Bob Goldstein, UNC Chapel Hill

TARDIGRADE – EVOLUTION OF BODY FORMS AND SURVIVAL OF EXTREMES

We have developed the tardigrade Hypsibius exemplaris as a new model for understanding how body forms evolve by changes to development, using Drosophila and C. elegans as reference models, and for understanding how biological materials can survive extreme conditions.

The Question(s)

The tardigrade Hypsibius exemplaris is a close relative of arthropods and nematodes, leaving it well placed for comparative biology using both Drosophila and C. elegans as reference systems for comparisons. Tardigrades survive conditions that most life cannot survive — conditions including desiccation, freezing to below 1 Kelvin or heating to above 100 degrees C in the desiccated state, extremes of radiation in both desiccated and hydrated states, the the vacuum of space — suggesting that tardigrades must produce protectants that can permit life to survive extremes. We and other labs have begun to identify tardigrade protectants and to begin to understand how the protectants work.

The Model

Hypsibius exemplaris can be cultured in the lab, and it has a short, 12-day generation time. Stocks of animals can be stored frozen and revived. The animals and their embryos are optically clear at all stages.We have developed protocols for immunostaining, in situ hybridization, microinjection of animals, and RNA interference. Yoshida et al. (2017) published the best current genome assembly, and RNA-seq data has been published for resistant and hydrated forms, and for many stages of embryogenesis.