10.6084/m9.figshare.9971633.v1
Natalie Turner
Natalie
Turner
Deimante Mikalauskaite
Deimante
Mikalauskaite
Krista Barone
Krista
Barone
Kathleen Flaherty
Kathleen
Flaherty
Gayani Senevirathne
Gayani
Senevirathne
Noritaka Adachi
Noritaka
Adachi
Neil H. Shubin
Neil H.
Shubin
Tetsuya Nakamura
Tetsuya
Nakamura
Supplementary text, figures and table from The evolutionary origins and diversity of the neuromuscular system of paired appendages in batoids
The Royal Society
2019
skate
fin
muscle
nerve
Hox
migratory muscle precursor
2019-10-11 16:18:56
Journal contribution
https://rs.figshare.com/articles/journal_contribution/Supplementary_text_figures_and_table_from_The_evolutionary_origins_and_diversity_of_the_neuromuscular_system_of_paired_appendages_in_batoids/9971633
Appendage patterning and evolution have been active areas of inquiry for the past two centuries. While most work has centred on the skeleton, particularly that of amniotes, the evolutionary origins and molecular underpinnings of the neuromuscular diversity of fish appendages have remained enigmatic. The fundamental pattern of segmentation in amniotes, for example, is that all muscle precursors and spinal nerves enter either the paired appendages or body wall at the same spinal level. The condition in finned vertebrates is not understood. To address this gap in knowledge, we investigated the development of muscles and nerves in unpaired and paired fins of skates and compared them to those of chain catsharks. During skate and shark embryogenesis, cell populations of muscle precursors and associated spinal nerves at the same axial level contribute to both appendages and body wall, perhaps representing an ancestral condition of gnathostome appendicular neuromuscular systems. Remarkably in skates, this neuromuscular bifurcation as well as colinear <i>Hox</i> expression extend posteriorly to pattern a broad paired fin domain. In addition, we identified migratory muscle precursors (MMPs), which are known to develop into paired appendage muscles with <i>Pax3</i> and <i>Lbx1</i> gene expression, in the dorsal fins of skates. Our results suggest that muscles of paired fins have evolved via redeployment of the genetic programme of MMPs that were already involved in dorsal fin development. Appendicular neuromuscular systems most likely have emerged as side branches of body wall neuromusculature and have been modified to adapt to distinct aquatic and terrestrial habitats.