Diversity of asexual and anhydrobiotic nematodes in extreme environments

Some of his work has recently had a major impact, with nematodes awakening from their 'sleep' after 46,000 years in the Siberian permafrost:
https://www.sciencesetavenir.fr/animaux/deux-vers-nematodes-sortent-de-46-000-ans-de-sommeil_173277

https://www.scientificamerican.com/article/46-000-year-old-worm-possibly-revived-from-siberian-permafrost/

https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1010798

Abstract :

Deserts are among the most hostile environments to life on earth. Yet, some animals have adapted to survive and diversify in such extreme water limited environments. Evolutionary strategies for this include parthenogenesis enabling the exploration of transient ecological opportunities by offspring of a single individual, and cryptobiosis enabling organisms to wait for abiotic conditions to become favourable. Using biodiversity genomic assays with latest sequencing methods it is now possible to study genomes of single minute invertebrates, as well as population structures in many samples from extreme environments to understand the evolutionary strategies of different species.
Here, I will present our genomic, population genetic, and ecological functional analyses of the linked evolution of these traits in nematodes from the hyper arid Atacama in comparison with the younger, more dynamic Namib desert. We find locally diverse species assemblages. In accordance with evolutionary theory these are dominated by sexual species, but heterozygosity through polyploidy appears provide an adaptive advantage to parthenogens. We observe species to employ anhydrobiosis, a mode of cryptobiosis, in different ways, to either revive fast or more slowly upon water availability. We also recently assembled the genome of a triploid parthenogenetic Panagrolaimus revived from  another extreme environment, the Russian permafrost. Analysing it genetically and biochemically in comparison to C. elegans we find resemblances in the genetic mechanisms the model organism’s dauer larva and this nematode use for prolonged dormancy. Using the CRISPR/Cas system we are now able to study cryptobiosis in Panagrolaimus, allowing us to understand this trait on a genetic level comparing species from different extreme environments.

The conference can also be followed on Zoom at the link below:

https://inrae-fr.zoom.us/j/5785660130