Mitochondrial haplogroups

Mitochondrial haplogroups are family branches of your mitochondrial DNA (mtDNA), which you inherit only from your mother. Each branch is defined by a shared set of DNA tweaks, and together they trace ancient human migrations. Because mtDNA carries the instructions for 13 key parts of the cell's energy machinery (plus 22 tRNAs), the small variants that define a haplogroup can subtly change how efficiently your cells make energy, how many reactive byproducts they throw off, and how the mitochondria are shaped. Some studies link specific haplogroups to long life, most famously the D4a and D5 branches in Japanese centenarians (Tanaka et al.) and the J branch in some European groups. But the findings do not replicate cleanly across populations, the early studies were small, and population differences muddy the picture. So haplogroups are plausible but unproven dials on the aging trajectory.

Last reviewed: June 22, 2026

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