Table 3.
Estimated amount of shared DNA given some biological relationships.
| Relationship with the sample | Percentage | cM (average) |
|---|---|---|
| Parent, child | 50% | 2376-3720 (3485) |
| Sibling | 50% | 1613-3488 (2613) |
| Grandparent/grandchild | 25% | 984-2462 (1754) |
| Uncle/aunt, niece/nephew | 25% | 1201-2282 (1741) |
| Great grandparent, great grandchild | 12.5% | 485-1486 (887) |
| 1st cousin | 12.5% | 396-1397 (866) |
| 2nd cousin | 3.125% | 41-592 (229) |
| 3rd cousin | 0.781% | 0-234 (73) |
| 4th cousin | 0.195% | 0-139 (35) |
Sources: B.T. Bettinger's shared cM Project version 4.0 [thegeneticgenealogist.com/2020/03/27/version-4-0-march-2020-update-to-the-shared-cm-project/]; and the International Society of Genetic Genealogy Wiki [isogg.org/wiki/Autosomal_DNA_statistics]. [last accessed 3 November 2023]