In 2017, heredity specialists provided the world with incredible new genetic editing tools and discovered the vulnerabilities of bacteria and viruses. In addition, they made a number of fundamental discoveries that brought us closer to understanding the phenomenon of life. We have selected the top 10 discoveries and advances in genetics for 2017.
1. For the first time edited the genome of a living person
The operation was performed in California by employees of Sangamo Therapeutics. All other experiments, with the exception of one in China, about which little is known, were carried out exclusively on samples of embryonic tissue.
For a 44-year-old patient, genome editing was the last chance. Brian Made suffers from Hunter Syndrome, which is the inability of the liver to produce an important enzyme for the breakdown of mucopolysaccharides. The enzyme has to be injected artificially, which is very expensive; moreover, to combat the consequences of the disease, Made had to go through 26 operations. To help Brian, he was injected intravenously with billions of copies of corrective genes, as well as genetic tools that must cut DNA in specific places. The genome of liver cells must change for the rest of your life. If the treatment is successful, the researchers will continue to experiment with other inherited diseases.
2. Created a stable semi-synthetic organism
All life on Earth is based on four letter-nucleic bases: adenine, thymine, cytosine and guanine (A, T, C, G). Using this alphabet, you can create any living organism, from bacteria to whales. Scientists have been trying to “crack” this code for a long time, and this year they finally succeeded. The breakthrough was made by geneticists from the Scripps Research Institute. They supplemented the genetic alphabet with two new letters – X and Y, which they inserted into the DNA of E. coli.
They learned to introduce artificial letters into DNA several years ago, the real breakthrough in 2017 was the stability of an artificial organism. Previously, the X and Y bases were lost during divisions, and the descendants of the modified bacteria quickly returned to the “wild” state. Thanks to the improvement of technologies and changes made to the base Y, it was possible to achieve the preservation of artificial “letters” in the genome of bacteria for 60 generations. The application of the new technology in practice is still a matter of the future – it may be possible to apply it to impart new properties to microorganisms. In the meantime, for researchers more important is the fact that they have managed to modify one of the fundamental mechanisms of life.
3. Discovered “space gene”
The world is undergoing a “space renaissance”: companies led by SpaceX are rushing into space one after another, and governments are planning to build colonies on Mars and the Moon. However, we shouldn’t forget that for millions of years our species and its ancestors have evolved to live on the surface of the Earth. It is important to know in advance how a long stay in space and on other planets will affect the human body in order to take the necessary protective measures. Fortunately, the researchers had such an opportunity – astronaut Scott Kelly, who spent about a year on the ISS, and his twin brother Mark, who remained on Earth, agreed to a complete examination of their organisms.
In addition to the expected physiological changes caused by weightlessness, scientists were surprised to find differences in the brothers’ genomes. Scott showed a temporary lengthening of telomeres – the ends of chromosomes, as well as changes in the expression of more than 200,000 RNA molecules. The process of turning thousands of genes on and off has been transformed by being in space. Scientists have called the totality of these changes the “cosmic genome.” It is not yet known how he influenced Scott’s health – experiments with the Kelly twins are ongoing.
4. Proven the effectiveness of genetic therapy
In 2017, CRISPR and other genetic editing technologies were increasingly used to combat various diseases. Unlike the case of Brian Made, most of these techniques do not require large-scale modifications of the genome, and the cells are edited not in the patient’s body, but in the laboratory. Such methods are called genetic therapy. In the past year, researchers have repeatedly proven its effectiveness against various diseases.
The most striking example is the fight against a dangerous disease, which itself is of a genetic nature. We are talking about cancer – more precisely, so far only about some of its varieties. Researchers have demonstrated that by taking immune cells from patients with lymphoma, using gene editing to tune them to fight the tumor and injecting them back into the patient, a high percentage of remission can be achieved. The method, patented under the name Kymriah ™, was approved by the FDA in August 2017.
5. Antibiotic resistance explained at the molecular level
In 2017, concerned scientists announced the end of the antibiotic era. A drug that has saved millions of lives for nearly a century is quickly becoming ineffective due to the emergence of antibiotic-resistant bacteria. This is due to the rapid multiplication of microorganisms and their ability to exchange genes. One bacterium that has learned to resist the effects of drugs will pass on this skill not only to its offspring, but also to any members of its species that are nearby.
However, while some are writing manifestos calling on governments and the public, others are looking for vulnerabilities in superbugs. By understanding the molecular basis of drug resistance, we can effectively counter superbugs. Danish scientists were the first to prove that resistance genes and antibiotic genes are related to each other. Microorganisms of the genus Actinobacteria produce both antibiotics and substances that can neutralize them. Disease-causing bacteria are able to “steal” genes that are responsible for resistance from actinobacteria and spread them throughout the population. Although no one can stop horizontal gene transfer, the discovered mechanism will allow finding new means of combating superbugs.
6. Genes for longevity have been identified
Unlike various diseases that can be learned to heal, aging is a truly existential problem. Researchers are determined to “undo” it, but we do not yet know for sure neither the mechanisms of aging, nor the consequences that its disappearance will produce in society. However, experts are optimistic. In 2017, there were a number of studies in the genetics of aging that could be the key to solving the problem.
One of the directions was the search for mutations associated with longevity. One of them was found in the Amish community. The mutation was responsible for decreased levels of plasminogen activator inhibitor (PAI-1). Its speakers lived on average 14 years longer than other Amish people (85 versus 71). They were also less likely to suffer from age-related diseases, and their telomeres were longer. Other studies have shown that mutation of the growth hormone receptor increases life expectancy in men, and that intelligence is genetically linked to slow aging. Also in the past year, Chinese scientists discovered a gene for longevity in worms. On the basis of all these works, one can try to create a real cure for old age. Perhaps one of the methods will be genetic correction of mitochondria – intracellular batteries that lose flexibility with age.