Research in the Leys lab focuses on the evolution of animal characters
Sponges are widely considered the sister group to all other metazoans. They are not only important ecologically as they filter our oceans and lakes, but they are ultimately intriguing because they have lots of animal-like whole body behaviours without having a nervous system. Some work suggests that sponges might have lost neurons. Is that possible? We are studying sponge genomes, physiology and tissues - including sensory and contractile cells - in the adult and as they develop.

One hypothesis we are exploring is that  sponges are not just ‘almost animals’ (parazoa) but animals that are highly adapted to a suspension feeding lifestyle. Perhaps they became the ultimate suspension feeder by ‘losing’ aspects of more complex tissues, organization, and genes. 
Another hypothesis is that sponges are the only group of metazoans that has always functioned in a way independent of neurons and nervous systems. Understanding how sponges sense their environment and how the cells communicate to one another to coordinate whole animal behaviour is our major challenge.

CURRENT PROJECTS

Ephydatia muelleri genome resource and evo-devo questions

 Ephydatia muelleri  is a green or yellow sponge that is found in lakes and rivers throughout the northern hemisphere. We chose to sequence its genome because - among freshwater sponges - it has a couple of characteristics that are very practical. First it has been studied in Japan, Europe, and North America, for several decades. Its gemmules are robust and tolerate freezing to -80C meaning we can ship them across continents for others to work on. It can be easily cultured in the lab and each gemmule is a clone of the adult sponge, meaning thousands of clones can be cultured from the same genotype.
And...it sneezes! What could be more cool than a sponge with no nervous system 'sneezing'? The sneeze can be triggered in the lab and so this behaviour is a very tractable system to study. 

Sensory cells

What is the evolutionary history of sensory cells in metazoans?
This project aims to understand the physiology, cytology and molecular biology of cells that receive information from the environment and transmit it to an effector. We are studying larval sponges as well as juvenile and adult sponges. This work involves video imaging of adult animals in their native habitat, lab work with larval cultures (also at field stations), molecular work to study genes expressed in particular tissues, and ultrastructure to understand the tissues and cell connections that underlie these behaviours.

Paleo-Eco-Evo-Devo!

What were the first animals like? What were early oceans like for light, phytoplankton, bacteria, oxygen? What did the first animals eat?
We have a rich set of fossils from the Burgess Shale which should reveal the lifestyle of the early Cambrian filter feeding fauna. By understanding the ecology of that fauna and other fossil sponge and ctenophore fauna we will have a better grasp of what was possible in those seas.

Vauxia (left) is a cool sponge that lived in what is now the Burgess Shale British Columbia. [See Pablo Aragones' project description]

Marine Protected Areas & Sponge Reefs

Glass sponges are stunning pillars of golden animals. They are silent in filtering thousands of liters of water - removing bacteria and other pico-plankton - for food, and excreting the wastes as CO2, ammonium, and particulates for others to use. They are a hugely important factor in recycling water, especially where large numbers exist. On the west coast of British Columbia glass sponges form vast reefs, some under the flight path into the Vancouver Airport. Why do reefs form where they do, why glass sponges live only in deep, cold, silica rich water? 
[See Nikita Sergeenko's project description]