Cell biology

The Y chromosome has been notoriously difficult to sequence due to repetitive elements. Junk, right? Now, researchers from the University of Rochester have found a way to sequence a large portion of the Y chromosome in the fruit fly Drosophila melanogaster—the most that the Y chromosome has been assembled in fruit flies. The research, published in the journal GENETICS, provides new insights into the processes that shape the Y chromosome, “and adds to the evidence that, far from a genetic wasteland, Y chromosomes are highly dynamic and have mechanisms to acquire and maintain genes,” says Amanda Larracuente, an assistant professor of biology at Rochester. Using sequence data generated by new technology that reads long strands of individual DNA molecules, Chang Read More ›

Here’s an interesting premise for science finds of 2018: Big, If True. Among them, Bird breathAre white speckles in the chest cavity of a 120-million-year-old bird fossil traces of a respiratory system similar to that of modern birds (SN: 11/10/18, p. 12)? If so, the fossil, found in China, could be the first to preserve lungs of a bird. Some paleontologists aren’t convinced, partly because it’s so rare for delicate lung tissue to survive fossilization. Cassie Martin, “These 2018 findings could be big news — if they turn out to be true” at ScienceNews Note: What makes the Big, If True premise interesting is that researchers were not looking to find this; it happened on them and it raises questions. In Read More ›

This series of videos from McDole et al. shows the development of a mouse embryo, captured using adaptive light-sheet microscopy, and highlights cell division (part A), cell movements (part B) and tissue dynamics (parts C, D) during embryogenesis. Paper. McDole, K., Guignard, L., Amat, F., Berger, A., Malandain, G., Royer, L.A., Turaga, S.C., Branson, K., and Keller, P.K. (2018). In Toto Imaging and Reconstruction of Post-Implantation Mouse Development at the Single-Cell Level. Cell. 175. (paywall) Hat tip: Evolution News and Science Today:

At her blog, Oscillations, Suzan Mazur reports on the lecture series Simons Center for Geometry and Physics has been hosting at Stony Brook University, on Nonequilibrium Physics in Biology: Among the more interesting presenters is Kim Sneppen, a professor of complex systems and biophysics at Neils Bohr Institute in Copenhagen, who addresses the diversity of shapes in the biological world. Sneppen says, “We are basically all doughnuts” and describes how we go from a sphere to a torus in his talk titled: “Theoretical Tool Bridging Cell Polarities with Development of Morphologies.” Suzan Mazur, “Kim Sneppen, Simons Center Talk: “We are basically all doughnuts”” at Oscillations Mazur discusses his approach to embryology and along the way mentions Stuart Pivar, an early Read More ›

Does the interaction between individual animal and microbes form something greater the sum of each, considered separately? Vital functions like digestion and immunity were long assumed to be under the purview of individual organisms, as capabilities developed and were refined through evolution by natural selection — the differential survival and reproduction of individuals. But if our bodies are less an autocracy of identical cells and more a coalition of multitudes, how can we explain their evolution? Some biologists are calling for a radical upgrade of evolutionary theory, arguing that prevailing ideas, developed from the study of bigger, more easily understood organisms, don’t fit nicely into this new world. Others contend that existing theory just needs to be applied more carefully. Read More ›

Researchers Nigel Goldenfeld and Thomas Kuhlman noticed that “half of the human genome is made up of retrotransposons [jumping genes, “junk DNA”], but bacteria hardly have them at all” and wondered what would happen if they just inserted some: “We thought a really simple thing to try was to just take one (retrotransposon) out of my genome and put it into the bacteria just to see what would happen,” Kuhlman said. “And it turned out to be really quite interesting.” Their results, published in the Proceedings of the National Academy of Sciences, give more depth to the history of how advanced life may have emerged billions of years ago—and could also help determine the possibility and nature of life on Read More ›

At her blog, Suzan Mazur interviews neuroscientist Medha Pathak on the recent Mechanome in Action symposium she chaired at UC-Irvine. Pathak “is currently a professor of physiology and biophysics at UCI and heads the Pathak Lab’s investigation there into “how mechanical forces modulate neural stem cell fate in development and repair.” Suzan Mazur: If you google “mechanome,” you don’t see that many references to it. Medha Pathak: The term is catching on. The first Mechbio conference, organized by colleagues Padmini Rangamani, Juan Carlos del Alamo and Debanjan Mukherjee in 2016 at UC-San Diego, was called “Putting Together the Cell Mechanome: Finding the pieces, building the puzzle.” When organizing the 2018 conference, the second one in the series, we—Jun Allard, Albert Read More ›

From ScienceDaily: So audacious was Marcus Bray’s experiment that even he feared it would fail. In the system inside cells that translates genetic code into life, he replaced about 1,000 essential linchpins with primitive substitutes to see if the translational system would survive and function. It seemed impossible, yet it worked swimmingly, and Bray had compelling evidence that the great builder of proteins was active in the harsh conditions in which it evolved 4 billion years ago. The experiment’s success reaffirmed the translational system’s place at the earliest foundations of life on Earth. Every living thing exists because the translational system receives messages from DNA delivered to it by RNA and translates the messages into proteins. The system centers on Read More ›