How Does Life Begin and Develop?
Objective
1
Sources of 0rganics on Earth
Objective
2
Origin of Life's Cellular Components
Objective
4
Genomic Clues to Evolution
Objective
5
Linking Planetary and Biological Evolution
Does Life Exist Elsewhere in the Universe?
Objective
7
The Extremes of Life
Objective
8
Past and Present Life on Mars
Objective
9
Life's Precursors and Habitats in the Outer Solar System
Objective
10
Natural Migration of Life
Objective
11
Origin of Habitable Planets
Objective
12
Effects of Climate and Geology on Habitability
Objective
13
Extrasolar Biomarkers
What is Life's Future on Earth
and Beyond?
Objective
14
Ecosystem Response to Rapid Environmental Change
Objective
15
Earth's Future Habitability
Objective
16
Bringing Life with Us beyond Earth
Objective
17
Planetary Protection
Question: How Does Life Begin
and Evolve?
Genomic Clues to Evolution
Objective 4: Expand and interpret the genomic database of a select group of key microorganisms in order to reveal the history and dynamics of evolution.
Modern computational techniques in genomics and bioinformatics give exciting new insights into biological structure and function at all levels. Using these increasingly sophisticated techniques, detailed studies of evolutionary dynamics at the genome level should be conducted, ultimately to allow the reconstruction of the development of genetic complexity through evolutionary relationships. Recognizing that simple mutation and selection are not the sole drivers for evolutionary change, we must define the roles of mechanisms such as gene transfers between organisms, and gene duplication and gene rearrangement within an organism. Using the large array of databases now available, we must extend studies of individual gene families to previously uncharacterized microbial species. These studies, along with phylogenetic studies of evolutionary orthologues for key metabolic and information-processing systems in living cells, comparisons of sequences from discrete evolutionary lineages, and evolutionary studies of complex gene families within a single genome, will help determine when and how key biological functions arose and spread.
Implementation
Near- and mid-term:
- Exploit the genomic databases
that are already available, studying them in order to infer sequences
of evolutionary steps and thus to estimate mechanisms (for example,
duplication vs. transfer of genes). Notable progress for eukaryotic
organisms can be expected using this approach.
- Expand the databases by instituting
a program of genomics focused on organisms representative of the metabolic
diversity found among the prokaryotes. Full closure, with complete coverage
of an organism's genome, is not required. Instead, information highly
useful for the goals of the Astrobiology program can be obtained from
the techniques of so-called "random genomics," in which accessible fragments
resulting from diverse cleavages are sequenced.
- Develop new information systems to organize and interpret molecular sequence data in order to determine the mechanisms, frequency, and impact of key molecular drivers of evolution.
Future Extensions:
- This effort will contribute to a model for the evolutionary dynamics of microbial genomes, with potential applications that range from a reconciliation of biomolecular records of early life with geologic records, and also to enabling revolutionary new vistas in bioengineering.