Trigoniulus corallinus (left) and Helicorthomorpha holstii (right) are two millipede species that are commonly found in Hong Kong. T. corallinus can be easily be spotted on the ground after rain in the spring, while H. holstii can be commonly seen in farm soil, on hiking trails and elsewhere in the countryside in warm and humid seasons.

First myriapod genome bank explains divergent evolutionary trajectories

31 May 2022

Biologists at the Chinese University of Hong Kong have sequenced the entire genome of nine centipede and millipede species, resulting in the first myriapod gene repertoire analysis in the world.

Both centipedes and millipedes belong to a group of arthropods called myriapods. There are roughly 16,000 species of myriapods and they play an important ecological role in recycling nutrients in soil and forest ecosystems.

Led by Dr Jerome Hui at the School of Life Sciences of the Chinese University of Hong Kong, the research revealed several unexpected gene alternations that led to divergent behaviours of the two myriapod cousins and provided important insights into the genomic evolution of myriapods.

The findings were reported in Nature Communications.

“This remarkable divergence has led to two very different lifestyles being expressed in myriapods: predation in centipedes, characterised by the evolution of venom, and a detritivorous diet in millipedes. Our research provides the first steps towards unravelling the genomic bases of the divergent adaptations underlying these two lineages with very different ecologies,” Hui explained.

The team identified a number of potential factors that shaped the divergent evolutionary trajectories. Genetic gains in signal transduction were discovered in centipedes, which may have contributed to the sensory and locomotory adaptations that facilitated their ecological shift to predation. Apart from ecological features, the team also found that existing centipedes have retained key enzymes that produce sesquiterpenoid hormones from their myriapod ancestor, which are absent in millipedes.

“In addition to exploring the hidden biology and genomics of myriapods, we must further explore their ecological roles in soil and forest ecosystems. Hopefully one day we can gain a better understanding of these life forms, the effects that climate change may have on them, and their contribution to nutrient recycling,” added Hui.