Exploring the Black Box of Marine Microbial Eukaryotes  

Marine microbial eukaryotes are microscopic organisms that inhabit virtually all ocean ecosystems. While they play critical roles in marine food webs and elemental cycles through photosynthesis, predation, serving as prey, and in some cases parasitizing other organisms, little is known about their genes because their genomes can be very large and structurally complex. Some genomes from this incredibly diverse group of microorganisms are in fact much larger than a human’s, even though they are single-celled creatures.  

There are only about a dozen completed genome sequences of marine microbial eukaryotes, and transcriptome studies—sequencing the molecules that reflect what genes are being used by an organism at any given time—have been restricted to a small number of species. Attempting to sequence large eukaryotic genomes can be time-consuming, costly, and not guaranteed to succeed, while transcriptome sequencing can provide an alternate method for obtaining gene content information.  

The Marine Microbial Eukaryote Transcriptome Sequencing Project, supported through a Foundation grant to the National Center for Genome Resources, is helping the research community better understand the ecology and evolutionary relationships among these important organisms by looking at their gene expression patterns. A collaboration with nearly 80 scientists from the international community will sequence 750 transcriptomes from hundreds of diverse marine microeukaryotes.  

The sheer magnitude of the effort portends unexpected discoveries regarding how these organisms support the base of the ocean food web and removal of carbon dioxide from the atmosphere.