A Scolopendra morsitans centipede. Credit: © Eivind Undheim
Centipede venoms include genes borrowed from bacteria and fungi, highlighting an unusual but impactful evolutionary strategy through horizontal gene transfer.
Venom expert Dr. Ronald Jenner from the Natural History Museum together with his colleague Dr. Eivind Undheim, who is associated with The University of Oslo and the Norwegian University of Science and Technology, have uncovered secrets of centipede venom.
As part of an ongoing, wider study into centipede venoms, the researchers set out to discover whether centipede venom toxins may have evolved elsewhere in the tree of life, in places other than their direct, arthropod ancestors.
Venom Genes Borrowed from Microbes
They soon unveiled that centipedes have repeatedly stocked their venoms with proteins that independently evolved within bacteria and fungi. The centipedes have acquired these toxin components through a process known as ‘horizontal gene transfer’.
Horizontal gene transfer is a process by which genetic material moves between distantly related organisms, in this case between bacteria and fungi, and centipedes. It is distinguished from the movement of genetic material from parents to offspring and from ancestors to direct descendants, which is known as vertical gene transfer.
Dr. Ronald Jenner, researcher in the Life Sciences department of the Natural History Museum said, ‘This discovery is remarkable. It reveals the largest, most diversely sourced contribution of horizontal gene transfer to the evolution of animal venom composition known to date.’
Many studies have been carried out into the venoms of various creatures: snakes, scorpions, and spiders, often because they are dangerous to humans. However, as centipedes are not dangerous to humans, their venoms have been neglected in terms of research. But interest is rising and the complex processes happening within centipede venom evolution show it is fertile ground for investigating phenomena such as horizontal gene transfer.
Bacterial Toxins Repurposed by Centipedes
As the team began to look at specific proteins within these centipede venoms they made some significant further discoveries. As Dr. Ronald Jenner explains, ‘three of the five venom protein families that centipedes have acquired by horizontal gene transfer are used by bacteria explicitly to exploit their hosts’, including by damaging their cells by the formation of pores.
They also noticed “three protein families were each horizontally transferred twice which shows that horizontal gene transfer is an unexpectedly important factor in the evolution of centipede venoms.” While the mechanisms behind horizontal gene transfer, especially from bacteria to animals, are not well understood, it is known to have contributed a range of adaptive benefits to different groups of animals.
The paper was published in Nature Communications.
Reference: “Phylogenetic analyses suggest centipede venom arsenals were repeatedly stocked by horizontal gene transfer” by Eivind A. B. Undheim and Ronald A. Jenner, 5 February 2021, Nature Communications.
DOI: 10.1038/s41467-021-21093-8
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