DNA differences which appear to affect the risk of giving birth early have been found by US scientists.
The US National Institutes of Health study found the variants in both babies and mothers, a US conference was told.
It is thought they may play a role in controlling immune responses which could theoretically trigger labour if they become too powerful.
Premature birth - which accounts for 7% of UK births - is one of the biggest threats to a baby's future health.
The causes of premature birth are poorly understood, although infections and other medical complications are blamed in some cases.
The study looked at 700 DNA variants in 190 genes in women who delivered early, and those who carried their baby to term.
The cord blood of the babies was also tested for these variations.
They narrowed the search down to a handful of gene variations found more often in the women who gave birth prematurely, and their babies.
In particular, babies who carried the gene for the "Interleukin 6 receptor" were more likely to be born early.
This was a good candidate gene because Interleukin 6 is produced by cells in response to infection and is involved in inflammation.
High levels of Interleukin 6 in the amniotic fluid and foetal blood have been linked to the onset of premature labour.
Baby threat
Dr Roberto Romero, who led the study, said: "Our hypothesis is that the mother and/or the foetus signal the onset of preterm labour when the environment inside the uterus is unfavourable and threatens the survival of the maternal-foetal pair.
"When there is an infection in the uterus, the onset of premature labour appears to have survival value - it would allow the mother to rid herself of infected tissue and preserve her ability to have future pregnancies."
The chief executive of charity Bliss, Andy Cole, welcomed the study results.
"In England alone, 54,000 babies are born prematurely each year, a third of these for no known reason," he said.
"The development of a reliable test for identifying these mothers is vital in ensuring our most vulnerable babies have the best possible outcomes."
The first of the remains of 250 World War I soldiers found in France are being reburied with military honours after painstaking efforts to identify them. How do you put the right name on a headstone after so long?
When the first chipped and battle-scarred bones were excavated from a muddy field in northern France last May, the story of the forgotten battle of Fromelles began to emerge.
The remains of 250 British and Australian soldiers had lain undiscovered for 93 years since falling on the Western Front.
Boots, purses, toothbrushes and other personal artefacts lay amongst the twisted skeletons at Pheasant Wood, offering partial clues about the men's identities.
But it is the unique genetic codes within these remains that offer the best chance of putting names to each unknown soldier.
So far, more than 800 UK families who think they may have lost a relative at Fromelles have given DNA samples, but many will be disappointed.
The man whose job it is to help identify the soldiers says it is like finding a needle in a haystack, albeit with a very good metal detector.
"The problem with DNA that's been in the ground for 90 years is it degrades in quality and quantity," says molecular geneticist Dr Peter Jones.
"If it's a very acidic site, there's no chance of DNA at all because acids attack DNA rapidly. If it's dry and arid like in a desert, you get good DNA. If it's wet, less good."
The remains extracted from Fromelle's muddy burial pits have produced small but workable amounts of DNA, says Dr Jones. The teeth, which preserve well because they are encased in enamel, give by far the best samples.
"The hardest part is finding the right families and getting them to come forward... you can have good DNA profiles, but no family to match it up to."
Tracing family DNA
An individual's genetic code is carried by the DNA inside every cell of the body. A unique DNA profile and sequence can be made by extracting DNA from remains of the dead or mouth swabs of the living. DNA from Y chromosomes and mitochondrial DNA is then analysed. Families will share similar DNA traits.
Family trees help establish paternal and maternal lines to trace who is alive today to provide DNA samples to match against those taken from the remains of the Fromelles soldiers. As long as a relative is on either the paternal or maternal line, then a match to a soldier should be possible.
Clues to the soldier's identity would lie with his sons or grandsons, if he had any, as the male Y chromosome DNA is passed from father to son. If he did not have children, as in the example above, DNA from his brother's grandsons or great grandsons may do.
On the soldier's maternal side, his sister's grandchildren or his sister's grandaughters' children will have inherited the same mitochondrial DNA he got from his mother. If there are no surviving members on one branch of the family, then going back generations to find another line is also valid.
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Although 250 bodies have been recovered from the graves, it's thought about 1,500 British and 5,500 Australian troops fell in the battle, making it all the harder to match.
And when it comes to matching DNA samples across several generations, Dr Jones says the methods are far from perfect.
Unlike the seven "markers" used for more exact matches on the National DNA Database, he only has two at his disposal - the Y (paternal) and mitrochondrial (maternal) profiles.
"If we had the children of the soldiers, we could use the same markers as the DNA database. But because we are three generations away, the markers get diluted out through each mother and father."
Families searching for their ancestors have been asked to give maternal and paternal samples - preferably two each - using a simple cheek swab.
The DNA results will be added to the anthropological, archaeological and historical information to try to get positive identifications.
Families will be told sometime after March, once the remains of all 250 soldiers have been buried. Their final resting place will be a new war cemetery nearby, the first to be built in 50 years.
The £3m project, funded by the British and Australian governments, is overseen by the Commonwealth War Graves Commission.
Waiting for news will be Richard Parker, 47, who has spent 25 years trying to retrace the footsteps of his ancestor Leonard Twamley. His father's uncle was just 19 when he volunteered for the Royal Warwickshire Regiment. Six months later, the 20-year-old died at Fromelles.
"He was an ordinary working class lad from Coventry working in a cycle factory, who gave his life because it was considered his patriotic duty to do so."
Although interested in Len's story since his 20s, Mr Parker did not know he was killed at Fromelles until an amateur historian contacted him last year.
Leonard Twamley's mother put this poignant notice in the Coventry Herald
Since then he has made a pilgrimage to the French village with his father, who supplied DNA, along with Len's surviving nephews and nieces.
"Even if his body isn't found, in some respects his memory is even more alive now. By researching what sort of person he was, we now know much more about him," Mr Parker says.
"My grandmother died without knowing where Len was buried... this would bring proper closure to a family tragedy that goes back 95 years."
Unknown soldiers
The bodies that remain untraceable will be buried with a headstone marked simply "Known Unto God".
Dr Jones fears many will suffer this fate. He estimates the final number identified to be up to 100, but more likely tens.
THE BATTLE OF FROMELLES
19-20 July 1916, 19 days after Somme Campaign
Intended as diversion to stop German soldiers going to Somme
Troops of 5th Australian and 61st British divisions led attack at 6pm
Within 11 hours, 5,533 Australians killed, wounded or taken prisoner and 1,547 similar British losses
Soldiers from Gloucestershire, Bristol, Warwickshire and Worcestershire heavily involved
Worst 24 hours in Australia's military history, considered a national tragedy
Forces believed to have included the then 27-year-old Adolf Hitler
Even if there is a DNA match, it may not necessarily be the right family because some DNA profiles are relatively common.
Adoptions, women who married and changed names, and paternity issues can also throw a spanner in the works. Other families simply die out.
But a match can be made through cousins, nephews or nieces on the family line. So if a family is missing a paternal link, they can trace the soldier's father, grandfather or brother, then locate their living relatives.
Dr Jones says one family went back seven generations on the maternal side then came forward five to find a suitable relative.
Forensic anthropologist Professor Margaret Cox says the team is so reliant on DNA matches as 90% of British enlistment records were destroyed in the Blitz.
And the painstaking methods of extracting and cataloguing remains have been refined at the scenes of genocide and war crimes in Rwanda, the Balkans and Iraq.
As at those sites, the bodies recovered gave clues to their fate - in this case, fractured bones showing damage from machine guns, rifles, mortar shells and shrapnel. But they were buried in deep graves with order and respect.
"You try not to imagine what it was like, it makes it difficult to do our work," she says, adding that this is easier said than done at times.
What brought the tragedy home were the artefacts - the inscribed bibles and lucky charms.
For her, the two most poignant came from Australian soldiers. The first was a small lucky charm in the shape of a boomerang, to symbolise returning home.
The other was the return half of a railway ticket from Freemantle to Perth, intended for the soldier's journey home to his family.
Scientists have found a striking similarity in the DNA that enables some bats and dolphins to echolocate.
A key gene that gives their ears the ability to detect high-frequency sound has undergone the exact same changes over time in both creatures.
The researchers report their findings in the journal Current Biology.
It may be the first time that identical genetics has been shown to underpin the evolution of similar characteristics in very different organisms.
Nature is full of cases where the path taken by evolution has resulted in the same traits, or phenotypes, developing independently in diverse animal groups.
Examples would include the tusks displayed by elephants and walruses, or the bioluminescence seen in fireflies and jellyfish.
"It's common on a morphological scale but it's assumed not to occur at a DNA level because there are so many different ways to arrive at the same solution," explained Dr Stephen Rossiter of Queen Mary's School of Biological and Chemical Sciences.
"The fact that we're able to link convergence of the DNA with a phenotype I think is unique, and in such a complex phenotype as hearing as well," he told BBC News.
Animal and human
Many bats and toothed whales like dolphins have exceptional hearing, and are able to track down their prey by emitting high-frequency noises and then listening for the echoes that bounce back.
Critical to echolocation are tiny hairs in the inner ear that move in response to sound.
Their keen performance is driven by a particular protein known as prestin, which in turn is encoded by a gene, also known as prestin.
Those bats that echolocate use high-frequency sound to track small prey
Two studies published this week in Current Biology find that this gene in bats and dolphins has picked up the same mutations over time.
"We've found a whole suite of amino acid changes that are common to these two groups that have evolved in parallel, convergently," Dr Rossiter said.
Both research teams also have evidence showing that these changes to prestin were selected for, suggesting that they must be critical for the animals' echolocation for reasons the researchers do not yet fully understand.
"The results imply that there are very limited ways, if not only one way, for a mammal to hear high-frequency sounds," said Professor Jianzhi Zhang of the University of Michigan, US, who led the other study.
This type of research is a beneficiary of the immense and ongoing effort to understand human genetics, which finds interesting targets for biologists from many fields to follow up.
Mutations in the prestin gene in humans have been shown to be associated with the loss of high-frequency hearing. It was this revelation that initiated the study of prestin's role in echolocation.
Researchers have developed a technique for precisely tracking the spread of the super bug MRSA in hospitals.
The team from the Wellcome Trust Sanger Institute in Cambridge looked at the genomes of MRSA strains from across the globe and at one hospital in Thailand.
They were able to spot small changes that allowed them to track the strain back to an individual patient.
They say this adds to the understanding of how MRSA can spread so rapidly and should lead to better treatments.
DNA sequencing
The research, which is published in the journal Science, involved teams in the UK, in Bath, Oxford and London, and Thailand, Portugal and the United States.
Scientists used new high-throughput DNA sequencing technologies to compare MRSA samples from patients to show how they were genetically related.
They were able to spot single-letter differences in the genetic code.
They looked at two different sets of samples: one set taken from people across the globe and another from a single hospital in Thailand.
They sequenced the entire genomes of each sample.
In the hospital setting it revealed single letter genetic changes in the samples showing that no two infections were caused by entirely identical bacteria.
This allowed them to discover whether one patient had infected another or whether the infection had come in from another source.
They found that the MRSA strain studied acquired about one single-letter change in its genetic code every six weeks.
Worldwide search
They also looked at samples from hospitals in several parts of the world collected over more than 20 years.
The rate of mutation apparently supports the theory that MRSA emerged in the 1960s at the time of widespread antibiotic use.
Professor Sharon Peacock, a microbiologist at the University of Cambridge said: "The implications for public health are clear. This technology represents the potential to trace transmission pathways of MRSA more definitively so that interventions or treatments can be targeted with precision and according to need."
Researchers say it would be too expensive to use the technology widely at present but the cost should fall in the next few years.
Professor Mark Enright, an expert in molecular epidemiology at Imperial College, London, said the work gave researchers "a good idea as to how this particular type of MRSA has evolved and how it behaves in and out of hospitals".
"This work is a great demonstration of new, rapid DNA sequencing that in the near future will be how important pathogens such as MRSA will be identified," he said.
"Such unambiguous identification will form the basis for rapid diagnostics of microbial infection and will tell us how they spread in hospitals identifying each human host and surface in chains of transmission between patients."
