Lovers share colonies of skin microbes, study finds
“You shall not leave alive anything that breathes,” God said in the passage. “But you shall utterly destroy them.”
But a genetic analysis published July 27 has found that the ancient population survived that divine call for their extinction, and their descendants live in modern Lebanon.
“We can see the present-day Lebanese can trace most of their ancestry to the Canaanites or a genetically equivalent population,” said Chris Tyler-smith, a geneticist with the Wellcome Trust Sanger Institute who is an author of the paper. “They derive just over 90 percent of their ancestry from the Canaanites.”
Tyler-smith and an international team of geneticists and archaeologists recovered ancient DNA from bones belonging to five Canaanites retrieved from an excavation site in Sidon, Lebanon, that were 3,650 to 3,750 years old. The team then compared the ancient DNA with the genomes of 99 living people from Lebanon that the group had sequenced. It found that the modern Lebanese people shared about 93 percent of their ancestry with the Bronze Age Sidon samples.
— NICHOLAS ST. FLEUR
Scientists Give a Chrysanthemum the Blues
A blue human is a cold, dead or sad human. We don’t want to be blue. And flowers don’t appear to, either.
Less than 10 percent of 400,000 floral species bear blue flowers.
Scientists and horticulturalists have tried to force blueness upon flowers, but breeding and genetic engineering has not worked out, mainly because there are not many compatible plants with the genetic machinery to manufacture blueness.
Now Japanese scientists have finally created a true blue chrysanthemum — one that passes the strict color standards of the Royal Horticultural Society. Chrysanthemums are usually pink, yellow or red. The scientists hope their methods, published July 26 in Science Advances, can be used to blue-ify other flowers, like roses.
“Plant species blooming blue flowers are relatively rare,” Naonobu Noda, a plant biologist at the National Agriculture and Food Research Organization in Japan who led the research, noted in an email.
It took Noda and his colleagues years to create their blue chrysanthemum. They got close in 2013, engineering a “bluer-colored” one by splicing in a gene from Canterbury bells, which naturally make blue flowers. The resulting blooms were violet. This time, they added a gene from another naturally blue flower called the butterfly pea.
Both of these plants produce pigments for orange, red and purple called delphinidin-based anthocyanins. (They are present in cranberries, grapes and pomegranates, too.) Under a few different conditions, these pigments, which are sensitive to changes in ph, can start a chemical transformation within a flower, rendering it blue.
The additional gene did the trick. It added a sugar molecule to the pigment, shifting the plant’s ph and altering the chrysanthemum’s color. The researchers confirmed the color as blue by testing its wavelengths in the lab. — JOANNA KLEIN
Fungi Physics: How Those Spores Launch Just Right
To spread forth and multiply, fungi — including the familiar button, portobello and shiitake mushrooms — shoot their spores into wafting breezes.
A new paper published July 26 helps explain how fungi aim their spores. Scientists at Duke University constructed larger spores out of plastic spheres and then used an inkjet printer to build water droplets, which are key to the launching mechanism.
The artificial spores and droplets in the experiment were about 10 times the size of ones in nature. That slowed down the motion so it could be captured on video. “With that system, you get what the real spore is doing,” Chuan-hua Chen, a professor of mechanical engineering and materials science at Duke, said.
“This new paper really is an almost miraculous proof of principle,” said Nicholas P. Money, a professor of botany at Miami University in Oxford, Ohio, who was not involved with the experiment.
The energy for propelling the spores turns out to come from the surface tension of water — the forces that cause a drop of water to roll up into a bead on a water-repellent surface.
Mycologists, the scientists who study fungi, now have a tool to study the process more exactly, varying the shape of the spore.
It could conceivably even have practical uses. Imagine a surface that cleans itself, flinging away any dirt particles that land on it. — KENNETH CHANG
Chop Off This Worm’s Head and It Can Still Detect Light
The planarian flatworm is a smooshed noodle of an organism with a triangular head occupied by a rather primitive version of a brain and two black dots for eyes. You can chop off this head, and it will grow back in about a week — eyes, brain and all. And you can hack away at the critter until all that’s left is a tiny speck of worm dust — and the thing will still grow back.
But now this peculiar creature, famous for its regenerative abilities, may have another unforeseen idiosyncrasy: It not only reacts to light after decapitation, but it gradually recoups an ability to see finer aspects of light as its eyes and brain grow back. And despite lacking the machinery to see colors, the worm somehow creates a workaround, essentially converting “this rainbow colored world to a grayscale,” said Akash Gulyani, a multidisciplinary scientist at the National Centre for Biological Sciences in Bangalore, India, who led a new study.
His team’s findings, published last week in Science Advances, could offer new opportunities for studying how animals recover after injuries and reveal additional details about function to the story of how animal eyes evolved.
Although the process is not well-understood in planarians, their ability may be shared by many other organisms: “Simple organisms with simple eyes and a brain can do a lot of complex processing,” said Gulyani. “There are multiple ways in which we sense stimuli and process those stimuli from the outside world, and there are always surprises.”
— JOANNA KLEIN