches are also vital for accurately identifying a relationship.

What Is a Centimorgan Chart and Why Do You Need One?

A centimorgan chart is a reference guide that correlates the total number of shared centimorgans between two people with the possible genealogical relationships they might have. Because the amount of DNA inherited from ancestors is random, a specific relationship type, like a first cousin, doesn’t correspond to a single cM value. Instead, it falls within a range. For example, first cousins might share anywhere from 553 cM to 1225 cM.

This variability means that a single cM value can suggest several different relationships. A match of 850 cM, for instance, could indicate a first cousin, but it could also point to a great-grandparent, a great-aunt or uncle, or a half-aunt or uncle. A centimorgan chart helps researchers see all these possibilities laid out, often with probabilities attached to each one. Without this guide, a researcher would simply be guessing.

Think of it as a detective's handbook. You have a clue (the cM value), and the chart gives you a list of likely suspects (the possible relationships). Your job as a genealogist is to use other evidence, like family trees and historical records, to determine which suspect is the correct one.

Comparing Centimorgan Charting Methods

Genealogists have several excellent options for interpreting shared cM data. While they all aim to solve the same problem, they approach it in different ways. The two main approaches involve using crowd-sourced probability tables versus integrated, platform-specific features that may leverage additional data for more refined predictions.

The Traditional Approach: The Shared cM Project

One of the most well-known resources in the genealogy community is the Shared cM Project. The project organizes this data into a chart that shows the average, minimum, and maximum cM values observed for hundreds of different relationship types.

Pros: Its strength lies in the sheer volume of its data, collected over many years. It is widely trusted and provides a comprehensive view of the ranges for many distant and complex relationships. It’s an excellent starting point for generating a broad list of possibilities for any given cM amount.
Cons: The chart is static and purely statistical. It provides the probabilities but offers no help in narrowing them down. A user must manually look up their cM value and analyze the list of potential relationships. It also doesn’t account for nuances like pedigree collapse or endogamy, which can skew cM values.

The Interactive Approach: The DNA Painter Tool

Another popular third-party tool is the interactive calculator at DNA Painter. Based on the same data from the Shared cM Project, this tool offers a more user-friendly experience. Instead of reading a static chart, you simply enter the number of shared centimorgans, and the tool generates a list of possible relationships along with their probabilities.

Pros: It’s fast, easy to use, and clearly presents the probabilities for each potential relationship. It removes the need to manually scan a large chart, making the process more efficient for beginners and experienced researchers alike.
Cons: Like the Shared cM Project, it is a standalone tool. You must navigate away from your DNA results to use it, and it relies on the same underlying statistical data. It cannot incorporate other crucial information from your family tree or DNA match profile, like shared matches or ancestral surnames.

A cluster chart showing connections between different DNA matches, used to identify common ancestors.

The Integrated Approach: MyHeritage’s cM Explainer™

Recognizing the need for a more integrated solution, MyHeritage developed the cM Explainer™. This feature is built directly into the DNA Match review page, providing analysis without requiring users to navigate to an external website. It analyzes the amount of shared DNA and presents a detailed view of the most likely relationships, their probabilities, and their corresponding cM ranges.

What sets this feature apart is its ability to provide deeper context and filtering capabilities. For instance, the cM Explainer™ can show a diagram illustrating how each potential relationship connects to you in a family tree structure. This visual aid is incredibly helpful for understanding complex connections like "first cousin twice removed."

Furthermore, it offers unique filtering options. You can choose to view only full relationships, only half-relationships, or both. This is particularly powerful when you suspect a half-relationship (e.g., a half-sibling vs. a full sibling) and want to focus your investigation. By isolating half-relationships, you can more easily evaluate scenarios that may involve previously unknown branches of your family, a common challenge in the search for biological family.

Pros: The integration within the MyHeritage platform is a significant advantage. All the information is in one place, alongside tools for contacting matches and exploring shared ancestral lines. The visual diagrams and ability to filter by relationship type provide a level of analysis that static charts cannot match. It also provides helpful definitions for each relationship type, aiding those new to genetic genealogy.
Cons: As a platform-specific feature, its direct use is for those who have tested with or uploaded their DNA data to MyHeritage. However, the principles and relationship probabilities it presents are grounded in the same science and can inform analysis on any platform.

Beyond the Chart: Essential Context for Accurate Predictions

A centimorgan value is a powerful clue, but it is rarely the whole story. To accurately pinpoint your relationship to a DNA match, you must combine the information from a centimorgan chart with other key pieces of evidence.

The Importance of a Match's Age

The age of your DNA match (if known) is one of the most critical factors. A significant age difference can immediately rule out many potential relationships. For example, if you share 250 cM with someone who is 50 years older than you, they cannot be your first cousin. They are much more likely to be a great-uncle, a first cousin twice removed, or another relationship from a different generation.

Conversely, if you and your match are close in age, you can likely eliminate relationships from different generations, such as aunt/uncle or grandparent. Always consider the generational gap when evaluating the possibilities presented by a centimorgan chart. Research suggests that cryptic distant relatives are common in many population samples, making age analysis even more important.

The Power of Shared Matches

Your shared matches are the other people who appear on both your DNA match list and your match’s list. This is one of the most powerful features for solving genealogical puzzles. By analyzing how you and your match are related to the same group of people, you can begin to triangulate your common ancestor.

Start by looking at the highest cM shared match. Do you know how you are related to them? If so, you can deduce that your mystery match likely descends from the same branch of your family. By grouping your shared matches into clusters representing different ancestral lines (e.g., paternal grandmother’s side, maternal grandfather’s side), you can quickly determine which part of your tree this new match belongs to.

A group of people from different generations smiling, representing a family brought together through genealogy research.

The Indispensable Family Tree

The most definitive proof of a relationship comes from documentary evidence. A family tree provides the framework for your investigation.

When you identify a promising relationship from a cM chart, turn to your family tree and your match’s tree (if available). Look for overlapping ancestral surnames, locations, or timelines. If your match does not have a public family tree, don’t be discouraged. You can often build a quick, unattached tree for them based on the information you have, such as their surname, known relatives, and the information from your shared matches.

The goal is to build their tree back in time until you find the intersection with your own. Autosomal tests tend to be very accurate, identifying nearly all second and third cousins, which helps in connecting these trees.

Tools like Smart Matches™ can automatically find connections between your tree and your match’s tree, revealing the exact relationship and the common ancestor with no manual work required. This seamless integration of DNA and family tree data is where the most profound discoveries are made, often unlocking family secrets that have been hidden for generations.

Centimorgan charts are a foundational tool in genetic genealogy, providing the scientific basis for estimating relationships. While traditional charts and standalone calculators are valuable, integrated features offer a more streamlined and powerful analytical experience. However, remember that shared cM is just the starting point.