“Campesinos” are driving the evolution of maize in North America.
An international team of astronomers has detected a new luminous quasar at a redshift of 7.02. The newly found quasi-stellar object (QSO), designated DELS J003836.10–152723.6, is the most luminous quasar known at a redshift of over 7.0. The discovery is reported in a paper published October 29 on the arXiv pre-print repository.
Powered by the most massive black holes, bright quasars at high redshift are important for astronomers as they are perceived as the brightest beacons highlighting the chemical evolution of the universe most effectively. They are the most luminous and most distant, compact objects in the observable universe and their spectrum can be used, for instance, to estimate the mass of supermassive black holes (SMBHs).
However, high-redshift QSOs are extremely rare and difficult to find. So far, only two quasars with redshifts over 7.0 have been identified. This limits our understanding of SMBH growth mechanism and reionization history.
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The history of human evolution has been rewritten after scientists discovered that Europe was the birthplace of mankind, not Africa.
Currently, most experts believe that our human lineage split from apes around seven million years ago in central Africa, where hominids remained for the next five million years before venturing further afield.
But two fossils of an ape-like creature which had human-like teeth have been found in Bulgaria and Greece, dating to 7.2 million years ago.
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Almost half of our DNA sequences are made up of jumping genes—also known as transposons. They jump around the genome in developing sperm and egg cells and are important to evolution. But their mobilization can also cause new mutations that lead to diseases, such as hemophilia and cancer. Remarkably little is known about when and where their movements occur in developing reproductive cells, the key process that ensures their propagation in future generations, but can lead to genetic disorders for the hosts.
To address this problem, a team of Carnegie researchers developed new techniques to track the mobilization of jumping genes. They found that during a particular period of egg development, a group of jumping-genes called retrotransposons hijacks special cells called nurse cells that nurture the developing eggs. These jumping genes use nurse cells to produce invasive material (copies of themselves called virus-like particles) that move into a nearby egg and then mobilize into the egg’s DNA. The research is published in the July 26 on-line issue of Cell.
Animals have unwittingly developed a powerful system to suppress jumping gene activity that uses small, non-coding RNAs called piRNAs, which recognize jumping genes and suppress their activity. Occasionally, jumping genes still manage to move, suggesting that they employ some special tactics to escape piRNA control. However, tracking the mobilization of jumping genes to understand their tactics has been a daunting task.
Perhaps the most important supernova of the modern era is SN 1987A, the closest supernova to Earth since the invention of the telescope. Scientists have been observing the explosion’s remnants since the 1987 event.
Scientists led by University of Toronto graduate student Yvette Cendes have presented a new report showing the 25 years of radio wave observations of the stellar corpse’s evolution from 1992 to 2017. You can watch those observations in the timelapse below.
Maybe they’re not alien doppelgangers — mirror images of us.
But extraterrestrial life—should it exist—might look “eerily similar to the life we see on Earth,” says Charles Cockell, professor of astrobiology at the University of Edinburgh in Scotland.
Indeed, Cockell’s new book (The Equations of Life: How Physics Shapes Evolution, Basic Books, 352 pages) suggests a “universal biology.” Alien adaptations, significantly resembling terrestrial life—from humanoids to hummingbirds—may have emerged on billions of worlds.
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Humans are exterminating animal and plant species so quickly that nature’s built-in defence mechanism, evolution, cannot keep up. An Aarhus-led research team calculated that if current conservation efforts are not improved, so many mammal species will become extinct during the next five decades that nature will need 3 to 5 million years to recover.
There have been five upheavals over the past 450 million years when the environment has changed so dramatically that the majority of Earth’s plant and animal species became extinct. After each mass extinction, evolution has slowly filled in the gaps with new species.
The sixth mass extinction is happening now, but this time, the extinctions are not being caused by natural disasters; they are the work of humans. A team of researchers from Aarhus University and the University of Gothenburg has calculated that the extinctions are moving too rapidly for evolution to keep up.
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“Once such superhumans appear, there are going to be significant political problems with the unimproved humans, who won’t be able to compete,” suggests the late physicist and author Stephen Hawking in The Sunday Times. “Presumably, they will die out, or become unimportant. Instead, there will be a race of self-designing beings who are improving themselves at an ever-increasing rate. If the human race manages to redesign itself, it will probably spread out and colonize other planets and stars.”
Hawking has caused an uproar by suggesting a new race of superhumans could develop from wealthy people choosing to edit their DNA. “There is no time to wait for Darwinian evolution to make us more intelligent and better natured. But we are now entering a new phase of what might be called self-designed evolution, in which we will be able to change and improve our DNA. We have now mapped DNA, which means we have read “the book of life”, so we can start writing in corrections.”
Hawking, who died in March, presented the possibility that genetic engineering could create a new species of superhuman that could destroy the rest of humanity. The essays, published in the Sunday Times, were written in preparation for a book that will be published on Tuesday.
Only time will tell what new forms life will take.
Joyce seeks to understand life by trying to generate simple living systems in the lab. In doing so, he and other synthetic biologists bring new kinds of life into being. Every attempt to synthesize novel life forms points to the fact that there are still more, perhaps infinite, possibilities for how life could be. Synthetic biologists could change the way life evolves, or its capacity to evolve at all. Their work raises new questions about a definition of life based on evolution. How to categorize life that is redesigned, the product of a break in the chain of evolutionary descent?
An origin story for synthetic biology goes like this: in 1997, Drew Endy, one of the founders of synthetic biology and now a professor of bioengineering at Stanford University in California, was trying to create a computational model of the simplest life form he could find: the bacteriophage T7, a virus that infects E coli bacteria. A crystalline head atop spindly legs, it looks like a landing capsule touching down on the Moon as it grabs onto its bacterial host. The bacteriophage is so simple that by some definitions it is not even alive. (Like all viruses, it depends on the molecular machinery of its host cell to replicate.) Bacteriophage T7 has only 56 genes, and Endy thought it might be possible to create a model that accounted for every part of the phage and how those parts worked together: a perfect representation that would predict how the phage would change if any one of its genes were moved or deleted.
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