Comparative single-cell analyses reveal evolutionary repurposing of a conserved gene programme in bat wing...

Area of Science:

• Developmental Biology
• Evolutionary Biology
• Comparative Genomics

Background:

• Bats are unique flying mammals, with forelimbs adapted into wings featuring elongated digits and a chiropatagium membrane.
• Understanding the evolutionary origins of bat wings is crucial for insights into vertebrate limb development.

Purpose of the Study:

• To investigate the developmental and cellular origins of the bat wing structure.
• To compare bat and mouse limb development using advanced molecular techniques.

Main Methods:

• Utilized omics tools and single-cell RNA sequencing on embryonic bat and mouse limbs.
• Performed micro-dissection of embryonic chiropatagium for detailed cellular analysis.
• Employed transgenic mouse models for functional gene expression studies.

Main Results:

• Observed conservation of cell populations and gene expression patterns between bat and mouse limbs, including interdigital apoptosis.
• Identified a distinct fibroblast population within the embryonic chiropatagium as the source of the wing membrane.
• Discovered that MEIS2 and TBX3 transcription factors in distal limb cells activate wing development genes and influence digit morphology.

Conclusions:

• Bat wing development involves a specific fibroblast population, distinct from apoptosis-driven interdigital cell death.
• Repurposing of conserved gene regulatory networks, like those involving MEIS2 and TBX3, underlies the evolution of bat wing morphology.
• This study provides fundamental molecular insights into the evolution of flight in mammals.