In the science news this week, a widespread extinction of bees that was caused by meteor impact, most distant galaxy baffles astronomers, and finally… researchers find some of the genes linked to facial features.
Mass extinction of bees caused by meteor strike
The meteor impact 66 million years ago that wiped out the dinosaurs, may have also been the cause of a widespread extinction of bees, reported the BBC .
Previous studies had suggested that a number of flowering plants were affected by the Cretaceous-Paleogene (K-Pg) extinction event 66 million years ago, suggesting that the bees that depended on these plants must also have felt the effect.
However, unlike with the dinosaurs, there are relatively poor fossil records for bees from this time.
This new research, published in Plos One, used fossils and DNA analysis to show that one bee group in particular suffered a serious decline at the time of the meteor strike.
The team chose to study the bees within the subfamily known as Xylocopinae – a subfamily that includes carpenter bees – because the evolutionary history can be traced back to the Cretaceous Period for this particular group.
They also studied flower fossils, which had evolved traits that allowed them to be pollinated by bee relatives of the Xylocopinae.
"The data told us something major was happening in four different groups of bees at the same time," said Sandra Rehan, from the University of New Hampshire, who was lead author of the study.
"And it happened to be the same time as the dinosaurs went extinct.
"Understanding extinctions and the effects of declines in the past can help us understand the pollinator decline and the global crisis in pollinators today," Rehan explained.
Most distant galaxy ever observed was a prolific star factory
The most distant and oldest galaxy ever seen has been spotted by astronomers using the Keck telescope, which sits on the summit of Mauna Kea, a dormant volcano in Hawaii.
The group of stars is 30 billion light years from Earth and has only recently been observed after a new infrared instrument was fitted to the telescope last year, reported the Guardian .
Analysis of the light coming from the galaxy showed that it formed just 700 million years after the big bang, or 13.1 billion years ago.
"This is really a quest to understand our origins," said Steve Finkelstein, an astronomer at the University of Texas at Austin. "By trying to push further and further back in time, we are really studying the origins of our own Milky Way galaxy."
Early measurements suggest that this galaxy is 40 to 50 times lighter than the Milky Way with a mass of roughly 1 billion suns. But what surprised astronomers was the incredible rate that the galaxy is creating stars – around 150 times faster than our own galaxy.
"We didn't think you could make galaxies with such intense star formation rates in the early universe. Star formation tends to be proportional to the mass of a galaxy, and the masses of galaxies in the early universe tend to be small," said Finkelstein.
It could be that the galaxy has more gas than expected, or that it is drawing in gas much faster from the space between galaxies. Finkelstein hopes that further analysis will be able to answer this question.
Scientists find clues on how genes shape the face
Researchers have identified thousands of small regions of DNA that help shape the facial features as well as finding tweaks that can subtly alter them. The study, carried out on mice, could help researchers learn more about how facial birth defects develop and potentially how to stop them, reported the BBC .
Professor Axel Visel, from the Joint Genome Institute at the Lawrence Berkeley National Laboratory in California, told BBC News: "We're trying to find out how these instructions for building the human face are embedded in human DNA.
"Somewhere in there there must be that blueprint that defines what our face looks like."
The team have found over 4,000 enhancers in the mouse genome that affect the shape and structure of the face. These enhancers are short stretches of DNA that can act like switches, turning certain genes on or off.
For 200 of these enhancers, the researchers have also identified how and where they influence the face of a developing mouse.
Prof Visel said: "In the mouse embryos we can see where exactly, as the face develops, this switch turns on the gene that it controls.
"These mice looked pretty normal, but it is really hard for humans to see differences in the face of mice," explained Prof Visel.
"The way we can get around this is to use CT scans to study the shapes of the skulls of these mice. We take them and scan their heads. Then we can measure the shape of the skull of these mice and we can do this in a very precise way."