# Molecular development of chondrichthyan claspers and the evolution of copulatory organs

Article · O'Shaughnessy KL, Dahn RD, Cohn MJ

- Archive id: doi:10.1038/ncomms7698
- Published: 2015-04-14
- Venue: Nature communications
- DOI: https://doi.org/10.1038/ncomms7698
- PMID: 25868783
- PMCID: PMC4403318
- Citations: 31
- Source URL: https://doi.org/10.1038/ncomms7698
- PDF: https://europepmc.org/articles/PMC4403318/pdf
- Provenance: europepmc

## Abstract

The earliest known vertebrate copulatory organs are claspers, paired penis-like structures that are associated with evolution of internal fertilization and viviparity in Devonian placoderms. Today, only male chondrichthyans possess claspers, which extend from posterior pelvic fins and function as intromittent organs. Here we report that clasper development from pelvic fins of male skates is controlled by hormonal regulation of the Sonic hedgehog (Shh) pathway. We show that Shh signalling is necessary for male clasper development and is sufficient to induce clasper cartilages in females. Androgen receptor (AR) controls the male-specific pattern of Shh in pelvic fins by regulation of Hand2. We identify an androgen response element (ARE) in the Hand2 locus and present biochemical evidence that AR can directly bind the Hand2 ARE. Together, our results suggest that the genetic circuit for appendage development evolved an androgen regulatory input, which prolonged signalling activity and drove clasper skeletogenesis in male fins.

_Abstract reproduced under CC-BY (article license as recorded by Europe PMC; abstract reproduced unmodified apart from markup removal)._

Topics: [Synthetic Biology & Genome Engineering](https://space-kitty.com/topics/synthetic-biology)

---
Space Kitty Archive · https://space-kitty.com · API: https://space-kitty.com/api/v1 · MCP: https://space-kitty.com/mcp · Premium: $0.20/request via x402 (Base Sepolia (testnet)). Metadata: arXiv (CC0), OpenAlex (CC0), Europe PMC (CC BY/CC0 works), ClinicalTrials.gov.