Y-DNA testing can be a valuable tool for determining relationships among male descendants from the same common male ancestor. Especially for more distant connections where a paper trail is elusive.
The company Family Tree DNA (see https://www.familytreedna.com/) has provided Y-DNA testing services (Paternal Ancestry) for many years. They also allow for DNA matching service for those who have used their service for the test. Y-DNA tests check for specific areas of repetition (markers) within the Y-DNA. Depending on the cost of the test, the more markers are checked. Tests have been available to check 12, 25, 37, 67 and 111 markers. More recently a test for 700 markers is available and is called the "Big-Y" test.
Depending on which test is ordered, matches can be identified based on the results of the markers. The more two Y-DNA tests match, the more closely the two men are related to each other. A Y-DNA tree is available that establishes the ancestral tree for Y-DNA tests (see https://www.yfull.com/tree/). The detailed branches on the tree are dependent on the men who have taken the Y-DNA test, and the particular test that was taken.
Over time, a number of Atherton/Etherton and related 'cousins' have taken the "Big-Y" test and these tests have resulted in a detailed description of the relationships between these men. The chart above is a represention of these relationships. The branch BY73108 on the Y-DNA tree includes a number of families, and many of these families can trace their ancestors back to Lancashire, England.
Once the detailed branches are identified using the "Big-Y" tests, other Y-DNA tests can be added to the chart based on known, documented family connections, and using the available markers (12, 25, 37, 67, or 111) to confirm the connections on the chart.
It would be safe to assume the common ancestor at the BY73108 branch would have been named Atherton (see https://atherton.one-name.net/). Most other family names are a derivative of the Atherton name.
More tests will continue to provide more detail to the chart of family connections. Only time will tell if the unknown common ancestors will be identified.