Mark Q. Martindale and Yale Passamaneck from the Kewalo Marine Laboratory of the Pacific Biosciences Research Center at UH Mānoa have been awarded a four-year, $960,000 grant from the NASA Exobiology and Evolutionary Biology Program to study the evolution of increased cell-type complexity in “simple” marine animals. This program is a component of NASA’s Astrobiology Program that funds basic research focused on the origin and early evolution of living organisms, adaptation of organisms to different environments, and the implications for life elsewhere.
The researchers are studying the genomes of different animals. As embryos develop, cells differentiate into highly specialized cell-types that perform specific functions (e.g., nerve cells, muscle cells, gut cells or lung cells) through the expression of unique combinations of genes. Adult humans possess over 200 different kinds of cells, but marine animals have fewer different cell-types (e.g., 10-20).
One part of the project looks at the molecules in the opsin family of proteins that transduce light energy into chemical energy. In most animals, opsin molecules are located in a specialized cell-type called neural photoreceptor cells, located in the eyes. However, the research team recently found that, in a group of marine animals called brachiopods, these molecules are surprisingly expressed at very early stages in embryo development, even before eyes or any neural photoreceptor cells begin to form.
The researchers are also studying increased cell-type complexity that involves the sequenced genome of a sea anemone (see attached digital photo). Cnidarians such as sea anemones, corals and “jellyfish” have stinging cells called cnidocytes, which are not found in any other kind of animal. The grant will fund research to identify genes unique to sea anemones, and to determine if and how these new genes are involved in the formation of novel cell types.