Haplogroup I-BY128 is a Y-chromosome (paternal) haplogroup on TheYtree, catalogued with its defining mutations, sample distribution and phylogenetic tree.
| ISOGG name | I2a1a2b1a1a1a |
|---|---|
| Defining mutations | 124 |
| Downstream branches | 17 |
| Estimated age | 2,000 years |