Unraveling the hidden secrets of the evolution of camel spiders with a modern gene tree

In a new study led by the laboratories of Prof. Prashant Sharma of the University of Wisconsin-Madison, and Dr. Efrat Gavish-Regev of the Hebrew University of Jerusalem, a team of researchers has discovered the mysteries surrounding camel spiders (Solifugae), successfully establishing the first comprehensive molecular tree (phylogeny) of this mysterious arachnid order.

Their results, based on the technique of primary sequence alignment (UCE) and a novel data set, provided valuable information on the evolutionary history and relationships of camel spiders. The study, titled “No more care: Phylogenomic resolution of high-order relationships in Solifugae” was published in the journal. Science.

Camel spiders, often referred to as the “neglected arachnid cousins,” have long been the subject of interest because of their remarkable traits such as aggression, exceptional running speed, and adaptation to arid environments. Despite their popularity, the lack of a high-resolution phylogeny has left many unanswered questions about the evolutionary history of these fascinating creatures.

In the past, it was difficult to study camel spiders because we could not easily distinguish them based on their phenotype. Until recently, the phylogeny of only one of the 12 recent families of camel spiders was studied using their genes (the parts of their cells that carry information), mainly because many historical specimens are kept for decades in collections around the world under conditions. which damaged their DNA, rendering them useless for genomic studies.

But now, Prof. Sharma, Dr. Gavish-Regev and their colleagues have used advanced techniques to look at specific parts of the genome that are conserved across all camel spiders, and surrounding regions that have changed during evolution. Led by Dr. Siddharth Kulkarni, a postdoctoral researcher at Madison, the novel method they are using can take advantage of historical material and increase fragmented DNA in genetic analysis. This allowed them to learn more about all the different families of camel spiders and their relationships to each other.

This research helped create a detailed high-level tree of camel spiders, showing how they are related to each other through evolution. Researchers have found that there are two main groups of camel spiders in the Americas, and they are part of a larger group of camel spiders that first appeared in tropical regions long ago.

By looking at ancient evidence, such as fossils, the team found that camel spiders first appeared around 250-300 million years ago during the Permian period. Most of these families of camel spiders had already diverged from each other before the great extinction event about 66 million years ago, in which many species, including the dinosaurs, disappeared. This shows that the breakup of the continents had a major impact on how camel spiders evolved.

The study made an important discovery in how we distinguish between camel spiders. The researchers proposed two new groups: one of the camel spiders from Laurasia (north of the equator) called Boreosolifugae and those from Gondwana (south of the equator) called Australosolifugae. They have good reasons for doing this based on the physical characteristics of these arachnids and where they live. This discovery is important because it changes the way we organize and understand camel spiders in the big picture of their high-level tree.

Dr. Efrat Gavish-Regev said, “Our work has finally brought camel spiders out of the shadows and illuminated the phylogenomic analysis. Now we have a better picture of their evolutionary history and relationships, and our proposed suborders provide a solid framework for future research in this interesting area.” ”

This study not only fills an important gap in understanding arachnid evolution but also demonstrates the power of modern genomic methods in unraveling the mysteries of complex organisms living in challenging environments. The results are poised to encourage further research on Solifugae and deepen our appreciation of the diversity of life on our planet.