Lifeboat Foundation

Even genes essential for life can be caught in an evolutionary arms race that forces them to change or be replaced.

Circa 2013

The Book of Genesis puts Adam and Eve together in the Garden of Eden, but geneticists’ version of the duo — the ancestors to whom the Y chromosomes and mitochondrial DNA of today’s humans can be traced — were thought to have lived tens of thousands of years apart. Now, two major studies of modern humans’ Y chromosomes suggest that ‘Y-chromosome Adam’ and ‘mitochondrial Eve’ may have lived around the same time after all^{1, 2}.

When the overall population size does not change (as is likely to have happened for long periods of human history), men have, on average, just one son. In this case, evolutionary theory predicts that for any given man there is a high probability that his paternal line will eventually come to an end. All of his male descendants will then have inherited Y chromosomes from other men. In fact, it is highly probable that at some point in the past, all men except one possessed Y chromosomes that by now are extinct. All men living now, then, would have a Y chromosome descended from that one man — identified as Y-chromosome Adam. (The biblical reference is a bit of a misnomer because this Adam was by no means the only man alive at his time.)

Continue reading “Genetic Adam and Eve did not live too far apart in time” »

Circa 2013

A group of scientists from Kyoto has managed to successfully analyze and “record” the basic elements of what people see when they dream. The idea of recording dreams has been a mainstay in science fiction, but also a frequent goal for researchers. As Smithsonian Magazine writes, this group designed its study based on the premise that brains react to “seeing” objects with repeatable patterns that can be measured with MRI. If a machine can recognize the patterns well enough, it can reverse-engineer them, giving us a window into what’s going on inside people’s heads while they dream.

Three participants were selected for a study and asked to sleep for several three-hour blocks in an MRI scanner. Once they fell asleep, scientists woke them up and asked them to describe what they’d seen in the dream, grouping them into loose categories and sub-categories like “car,” “male,” “female,” or “dwelling.” The group then picked representations of those categories from an online image search and showed them to the participants, once again measuring their brain activity to figure out what patterns might be unique to that concept. Finally, the participants were asked to sleep again, but this time, a machine wouldn’t simply record how their brain responded to dreaming — it would attempt to match it to one of the categories with a series of images, as seen in the video below.

Continue reading “Scientists turn dreams into eerie short films with an MRI scan” »

A new study challenges a long-held belief that essential genes change little over time.

First introduced into wide use in the middle of the 20th century, nuclear magnetic resonance (NMR) has since become an indispensable technique for examining materials down to their atoms, revealing molecular structure and other details without interfering with the material itself.

“It’s a broadly used technique in chemical analysis, materials characterization, MRI—situations in which you do a non-invasive analysis, but with atomic and molecular details,” said UC Santa Barbara chemistry professor Songi Han. By placing a sample in a strong magnetic field and then probing it with radio waves scientists can determine from the response from the oscillating nuclei in the material’s atoms the molecular structure of the material.

“However, the problem with NMR has been that because it’s such a low-energy technique, it’s not very sensitive,” Han said. “It’s very detailed, but you don’t get much signal.” As a result, large amounts of sample material may be needed relative to other techniques, and the signals’ general weakness makes NMR less than ideal for studying complex chemical processes.

Current state-of-the-art techniques have clear limitations when it comes to imaging the smallest nanoparticles, making it difficult for researchers to study viruses and other structures at the molecular level.

Scientists from the University of Houston and the University of Texas M.D. Anderson Cancer Center have reported in Nature Communications a new optical imaging technology for nanoscale objects, relying upon unscattered light to detect nanoparticles as small as 25 nanometers in diameter. The technology, known as PANORAMA, uses a glass slide covered with gold nanodiscs, allowing scientists to monitor changes in the transmission of light and determine the target’s characteristics.

PANORAMA takes its name from Plasmonic Nano-aperture Label-free Imaging (PlAsmonic NanO-apeRture lAbel-free iMAging), signifying the key characteristics of the technology. PANORAMA can be used to detect, count and determine the size of individual dielectric nanoparticles.

2021 may not turn out well.

He’s hoping the world’s billionaires will donate their pandemic profits.

Maithra Raghu, a research scientist at Google Brain, is betting that neural networks can become a powerful tool in medicine.

NAD+ (nicotinamide adenine dinucleotide), a key metabolite central to an efficient and healthy metabolism, declines with age. This previously unexplained phenomena is associated with numerous age-related diseases and has spawned the development of many nutritional supplements aimed at restoring NAD+ to more youthful levels. Publishing in Nature Metabolism, researchers at the Buck Institute have identified chronic inflammation as a driver of NAD+ decline. They show that an increasing burden of senescent cells, which is also implicated in the aging process, causes the degradation of NAD via the activation of CD38 (cyclic ADP ribose hydrolase) a protein that is found on the cell membranes both inside and on the surface of many immune cells.

“We are very excited to link two phenomena which have been separately associated with aging and age-related disease,” said Eric Verdin, MD, Buck Institute President and CEO and senior author of the paper. “The fact that NAD+ decline and chronic inflammation are intertwined provides a more holistic, systemic approach to aging and the discovery of CD38 macrophages as the mediator of the link between the two gives us a new target for therapeutic interventions.”