The central dogma of molecular biology is that DNA makes RNA makes protein. This relies on a specific underlying code which relates given triplets of RNA nucleotides into specific amino acids. Each of the 20 amino acids is represented by one or more RNA triplets, or codons: UAC is decoded as tyrosine, for example, and UGC as cysteine. (U is the RNA nucleotide containing uracil, A is adenine, C is cytosine, and G is guanine.) For some time the code had been thought to be the same in all organisms. But exceptions have been seen before, particularly in mitochondria.
In a new study published online this week in the open-access journal PLoS Biology, Federico Abascal, Rafael Zardoya, and colleagues show that in the mitochondria of arthropod there are two nonstandard codes, and suggest that genetic code changes within a lineage may be more frequent than was earlier believed.
The authors aligned the mitochondrial coding sequence from >600 animal species looking for conserved codons and identifying which amino acid (AA) it specified in the corresponding protein. The most frequent AA was taken to be the canonical translation of that codon. What they found was that although most codons adhered to the common genetic code in all species, there was nonetheless a surprising trend in the arthropods, the largest of all animal phyla. Typically, AGG translates as the amino acid serine. However, among the arthropod mitochondrial genomes, AGG coded for serine in some species and lysine in others. The authors’ analysis of the patterns of change also suggests that the original arthropod mitochondrion used AGG for lysine, not serine.
The observed variety suggests the code has changed multiple times between the two genetic codes. It might be that pairing of AGG and lysine is disadvantageous for the organism employing it, so that loss or reversion over time would be favored. This might also suggest the existence of multiple other nonstandard codes within other lineages. Who knows what other alternatives might be decoded with this method in the future.
Citation: Abascal F, Posada D, Knight RD, Zardoya R (2006) Parallel evolution of the genetic code in arthropod mitochondrial genomes. PLoS Biol 4(5): e127.CONTACT:
Seeing on the Quick: New Insights into Active Vision in the Brain
15.08.2018 | Eberhard Karls Universität Tübingen
New Approach to Treating Chronic Itch
15.08.2018 | Universität Zürich
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
08.08.2018 | Event News
27.07.2018 | Event News
25.07.2018 | Event News
15.08.2018 | Physics and Astronomy
15.08.2018 | Earth Sciences
15.08.2018 | Physics and Astronomy