Plants are often overlooked by animal biologists, liverworts are often overlooked by plant scientists, and Riccia has so far been overlooked by scientists that study liverworts, but these tiny plants form a genus with hundreds of species, many of which occur naturally within Australia, so for the curious mind their genomes could hold myriad trinkets and treasures.
What we’ve done so far - taking advantage of the wet winter of 2022 we have collected dozens of Riccia sp. from across Australia and are currently cultivating them in our lab, learning how best to make them grow.
What we plan to do next - systematically sequence the genomes/transcriptomes of these Riccia to assemble a trove of data with many potential applications in comparative and evolutionary genomics.
What we think we might discover - this project began with an interest in sex chromosome evolution [1], as multiple independent evolutionary transitions between monoicy and dioicy have occurred within Riccia, therefore uncovering the pattern of gene retention and loss in these diverse species will deepen our insights into genetic constraints on sex chromosome evolution.
However, after seeking out and taking multiple Riccia sp. into our care, our ambition for studying Riccia has continued to grow. For example, a few plants that we collected appear to belong to the same species but are actually paraphyletic [2], suggesting strong convergent selection which should be detectable in their genomes. Furthermore, better sequence data for some of these plants could help to define new species and better resolve the Riccia phylogeny. Divergent evolution can also be studied as Riccia species have evolved to inhabit both arid and aquatic environments [2]. Also, each species is likely to produce many interesting secondary metabolites, with unique tweaks to biosynthesis pathways producing currently undescribed compounds. Another unknown is the genetics underpinning diversity of spore size, spore coat geometry and spore germination requirements, with parallel unknowns in the ecology of spore dispersal and spore dormancy.
In summary, we are about to unravel a genetic treasure map full of Xs, and soon it will be time to start digging. Wish us luck!