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Evolutionary instability drives structural diversity and disease susceptibility at the 16p12.2 locus
Corrine Smolen1,2, Santhosh Girirajan1,2,3
1Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA.
Biorxiv : the Preprint Server for Biology
|March 23, 2026
Summary
Chromosome 16p12.2 exhibits significant structural variation and instability in humans due to extensive duplications. This genetic diversity influences susceptibility to neurodevelopmental disorders.
Area of Science:
- Genetics
- Evolutionary Biology
- Genomics
Background:
- The African great ape lineage shows extensive duplication, causing instability in chromosome 16p.
- The 16p12.2 locus is a region prone to structural variations and associated with neurodevelopmental disorders.
Purpose of the Study:
- To investigate the sequence structure and evolutionary history of the 16p12.2 locus.
- To understand the genetic mechanisms driving structural diversity and deletion susceptibility at this locus.
Main Methods:
- Examined sequence structure and evolutionary history of the 16p12.2 locus in 570 human haplotypes and seven non-human primates.
- Identified segmental duplication (SD) blocks, analyzed duplicon architecture, and traced inversions over evolutionary time.
Main Results:
- Human haplotypes at 16p12.2 display significant size variation and ancestry-biased structure, with 21 unique configurations arising from three SD blocks.
- Two specific duplicons (D5 and D6) within SDs are implicated in the 16p12.1 deletion associated with neurodevelopmental disorders, with varying breakpoint positions.
- The region has undergone numerous inversions (32 in humans) mediated by duplicons, with evidence of incomplete lineage sorting, interlocus gene conversion, and human-specific expansions of D5 and D6.
Conclusions:
- The 16p12.2 locus is characterized by evolutionary instability, driven by extensive segmental duplications and inversions.
- Structural diversity at 16p12.2 contributes to its susceptibility to deletions linked with human neurodevelopmental disorders.
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