This project is about a Y-haplogroup, which defines a group of men by a shared set of inherited features in the DNA of their Y-chromosome. This implies they have a patrilineal ancestor in common, because only males carry a Y-chromosome, which they inherit from their father. The major Y-haplogroups were formed thousands of years ago, and therefore each group can today include thousands to millions of men. For an introduction, you can visit the Y-DNA Haplogroups project, the DNA Testing project, or start at the beginning with the DNA Primer project.
This haplogroup project's name uses the older, now secondary, hierarchical format for Y-chromosome haplogroup names. Because the haplogroup names under this earlier system would change with the identification of new branches, it's no longer possible to know unambiguously to which current haplogroup this designation refers. Anyone with an old test result that assigned them to a Y-haplogroup with this name should update their information to use a shorthand format name that references a defining SNP.
Please see the J-P58 project for more information about this Y-haplogroup.
Naming History
In the preferred shorthand notation, the Y-chromosome haplogroup formerly known as J1c3 is now designated as J-P58 or J1a-P58, after the P58 SNP marker that defines it (source).
Under the older hierarchical notation, names like J1c3 were frequently renamed when new subclade structures were identified, and therefore "shorthand" designations based on the most characteristic and stable SNP that defines a haplogroup are now recommended. For example, an older name for this same haplogroup is J1e. The haplogroup was also sometimes formerly known as J1c3-L147, but J-P58, J1-P58, or J1a-P58 are currently preferred designations.