The key to biology, to the most fundamental of its multiple hierarchical levels, is the specific recognition between molecules: between shapes complementary that fit one another like the two halves of a torn newspaper sheet. A cell membrane receptor knows how to distinguish the right molecule from a bewilderment of other molecules so similar to it that they would defy the expertise of an organic chemist. The antibodies that defend us from infection distinguish one protein from the infectious agent among the millions of existing proteins, and even from the trillions and trillions that could exist. The queen of biological specificity, however, is the DNA sequence (or its cousin the RNA). Read on Matter how scientists have taken advantage of the complementarity between genetic texts, the queen of the specific interaction between molecules, to generate the greatest scientific advance of 2018, according to the magazineScience': The set of genetic techniques that allows us now to study living beings cell by cell, with almost total precision. And knowing the genes that are active in each of them.
It is not just a technical prodigy (it is), but has begun to generate a stream of unsuspected data. For example, the number of cell types in the human body is closer to 30,000 than to the lean 3,000 that we assumed so far. The investigation of only a few has already revealed a new class of cells that mediate between the uterus and the placenta, with fundamental effects on the acceptance or immunological rejection between mother and fetus. It is just an appetizer of what will come, because there are still another 27,000 new cell types to analyze. The "Google Maps of the human body" is what the Barcelona scientist Holger Heyn calls it. You see the whole planet, zoom in and sneak into my room. Or in each of my cells.
The Google Maps of the human body has won even in a difficult year (a good year for science), with very high impact competitors. One of them is the discovery of a first generation human hybrid: a 50,000-year-old Siberian girl who was the daughter of a Neanderthal mother and a Denisovan father, the mysterious species that dominated Asia at the time, and which we only know from its genome and half a dozen bony splinters. Geneticists already knew that modern humans were leaving Africa at the time (the Homo sapiens) had crossed with the Neanderthals in Europe and with the Denisovans in Asia. But none of them, even in their best dreams, had expected to find a first-generation hybrid girl, although in this case it was between Neanderthal and Denisovan. Or those were times of few racial scruples, or more than one Denisovan will be left for prehistory as a rapist.
Other advances of the year are less known, but almost more amazing. One is the essential role, of which we had no idea until recently, of the droplets (droplets) that forms each protein inside our cells, a kind of intracellular ships that distribute them throughout the space in enormous concentrations, in comparison with what proteins could make loose through the cytoplasm. These droplets must be very old and important, since today they are involved in the most fundamental logic of the living cell, its information management mechanisms.
And in 2018 there has been much more. read Matter.
THE SCIENCE OF THE WEEK It is a space in which Javier Sampedro analyzes scientific news. Subscribe to the newsletter of Matter and you will receive it every Saturday in your email, along with a selection of our best news of the week.