Rhinolophus sinicus limb embryonic development single cell transcriptome

Bats are the only mammals capable of true flight, possessing unique wings primarily composed of elongated digits and interdigital membranes. However, the developmental coordination between digit elongation and interdigital membrane expansion remains poorly understood. Here, we conduct a single-cell analysis of developing bat limbs of Chinese horseshoe bat and for key development stages of limb. Within the sequenced 30 thousand cells, we identify a specific population of mesenchymal progenitors in the bat forelimb that express high levels of PDGFD. This cell population has the potential to differentiate into the interdigital membrane and release growth factors that promote the proliferation of bone-related cells. Compared to hindlimbs, the developing bat forelimbs undergo prolonged chondrogenesis and delayed osteogenesis, resulting in more chondrocytes and fewer osteoblasts. The bone-related cells also can release growth factors that facilitate the proliferation of skin-related cells. Our findings suggest that interactions mediated by growth factors among different cell populations play a vital role in coordinating the development of digit elongation and interdigital membrane expansion in bat forelimbs.