Wild animals that are directly visible in their environment are the main attraction for nature lovers. Most people do not know about the existence of a fascinating hidden world of animals that inhabit marine sand. This sand can host an impressive abundance and diversity of microscopic animals known as “meiofauna.”
These meiofauna are not only a key part of life's food chain and fundamental to keeping sediment clean, but they can also be used to address important questions in evolutionary ecology. For instance, how and why are there so many diverse species on Earth? How do they evolve in relation to time and different ecological conditions? How do geographical and geological barriers affect gene flow among populations?
These questions can potentially be answered by investigating the genomic diversity present in a small quantity of sand. Genotypes are correlated to the ecological conditions and geological histories of the environment. They can be used to infer the evolutionary origin of the group, and to infer how these organisms relate to each other; they are important to consider in existing general models of evolutionary ecology. Unfortunately, the genomes of meiofauna are poorly known. Our lack of knowledge is mostly because it is very difficult to identify these animals. It requires trained taxonomists spending several hours sitting at the microscope.
I am Francesca, a Buck Global Genome Initiative (GGI) fellow interested in investigating the genomes of meiofauna and how their levels of diversity change through time. I aim to compare the genomes of species that have been separated by known geological events, such as the raising of the Panama Isthmus, and identify genetic markers that reflect environmental changes.
Working on very tiny animals, which also lack published genomes, is very tough. I spent part of my research learning genomics techniques and data analysis at Hubbard Center of Genome Studies at the University of New Hampshire, in Durham, under the guidance of Prof. W. Kelley Thomas and his staff. The collaboration among different research groups is always inspiring and exciting. Despite the challenges these organisms pose, we succeeded in retrieving the genomes of several species from the phyla Annelida, Nematoda, and Nemertea.
Our preliminary and exciting results encouraged me to increase the number of species I will look at and the number of places I hope to find them, as well as to increase our knowledge about the genomic information of these microscopic organisms. With these goals in mind, I organized an international workshop in Panama by inviting several specialists from Europe, South and Central America, and the US to collect, identify, and preserve meiofauna.
We focused on the still unexplored Pacific side of Panama, namely Azuero Peninsula and Iguana Island, sampling from 0 to 20 meters depth. The meiofauna laboratory was located at the Achotines Lab facility. About 2,000 specimens belonging to at least 10 phyla, tens of families, and hundreds of morphological species were collected. A digital image was made from each one, and they are now stored at the NMNH Biorepository with the aim to preserve and investigate their genomes. The workshop, funded by 2015 GGI Awards, was very successful in increasing the knowledge of this hidden and important ecosystem and preserving their genomes for future fundamental evolutionary ecological questions.
By Francesca Leasi, Buck-GGI Postdoctoral Fellow, NMNH.