To get a clear picture of this major evolutionary transition (the origin of multicellular animals), we first need to identify all of our closest living unicellular relatives, many of which remain hidden in the world's oceans and lakes.
Aim 1.
Our first goal was to create a comprehensive map of the unicellular organisms that are most closely related to animals and detect any unknown group. Since many of these microbes have never been seen, the best way to find them is to use DNA. We search for their genetic fingerprints—traces of their DNA—directly in water samples collected from the environment.
Our progress so far:
-By analyzing vast public databases of environmental DNA, we have confirmed the existence of eight completely new lineages of organisms that are close relatives of animals.
-We have mapped the global distribution of these mysterious lineages, creating a "treasure map" that tells us the best places on Earth to find them.
-We have designed "Holozoa-specific" primers for the 18S RRNA. These will be primer that will preferentialy amplify the organisms of interest in the PCR and not bilaterian animals or other major eukaryotic lineages. We have tested them and they seem to work fine.
-We have also designed specific primers for all the eight unknown lineages we have so far detected.
-Following our map, we have already conducted sampling expeditions in promising locations, including the Mediterranean Sea, the Atlantic coast of the Iberian Peninsula, and Lake Sanabria in Spain. We are currently extracting DNA and performing PCRs to sequence those samples using universal primers and specific primers for our organisms that take most metazoans out (to increase chances to get organisms of interest).
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Aim 2.
Finding an organism's DNA is one thing; growing it in the lab is another major challenge. To truly study these new life forms, we need to cultivate them.
Our progress so far:
-We have been working on a method to make these organisms glow with fluorescence, which would allow us to study them while they are alive. While this technique is still under development for these new cell types, we have successfully established an alternative method that lets us see their unique shapes and structures, even though it kills the cells. We believe this will help us “fish” these unknown lineages-
-Using FISH-CARD we have the first images of two lineages that were previosuly unknown.
-Indeed, our most exciting breakthrough has been the successful isolation and cultivation of a representative from a new lineage, known as MAOP-2. We now have a thriving culture of this organism. This culture is pure and ready for in-depth genetic sequencing.
Aim 3.
With a new organism successfully growing in our lab, we have now begun the final and most exciting phase of our project: getting to know our newfound relative.
Our progress so far:
-We are currently performing advanced microscopy and cell biology experiments on our first isolate, the MAOP-2 lineage. This is our first chance to observe the behavior and structure of an organism closely related to animals that, until now, was completely unknown to science. The insights from these first studies will pave the way for a deeper analysis of its genome and its unique place on the tree of life.
-we also got a transcriptome and a genome.
