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The Ādam Paradox Hypothesis
Part III — The Threshold of Adam
57
Chapter 8
Genomic Switches as Candidates
FOXP2, HAR1, and SRGAP2C: regulatory loci that shaped the prepared
genome and set the stage for symbolic ignition
Introduction: From Threshold to Switches
In the previous chapter we confronted the paradox of the Threshold of
Adam: anatomically modern humans had brains like ours more than 150,000
years before they produced continuous symbolic culture. Fossils from Jebel
Irhoud (~315kya), Omo Kibish (~195kya), and Herto (~160kya) all show
cranial forms consistent with modern Homo sapiens (Hublin et al., 2017;
Rightmire, 2004). Yet for over 100,000 years the archaeological record
remained nearly silent, broken only by occasional sparks: an ochre engraving
here, a shell bead there.
If the hardware was ready, why did cognition remain dormant? The answer lies
not in anatomy but in genomic regulation. Developmental programs are not
driven only by raw DNA but by switches that orchestrate when, where, and
how genes are expressed.
Three loci stand out as icons of this preparatory phase:
FOXP2, the transcriptional conductor of vocal learning and motor
sequencing.
HAR1 and the broader Human-Accelerated Regions (HARs),
enhancers that whisper instructions during cortical development.
SRGAP2C, a duplication that slowed spine maturation and extended
childhood learning windows.
Each contributed to the refinement of a genome that was ready but not yet
activated. The Adam Paradox Hypothesis (APH) interprets these not as late
inventions but as long-laid preparations. The symbolic threshold was the
moment when these switches, long embedded in the genome, were finally
aligned and fired—turning capacity into continuity.