U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights

Microbes Disprove Long-Held Assumption that All Organisms Share a Common Vocabulary
Published: May 23, 2014
Posted: August 20, 2014

Four letters—A, C, G, and T—make up the DNA bases in all organisms on Earth. The particular order, or sequence, of these same four letters genetically defines an organism and is a main reason that determining the genome sequence is now a foundational starting point for many biological investigations. Within this sequence are shorter, three-letter groups called codons that represent amino acids, the building blocks of proteins that carry out the myriad functions critical to life and biology. There are 64 of these codons and, routinely, 61 of them code for the 20 known amino acids. Three of these triplets function as stop signals and are used to mark the end of protein generation. Given that all organisms have genomes built on the same four letters, scientists had long assumed that they also all shared the same vocabulary and the 64 codons would be interpreted the same way across the board. However, a recent study from the U.S. Department of Energy’s (DOE) Joint Genome Institute (JGI) shows that for some organisms the instructions for these three codons mean anything but stop. The researchers focused on uncultivated microbes, whose genomes had been described through single-cell genomics and metagenomics, and on a collection of viral sequences. Nearly six trillion bases of sequence data were analyzed from 1,776 samples collected from the human body and several sites around the world. The study found that these stop codons often were reassigned to code for amino acids. This work builds on a previous study in which DOE JGI researchers successfully employed single-cell genomics to shed insight on a plethora of microbes representing 29 “mostly uncharted” branches on the tree of life.

Reference: Ivanova, N., et al. 2014. “Stop Codon Reassignments in the Wild,” Science 344, 909–13. DOI:10.1126/science.1250691. (Reference link)

Contact: Dan Drell, SC-23.2, (301) 903-4742
Topic Areas:

  • Research Area: Genomic Analysis and Systems Biology
  • Research Area: Microbes and Communities
  • Research Area: DOE Joint Genome Institute (JGI)

Division: SC-23.2 Biological Systems Science Division, BER


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)