Traditional DNA consists of four base pairs.A, C, G, and T. But the newly created genetic system is packaged in eight — twice as many as commonly found in self-replicating molecules. The new system is called "hatimoji", and what is most interesting is that it may be similar to the building blocks of extraterrestrial life, that is, aliens. A new study, published recently in Science, describes hatimoji, which means "eight letters" in Japanese.
In addition to the four base pairs, thisThe genetic system has four building blocks, which significantly increases the density of information compared to ordinary DNA. Scientists who have submitted the work say that the new system can be sufficiently reliable to support life — that is, to support the processes necessary for Darwinian self-reproduction.
Eight-letter alien DNA
Immediately make it clear that Hatimoji is not autonomous.self-sustaining organism. Rather, it is a model of an alternative genetic structure necessary to maintain a self-replicating life. On Earth, exclusively RNA and DNA perform this function, but this does not mean that other options in space cannot exist. In fact, astrobiologists are very interested in this research, because it demonstrates another possible mechanism from which life could emerge, evolve and encompass the complexities.
The authors of the study do not claim that hatimojiexists throughout the universe, but they believe that it is possible to take and “imagine parallel processes,” says Andrew Ellington, co-author of a new research and synthetic biologist from the University of Texas, Austin. "By carefully analyzing the roles of shape, size, and structure in the hachi-mmoji DNA, in this work we expand our understanding of the types of molecules that could store information about extraterrestrial life in alien worlds."
In conventional RNA and DNA, the combination of the four basicbase pairs allows you to store and transmit genetic information. These four building blocks of DNA, or nucleotides, consist of adenine, cytosine, guanine, and thymine, or simply A, C, G, and T. In RNA, T is replaced by uracil (U). Basic bases encode amino acids, the fundamental building blocks of proteins.
Previous studies have allowedsynthetic DNA with a total of four alternative letters in total and a system with two additional base pairs (six in total), but in the latest study, scientists increased this number to eight.
Four new letters, P, B, Z and S, are about the sameaccording to the structures and functionality of ordinary DNA, according to a new study; P and B are purine-like in function, and Z and S are pyrimidine-like. In tests, the genetic system has shown the ability to store and transmit information, essentially imitating the molecular behavior of ordinary four-letter DNA. What is important, the hakimoji also satisfies the requirements of Schrödinger, which define the Darwinian system of molecular evolution (of that Schrödinger, whose cat is neither dead nor alive). Schrödinger described four evolutionary requirements: information storage, transmission, structural integrity, and distinguishable physical form or structure.
"Hachimoji DNA can do everything that DNA doesto sustain life. It predictably pairs, and the rules dictate its stability. Hachimoji DNA can be copied with the creation of hatimoji RNA, it can directly synthesize proteins. Hachimoji RNA can have a selective phenotype (physical structure), and in this experiment, a green fluorescent glow. "
Laurie Haze, Acting DirectorNASA’s Planet Science Department commended the study: “Life is becoming an increasingly important goal of NASA’s planetary science missions, and this new work will help develop effective tools and experiments that will expand our search.”
"This research is important because DNA is alwaysconsidered unique. For example, DNA is the only material with which we can design sequences with predictable stability, ”says Floyd Romesberg, a geneticist from the Scripps Institute, as well as the author of a study with six synthetic pairs. “And as Steve Benner showed, his new four letters also satisfy all aspects of this predictable stability. Although there were hints that other things, besides the four natural letters of DNA, may have such a property, for the first time this work really demonstrates this. ”
Romesberg also says that important useThe eight-letter alphabet consists of controlling molecular associations, that is, the ability to program a configuration of nucleotides. The eight-letter alphabet, in his words, is inherently more specific than the four-letter alphabet.
"However, it will be useless if stabilityan eight-letter alphabet is not predictable or not programmable, ”says Romesberg. “By demonstrating this, Steve discovered new applications that will most likely appear in his laboratory soon.”
The results of the work can lead not only toastrobiological consequences, but also leave a mark in the real world - for example, improve diagnostic equipment, environmental monitoring (such as detection of dangerous viruses), lead to the emergence of alternative information storage, proteins with added amino acids and new innovative drugs.
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