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:
Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University
How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy