In the genetic code of a single cell made more than 13 thousand changes.

Using a modified version of the technology of gene editing CRISPR, a group of researchers from Harvard University successfully made 13,200 changes to the genetic code of a single living cell. This was a new record in this area, far surpassing the previous similar record in terms of the number of changes, but the most incredible was that the cell managed to survive after all modifications. Such technology can be used in the future to “clean” human DNA from useless or dangerous genetic information. In addition, new technology can be used to create completely new types of synthetic life.

The goal of this work is to create a “pure genome” that will make it invulnerable to viruses of any type of tissue of artificially grown human organs. This process, called genome transcoding, involves a minimum of 9,811 precise changes. The first type of cells that went through the process of transcoding the genome in the laboratory was universal stem cells.

Researchers have focused on removing and disabling the problematic type of a piece of genetic code, a transposon, known as LINE-1. Such transposons are known as “jumping genes” because they are able to “jump” from one location to another. Such tanspozons are quite common in the mammalian genome, including in the human genome, a little less than half of the entire genome falls on transposons, the functional utility of which is still the cause of disputes between scientists.

The LINE-1 transposon accounts for about 17 percent of the entire human genome, with many problems associated with it, including gene degradation, neurological diseases, and aging. In the transposon code LINE-1, many mutations have accumulated over time, and this code does not contain anything useful for humans.

To clean the genome, scientists first tried to use conventional CRISPR technology to search for and destroy LINE-1 transposon sequences. However, this approach worked well when there were several target sites in the genome, but after the CRISPR technology worked on hundreds and thousands of sites, the genome turned into a continuous useless “mess”, which led to cell death that went through the procedure.

After the failure of the traditional CRISPR technology, the scientists decided to use its modified version. Instead of “cutting” the DNA, the new variant simply changes the code, replacing, for example, G with A. Such a replacement does not cause catastrophic effects and allows editing of thousands of sections in one strand of DNA, keeping the cell completely in a viable state.

The 13,200 changes produced are nearly half of the 26,000 active transposons LINE-1 in the human cell genome. “We hope that in the near future we will be able to eliminate all 100 percent of the active elements of LINE transposons,” the researchers write, “However, before that, we will need to conduct a series of comprehensive studies to assess the effects of such a massive intervention in the genome. cause side mutations that will become a big problem. For this we will need new biological controls, new experimental methods and new software algorithms from the so-called domain bioinformatics. ”

Picture Credit: geralt

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The 52-million-year-old fossil of Eofringillirostrum boudreauxi, the earliest known perching bird with a beak for eating seeds. Credit: (c) Lance Grande,  Field Museum.

In the United States, well-preserved fossils of an ancient bird that could peck hard seeds were found, according to Current Biology. This is indicated by its beak, which resembles a beak. Eofringillirostrum boudreauxi, as the bird was called, lived about 52 million years ago.

The shape of the beak played an important role in the emergence of different species of birds, so when studying the evolution of birds, researchers first of all pay attention to this feature. Perhaps the most closely associated with the study of the shape of the beak is the passer-shaped – the most numerous order of birds, which includes about 5.4 thousand species. The variety of beak shape allows passerine to catch insects, eat carrion, peck hard seeds and drink nectar from flowers. However, the evolution of the beak in passerines has not been studied as yet, since researchers rarely find their fossils.

In a new study, paleontologists Daniel Ksepka and Lance Grande from the Field Natural History Museum and Gerald Mayr from the Zenkenberg Research Institute describe two ancient passerine fossils. Scientists attributed them to one genus and two new species. The fossils of one of the birds were found in Wyoming in the Green River sediments. Eofringillirostrum boudreauxi, as scientists called it, lived in the Middle Eocene, about 52 million years ago. The remains of the second bird, Eofringillirostrum parvulum, were found in southwest Germany. She was much younger than E.boudreauxi and lived about 47 million years ago. In size, both birds were similar to the Canadian nuthatch – about 11 centimeters in length and weighed about ten grams. E.boudreauxi was slightly larger than E.parvulum.

The birds had a short upper part of the beak of conical shape, which narrowed to a thin tip. In appearance, it resembled the beak of a modern American chizh, which feeds on seeds, including sunflower seeds. “These beaks are well adapted to feed on small, hard seeds,” says Daniel Ksepka. “The most ancient birds, apparently, fed on insects and fish. Some may have eaten little lizards. Prior to this discovery, we knew little about the ecology of early passer-shaped birds. E.boudreauxi gives us important information about her. ”
Previously, ornithologists had attracted volunteers to study the evolution of bird beaks. Scientists conducted a 3D-scan of the beaks of more than two thousand species of birds and laid out models on the site, and volunteers marked them out.

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