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Environmental Genomes and Evolution of Complex Systems in Simple Organisms

The Marine Biological Laboratory Team employs molecular techniques to explore how relatively simple organisms and their genomes (compared to those of metazoans) evolved into more complex forms. Their astrobiology program goal is to search for novel eukaryote diversity in rarely studied environments, some resembling conditions possibly existing millions/billions of years ago on other solar system bodies.

Research concerns these general areas: (1) how multi-member gene families and entire genomes have evolved; (2) how evolution of the genotype is related to changes in the phenotype; (3) how processes other than simple mutation influence evolution of life on Earth (e.g., endosymbiosis and how microbial lineages have adapted to extreme environments); and (4) how eukaryotes originated and evolved into complex, multicellular forms. Research investigations span the levels of individual genes, genomes, cells, populations, communities, and entire ecosystems.

Eukaryotic Origins and Evolution of Cellular Complexity

A massive evolutionary expansion of eukaryotes occurred about 1 billion years ago, giving rise to plants, animals, fungi, and many other protist groups. Research projects investigate evolution of biological complexity to understand protist group diversity and phylogeny for all eukaryotes.

• Eukaryotic rRNA Evolution: Early Diverging Eukaryotes. Use molecular analyses of SSU (small subunit) ribosomal RNA genes of pelobiont microorganisms (eukaryote group) to determine their phylogenetic and evolutionary history.
• Evolution of Tubulins. Characterize tubulin genes from jakobid flagellate organisms to determine their phylogenies in relation to other early-diverging eukaryotic lineages.
• Eukaryotic rRNA Evolution: Origins of “Crown Group Taxa”. Study the branching pattern of selected taxa microorganisms using molecular sequence data (full length, large subunit rRNA sequences) to compile a data set for greater resolution in our phylogenetic inferences.

Diversity of Eukaryotes in Thermophilic and Mesophilic Environments Possibly Resembling Early Earth’s Biosphere

Characterize eukaryotic diversity in hydrothermal vent environments with phylogenetic analysis of 18S rRNA sequences of microbes in upper layer vent sediments (Guaymas Basin, Gulf of California), to survey biodiversity of extreme habitats on Earth and provide background for extraterrestrial biosphere hypotheses.

Diversity of Prokaryotes in Thermophilic and Mesophilic Environments Possibly Resembling Early Earth’s Biosphere

Analyze microbial communities in hydrothermal vent sediments (Guaymas Basin, Gulf of California) by 16S rRNA sequencing and 13C isotopic analysis of archaeal and bacterial lipids, to add to knowledge about conditions, life forms, and biodiversity of this ecosystem habitat.

Eukaryotic Diversity in the Rio Tinto: Spain’s Acidic/High Metal Extreme Environment

Characterize full-length, eukaryotic, small-subunit ribosomal RNA molecular samples from several Rio Tinto sampling stations (including the river source) with summary of results in a phylogenetic analysis, as a model for Mars life study.

Protist Diversity in Extreme Environments

Use cultures and genetic analysis to study protist organisms from deep-sea sediments of the Antarctic, an understudied ecosystem that may share characteristics with the deep ocean floor of Europa.

*Micro*scope: New Internet Resources for Microbial Biodiversity*

Continue development of a new website, entitled micro*scope (http://www.mbl.edu/microscope), an image-rich bioinformatics source to access and identify microbial diversity, which supports our investigations of biological complexity and expands our outreach program.

Genes That Regulate Photosymbiotic Interactions

Studies to determine genetic mechanisms behind photosymbiotic relationships of algae and how this may relate to evolution of organelles, all to provide insight about how eukaryotic life on Earth evolved.

Relationship of Genetic Changes to Phenotypic Changes in Organism – Environment Interactions

Investigate how genetic changes produce phenotypic changes: 1) use the genetic basis of spectral tuning in animal color vision as a model system; 2) determine peptide sequence variations and spectral tuning for vertebrate opsins, then for arthropod opsins; 3) complete these tasks in order to compare models across these broad taxonomic groups; and 4) utilize sequence analysis for linking phenotypic change with genotypic evolution.

Origin of Life: Evolution of Proteins

Explore the link between genotype and phenotype evolution through studies of related gene families in E. coli (biological functions of E. coli genes and gene products), in order to characterize its basic protein families and build implications for knowing the entirety of what is required to give life on early Earth.