Kaue's Way of Life
What do you have in common with your grandparents, aunts, uncles, half-siblings, nieces, nephews, and grandchildren?
The answer is 25% of your DNA.
When mapping out our family trees, it is fascinating to see exactly how our genetics are distributed across generations. The mathematical rule of thumb is simple: with every step away from you in the family tree, the amount of shared DNA roughly cuts in half.
Here is a breakdown of the expected percentage of shared genes across different generations of your family.
| Generation | 100% | 50% | 25% | 12.5% | 6.25% |
|---|---|---|---|---|---|
| -4 | Great-Great-Grandparents | ||||
| -3 | Great-Grandparents | Great-Great-Aunts/Uncles | |||
| -2 | Grandparents | Great-Aunts/Uncles | Half-Great-Aunts/Uncles | ||
| -1 | Parents | Aunts / Uncles | Half-Aunts/Uncles | 1st Cousins Once Removed (Up)* | |
| 0 (You) | You / Identical Twin | Full Siblings | Half-Siblings | First Cousins | Half-First Cousins |
| +1 | Children | Nieces / Nephews | Half-Nieces/Nephews | 1st Cousins Once Removed (Down)* | |
| +2 | Grandchildren | Great-Nieces/Nephews | Half-Great-Nieces/Nephews | ||
| +3 | Great-Grandchildren | Great-Great-Nieces/Nephews | |||
| +4 | Great-Great-Grandchildren |
(Note: “Up” refers to your parents’ first cousins. “Down” refers to your first cousins’ children.)
0 is your generation. Negative numbers (-1, -2) point to your ancestors and their peers, while positive numbers (+1, +2) point to descendants.It is important to remember that aside from the 50% you share with your parents and children, these percentages are expected averages.
Because of a biological process called recombination, the exact amount of DNA you inherit from specific ancestors is rarely a perfect mathematical split. For example, while you are expected to share 25% of your DNA with a grandparent, you might actually share 23% with one and 27% with another. However, the matrix above provides a highly accurate framework for understanding your genetic relationships.
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Updated on 2026 Oct 11.
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