Heritable differences in synaptic zinc-transporter levels drive variation in learned birdsong

Complex learned behaviors exhibit striking variation within populations, yet how heritable factors contribute to such inter-individual differences remains largely unknown. Here, we used behavioral-genetic analysis within a Bengalese finch population (Lonchura striata domestica) to investigate molecular and circuit mechanisms underlying heritable differences in the tempo of learned birdsong. We identified a genomic locus encoding the zinc transporter ZIP11 and found that zip11(SLC39A11) transcript was expressed at higher levels in song control circuitry of faster singing birds. Reducing soluble zinc increased synaptic currents in motor circuitry and accelerated song, whereas reducing ZIP11 slowed song. Our results reveal a novel zinc-dependent mechanism that modulates neural activity to drive differences in behavior and suggest that natural variation in learning may preferentially target modulatory processes rather than core neural machinery.