Fig. 1: RXFP2 only expressed in male and female antlerogenic periosteum.

A Schematic showing the locations of antlerogenic periosteum (AP), facial periosteum (FP), and long bone periosteum (LP) tissues. AP-m: male AP; AP-f: female AP. B Venn diagram depicting upregulated genes between AP-m vs. FP and AP-f vs. FP based on log₂Foldchange > 4 and adjusted p < 0.001. The 55 shared up-regulated genes are highlighted by a red dashed box, with RXFP2 specifically highlighted in red. C Immunoblots of RXFP2 protein in AP-m and AP-f tissues, with GAPDH as the internal reference protein. Relative intensity of each immunoblot was calculated using Image J. *p < 0.05. Error bars indicate the SEM. D Expression levels (FPKM) of RXFP2 across different deer tissues. Both AP-m and AP-f tissues are highlighted in red, and AP-derived tissues (pedicle periosteum and antler reserve mesenchyme) are highlighted in green. FPKM: Fragments per kilobase of transcript per million mapped fragments. E Expression levels (FPKM) of RXFP2 across three antlered deer species (sika deer, wapiti, and reindeer) compared to one antler-less deer species (CWD: Chinese water deer), with no detectable expression of RXFP2 observed in CWD. **p < 0.01. Error bars indicate the SEM.