chr14 · 14q13.1 · 260 nt · 2006

HAR2 / NPAS3

NPAS3 HAR cluster

Anomaly

6.34

Genes

NPAS3

Length

260 nt

What it is

NPAS3 is a brain transcription factor. The protein code is largely shared with other primates; the surrounding switches are not. Human-accelerated enhancers in and around NPAS3 likely change when and how strongly this factor is used during neurogenesis, which can shift intelligence-related traits and psychiatric risk together — a trade, not a destiny.

Why it matters

Largest HAR cluster; neurogenesis and psychiatric genetics.

Operator load

01 · ΔE
Enhancer activity
These stretches of DNA do not code for proteins. They act as volume knobs — turning nearby brain-development genes up or down at the right moment.
03 · T
Three-dimensional rewiring
The genome folds in 3D. Human-specific changes can re-route which switches sit next to which genes, even if the letters look similar in a straight line.
06 · P
Population spread
Once a change is useful, it spreads. Many HAR variants rose quickly in ancestral humans and are now nearly fixed across living populations.

Kamm et al. Mol Biol Evol 2013 · Pickard et al. 2005

Same neighborhood

HAR21 — A human-accelerated enhancer sitting inside NPAS3 itself — a switch embedded in the gene it helps control.
HAR202 — A human-accelerated enhancer sitting inside NPAS3. 2025 CRISPR work shows the human letters turn this gene down by changing which proteins can sit on the DNA.