Chordodes horse hairworms utilize mantids as definitive hosts. After growing in the mantids, they control their hosts to get in water bodies where the parasites reproduce. Credit: Takuya Sato
Previous studies have recommended that horsehair worms hijack their hosts biological pathways and increase movement toward light, which leads the hosts to method water. Scientists believe this is achieved with particles that imitate those of the hosts central worried systems, but exactly how these parasites developed this kind of molecular mimicry has remained a mystery.
Gene Expression and Host Manipulation
To address this concern, the scientists analyzed whole-body gene expression in a Chordodes horsehair worm in the past, during, and after controling its mantis host. They found over 3,000 hairworm genes that were expressed more when hosts were being controlled, and 1,500 hairworm genes that were expressed less. On the other hand, gene expression in the mantis brains did not alter, and in reality, might not be identified from that found in uninfected mantises. These results show that horsehair worms produce their own proteins for manipulating their hosts nerve systems.
The scientists next searched a protein database to explore the origins of the genes that Chordodes horsehair worms use to control mantises. “Strikingly, many of the horsehair worm genes that could play important functions in controling their hosts were extremely comparable to mantid genes, suggesting that they were obtained through horizontal gene transfer,” says Mishina. Horizontal gene transfer is a biological process in which genes are moved from one organism to another, but not through recreation. It can have substantial evolutionary effects, permitting organisms to get new genes or functions rapidly, possibly helping them adapt to brand-new environments or lifestyles.
Molecular Mimicry and Evolution
Additional analysis supported the idea that the molecular mimicry seen in the Chordodes horsehair worms is most likely the result of horizontal gene transfer from mantises. In specific, over 1,400 Chordodes horsehair worm genes were discovered to match those in mantises, however were really different or missing from species of horsehair worms that do not utilize mantis hosts. The authors conclude that the numerous mimicry genes that they identified are most likely the result of several horizontal gene-transfer events from different mantid types throughout the advancement of hairworms. These genes, especially those related to neuromodulation, tourist attraction to light, and circadian rhythms, appear to play a function in host control.
Mishina thinks that as we find more examples of horizontal gene transfer in between multicellular organisms, we will get insight into this phenomenon as well as development in general. “Using this model, we hope to determine the systems underlying horizontal gene transfer and advance our understanding of evolutionary adaptation.”
Reference: “Massive horizontal gene transfer and the development of nematomorph-driven behavioral manipulation of mantids” by Tappei Mishina, Ming-Chung Chiu, Yasuyuki Hashiguchi, Sayumi Oishi, Atsunari Sasaki, Ryuichi Okada, Hironobu Uchiyama, Takeshi Sasaki, Midori Sakura, Hirohiko Takeshima and Takuya Sato, 19 October 2023, Current Biology.DOI: 10.1016/ j.cub.2023.09.052.
Scientist found that horsehair worms control their insect hosts utilizing genes acquired from the hosts themselves, shedding light on the role of horizontal gene transfer in advancement.
A team led by Tappei Mishina at the RIKEN Center for Biosystems Dynamics Research (BDR) has found that parasites manipulate their hosts utilizing stolen genes that they likely acquired through a phenomenon called horizontal gene transfer. The findings were recently released in the journal Current Biology.
Parasites and Host Behavior
Numerous parasites control the habits of their hosts to ensure their survival and capability to replicate. Horsehair worms show among the most sophisticated examples of this type of control of habits. Horsehair worms are born in water and use aquatic bugs like mayflies to hitchhike to dry land, where they stand by up until they are consumed by terrestrial bugs such as crickets or mantises.
As soon as a horsehair worm reaches these hosts, it starts growing and controls the hosts behavior. The grown horsehair worm finally causes the host to leap into water, often to the hosts supreme demise, so it can finish its life objective and replicate.
They discovered over 3,000 hairworm genes that were expressed more when hosts were being controlled, and 1,500 hairworm genes that were revealed less. “Strikingly, many of the horsehair worm genes that could play crucial functions in manipulating their hosts were very comparable to mantid genes, recommending that they were obtained through horizontal gene transfer,” says Mishina. Horizontal gene transfer is a biological procedure in which genes are moved from one organism to another, however not through reproduction. In specific, over 1,400 Chordodes horsehair worm genes were found to match those in mantises, however were very different or missing from types of horsehair worms that do not use mantis hosts. These genes, especially those associated with neuromodulation, destination to light, and circadian rhythms, appear to play a function in host control.