Science news digest – 25 February 2013
In the science news this week, scientists are divided on ‘junk DNA’ dilemma, people in vegetative state may feel pain, ancient continent found under the Indian Ocean, and finally… Vulcan is the most popular choice for name of Plutonian moon.
Scientists attacked over claims that ‘junk DNA’ isn’t junk after all
One of the major science stories of 2012 came from the announcement by a group of scientists working on the Encode project who claimed they had found that ‘junk DNA’ was in fact not junk at all, but was vital to life.
However, last week, another team published a vitriolic attack on the first group claiming they knew nothing about evolutionary biology, reported the Guardian.
The row has divided scientists on a fairly fundamental question – whether our DNA is made up of mostly useless junk that fills in the gaps between the most important cells, or whether this DNA also has a purpose in our cells.
“Everything that Encode claims is wrong. Their statistics are horrible, for a start," said the lead author of the paper, Professor Dan Graur, of Houston University, Texas. "This is not the work of scientists. This is the work of a group of badly trained technicians."
However, the Encode researchers were not going to take the comments lying down: "The nature of the attacks against us is quite unfair and uncalled-for," said Dr Ewan Birney, of the European Bioinformatics Institute, near Cambridge, a principal investigator in the five-year project. "Our work has very important implications for understanding disease susceptibility."
When the human genome was first sequenced nearly 13 years ago, only 26,000 genes were shown to be directing the manufacture of proteins and growth control, leaving 98 per cent of human DNA being written off.
However, the research from the Encode project suggested otherwise, claiming that they had identified 10,000 new genes and suggesting that as much as 18 per cent of our DNA is responsible for regulating other genes. They also said that about 80 per cent of our DNA had a biochemical function.
Not only that, but the group also identified defects in DNA which could lead to illnesses such as Crohn’s disease, diabetes, and bipolar disorder.
However, Graur and others, claim that these findings are “absurd” and that the Encode project used “analytical methods that yield biased errors and inflate estimates of functionality".
“Just because a piece of DNA has biological activity does not mean it has an important function in a cell," said Graur. "The Encode people don't seem to have grasped that point. They completely exaggerated the amount of human DNA that has a role to play inside our cells. Most of the human genome is devoid of function and these people are wrong to say otherwise."
People in a vegetative state may feel pain
A study at the Schön clinic in Bad Aibling, Germany have found that people with unresponsive wakefulness syndrome (UWS) – also known as being in a vegetative state – may be able to experience pain. The team have identified brain activity in areas that are typically associated with the emotional aspects of pain, reported New Scientist.
There are two distinct neural networks in the brain that work together to create the sensation of pain. The more basic of the two – the sensory-discriminative network – simply identifies the presence of pain source. The other network – known as the affective network – attaches emotions and subjective feelings to the experience. Without this second phase, a person’s brain is able to detect pain but won’t interpret it as unpleasant.
Previous studies of people with UWS have shown that there has been activity in the sensory-discriminative network when exposed to a painful stimulus, but the findings suggested that there was no emotional attachment to the pain.
This latest study has found, however, that there are cases where brain activity is seen in the affective network as well.
The team gave moderately painful electric shocks to 30 people with UWS, whilst scanning their brains in an fMRI machine. Sixteen of the patients showed some brain activity – seven with activity in the sensory network alone, but nine with activity in both networks.
These results may bring into question whether some patients should have a changed diagnosis from UWS to minimally conscious, which is characterised by having some level of awareness.
Fragments of ancient continent found in Indian Ocean
A study has found evidence of an ancient continent buried beneath the floor of the Indian Ocean, reported the BBC news website.
The strip of land, which has been dubbed Mauritia, would have broken up and vanished beneath the ocean as the tectonic plates moved into their current positions.
Until about 750 million years ago, the Earth’s landmass was clustered together in a single supercontinent called Rodinia.
At this time, India and Madagascar were situated next to each other. However, researchers have now found evidence of a sliver of continent that was tucked between the two before they moved apart.
The researchers have studied the grains of sand on the beaches of Mauritius, and have found that although the grains date back to a volcanic eruption that happened about nine million years ago, the minerals that make up the grains were much, much older.
Professor Trond Torsvik, from the University of Oslo, Norway, said: "We found zircons that we extracted from the beach sands, and these are something you typically find in a continental crust. They are very old in age."
"At the moment the Seychelles is a piece of granite, or continental crust, which is sitting practically in the middle of the Indian Ocean," explained Prof Torsvik.
"But once upon a time, it was sitting north of Madagascar. And what we are saying is that maybe this was much bigger, and there are many of these continental fragments that are spread around in the ocean."
‘Vulcan’ leads vote for name of Pluto moon
A vote on the names for two newly discovered Plutonian moons is currently being led by the name ‘Vulcan’, reported the BBC.
Vulcan has most famously been associated with the home planet of Spock, a character from Star Trek. The vote has had a lot of support from actor William Shatner, who played Captain James T. Kirk in the original series and a number of films.
The poll is being run by the Seti Institute in California and Dr Mark Showalter, who led the team that discovered the two moons, currently known as P4 and P5, in 2011.
The team have said that they would take the results of the vote into consideration when they propose their name choices to the International Astronomical Union (IAU).
However, Star Trek fans shouldn’t get too excited – the IAU has the final say on the naming of the moons, and there is no guarantee they will accept the names proposed by the team, nor the ones most popular in the vote.