Which animal's genome revealed it can survive complete desiccation by replacing water with sugar?

The tardigrade, which expels almost all its water, curls into a barrel called a tun, and shuts down measurable metabolism entirely - specimens have been revived after decades. It is often billed as surviving vacuum, radiation and extreme cold, and the important qualification is that it survives them in this state rather than living through them.

The sugar story is partly wrong, and the correction is more interesting. Trehalose does the job in many desiccation-tolerant organisms, replacing water in a glassy matrix that holds membranes and proteins in shape - but several tardigrade species have almost none of it. What they have instead is a family of intrinsically disordered proteins, floppy and structureless in solution, which vitrify as the animal dries and do the same protective work. Put those genes in yeast or bacteria and they become desiccation-tolerant too.

A 2016 genome paper also reported that a sixth of tardigrade DNA had been acquired from bacteria by horizontal transfer, which made headlines and turned out to be contamination in the sample; a second group sequencing the same species found a normal figure. The radiation tolerance is real and appears to be a side effect - the same machinery that protects a drying cell protects against the DNA damage radiation causes.