SCITECH | Ancient retrovirus played key role in vertebral brain development through myelin formation
By Jay Adrian Lotivio
Scientists solved the mystery of the mechanisms that triggered myelination in the vertebrate tree of life, as a study published in Cell last February revealed that genetic elements from an ancient retrovirus facilitated the expression of myelin basic protein, a key component of myelin.
The mystery comes as myelin appeared at the same time with jaws, present in Chondrichthyes or jawed fishes, but the molecular reasons for its appearance eluded scientists. Dubbed “RetroMyelin,” scientists found the genetic element after studying the role of retrotransposons — non-coding regions that comprise 40% of our genomes — in myelination, something the study says has not been explored yet in the context of myelin biology.
Myelin is a tissue that ensheaths vertebrate nerve axons. Myelin’s ability to facilitate conduction of nerve impulses allowed for vertebrates to attain larger sizes and more complex brains without the need to increase the diameters of their axons. If nerves did not have myelin, the human spinal cord would need to have been as large as a tree trunk for the human body to still function at the same capacity.
Other than this, the study also reported that RetroMyelin was acquired multiple times through convergent evolution, highlighting the greater need for quicker axon conduction; faster conduction means you can do things much faster: run, kill, etc.
Read the full study by Ghosh et al. (2024) here: https://www.cell.com/cell/fulltext/S0092-8674(24)00013-8?
