Neanderthal genes found in African populations

Usually the main theories about Neanderthal migrations have told us that this group of hominids settled mostly in Europe and then moved to Asia and that the genes they introduced in some populations of Homo sapiens would concern only European and not African populations. However, a new study, published in the journal Cell and conducted by a team of researchers at Princeton, shows that this is not the case: Neanderthal genes may have also “taken root” in African populations, albeit indirectly.

Through a new method of DNA analysis from ancient bones, Princeton researchers have found Neanderthal origins in African and non-African populations. This is the first time that traces of Neanderthals have been found in the Africans, as pointed out by Lu Chen, one of the authors of the study and researcher at the Lewis-Sigler Institute for Integrative Genomics (LSI).

The researchers’ analyses showed that the migration of European populations to Africa introduced Neanderthal genes into African populations.

And it would not have been a direct cross between Neanderthals themselves and African populations: the genes would have come from Homo sapiens populations that already had part of the Neanderthal genome within their DNA. So the theory that Neanderthals would never have frequented Africa still holds.

The migrations of humans who had Neanderthal genes to Africa would have occurred at least 100,000 years ago, before the migrations of African populations to Europe which then led to the modern colonization of Europe and Asia.

“This shows that the remnants of the Neanderthal genome survive in every modern human population studied to date,” stresses Chen.


See also:

https://www.cell.com/cell/fulltext/S0092-8674(20)30059-3

Device invented that makes jellyfish move faster

A prosthesis to make jellyfish swim faster: that’s the idea that came from a group of engineers at Caltech and Stanford University. The researchers have made a small prosthesis that allows the jellyfish themselves to be more efficient in swimming and all this without creating any kind of stress to the animals, according to the scientists themselves.

This 2 cm large prosthesis makes use of small electrical impulses to regulate the pulsating movement that these animals naturally perform to push themselves forward. They swing their tentacles and this gives them the push to move forward or even to jump on prey. With this microelectronic controller, the animals are able to pulsate three times faster than normal and this causes an acceleration of movement and allows them a speed of motion of approximately 4-6 cm/s.

They also consume half the energy they would consume if they went at this speed without the controller. As mentioned above, the animals do not suffer any side effects, which has been carefully evaluated by the researchers themselves over many hours of observation. They couldn’t assess their pain because they don’t have a brain or receptors but they paid attention to a phenomenon that happens in the jellyfish body when they are stressed: they secrete mucus and this was not observed by researchers.

However, such an effort is not an end in itself or in any case only aimed at making some jellyfish more efficient in its movement: these animals, in fact, could be exploited to explore and perform ocean surveys.

“If we can find a way to direct these jellyfish and also equip them with sensors to track things like ocean temperature, salinity, oxygen levels and so on, we could create a truly global ocean network in which each of the robot jellyfish costs a few dollars and feeds on energy from prey already present in the ocean,” reports John Dabiri of Caltech, one of the authors of the study published in Science Advances.


See also:

https://advances.sciencemag.org/content/6/5/eaaz3194

The Pacific Northwest Temperature ranged widely between 800,000 and 750,000 years ago

Surface water temperature in the Northwest Pacific Ocean fluctuated widely between 800,000 and 750,000 years ago according to a new study conducted by a team of researchers from the National Institute of Polar Research (NIPR) and Ibaraki University. The researchers analyzed the oxygen isotopes of some fossils of foraminiferous, amoeboid marine microorganisms found on the island of Honshu, Japan.

According to the researchers, these changes were due to the discharge in this marine area of massive amounts of water derived from ice melting in the North Atlantic. This study could also be useful to understand climate change in the same area in the future.

According to the researchers, in fact, in order to assess the anthropogenic effects on ongoing climate change, it is necessary to make comparisons with the climates and environmental conditions that have occurred in the past, changes that naturally had no anthropogenic causes.

The study, published in the Earth and Planetary Science Letters, describes the methods researchers used to collect and then analyze fossils of four species of foraminifera taken from the MIS layer19. This sediment layer refers to a hot interglacial period of 790,000 to 760,000 years ago.

Based on previous studies that had shown that low oxygen isotope values of foraminiferous fossils correspond to higher water temperatures, the researchers came to the conclusion that there must be, in addition to the glacial-interglacial cycle that repeats on time scales of tens of thousands of years, other cycles related to water temperature.

Specifically, this temperature would oscillate in an extreme way, of about 7°, every few thousand years. In addition, analyses seem to show that these changes have occurred due to the outflow of water from icebergs in the North Atlantic.

“Surprisingly, the changes in the North Atlantic have caused dramatic fluctuations in water temperature in the remote Pacific Northwest,” says Yuki Haneda, NIPR scientist and one of the authors of the study. “We believe that the fossils collected from the outcrop are a tracer that integrates the data reported from deep water sediments. The composite section of Chiba is the global boundary stratification section and point (GSSP) of the lower-middle Pleistocene boundary and offers a remarkable understanding of global environmental changes during that period. We want to improve our understanding of climate change during MIS19 to predict future climate change more accurately.”