Genetics: ‘Living fossil’ provides insight into arthropod evolution

The draft genome sequence of Mesobuthus martensii, a species of scorpion common to eastern Asia, is reported this week in Nature Communications. The genome highlights genetic features of the scorpion associated with its prey, nocturnal behaviour, feeding, and detoxification and provides a valuable resource for studying the adaptation and evolution of arthropods.

Scorpions are known as ‘living fossils’ and represent a unique type of arthropod because they maintain the primary anatomical features of their ancient arthropod ancestors. They therefore provide a key model for studying evolution in this group of animals. Wenxin Li and colleagues sequenced the first scorpion genome in order to explore the genes that are likely to be responsible for their long-term survival.

The team identify 32,016 protein-coding genes and provide evidence for the evolution of genes involved in the regulation of key survival mechanisms, which include venom production, the ability to respond to light and the digestion of harmful toxins from their prey. They suggest that while scorpions have undergone fewer physiological and morphological changes than insects, their genetic landscape may be far more diverse. These results could challenge the common belief that scorpions evolved more conservatively than insects and provide a unique adaptation model for arthropods.