Scientists have discovered a genetic mutation that appears to make certain dogs, like labrador retrievers, extra motivated by food and treats and also more likely to be obese.
The report in the journal Cell Metabolism is the first to identify a gene associated with canine obesity.
"We've found something in about a quarter of pet labradors that fits with a hardwired biological reason for the food-obsessed behaviour reported by owners," said lead author Eleanor Raffan, a veterinary surgeon and geneticist at the University of Cambridge.
Researchers first identified the variation, which occurs in a gene called POMC, in a group of dogs that included 15 obese and 18 lean labrador retrievers.
The obese dogs tended to have a section of DNA that was scrambled at the end of the gene, with the effect of hampering the dog's production of brain chemicals which tell the body it is no longer hungry after a meal.
Water on Mars? Yes!
The results of Earth-bound lab experiments appear to back up the theory that dark lines on Martian slopes are created by water - though in an otherworldly manner.
A team from Britain, France and the US built models and simulated Mars conditions to follow up on a 2015 study which proffered "the strongest evidence yet" for liquid water - a prerequisite for life - on the Red Planet. That finding had left many scientists puzzled as the low pressure of Mars' atmosphere means that water does not survive long in liquid form. It either boils or freezes.
For the study, the team placed a block of ice on a 30-degree plastic slope covered with loose fine-grained sand, and allowed it to melt in a chamber in which Martian pressure and summer temperature was recreated. They found that melting ice produced a liquid which boiled vigorously as it flowed downslope and filtered into the sand. The evaporating water vapour blasted grains upward, creating ridges which collapse onto themselves when they become too steep, forming channels.
The 'ageing' gene
It is no secret that good genes can explain why some people age well. But researchers say they have identified a specific gene variant that can make people look about two years older than their actual age.
Scientists already know the gene in question - MC1R - is responsible for producing red hair and pale skin, said the report in Current Biology. But now they have identified a variation in this gene that seems to age people faster.
"For the first time, a gene has been found that explains in part why some people look older and others younger for their age," said researcher Manfred Kayser of Erasmus MC University Medical Centre Rotterdam.
For the study, scientists examined the genomes of more than 2,600 elderly Dutch Europeans "for DNA variants associated with differences in perceived facial age and wrinkling as estimated from digital facial images", the report said. "The strongest hits for perceived facial age were for DNA variants in the MC1R gene."
The influence of the MC1R gene variant was not swayed by age, sex, skin colour or sun damage. MC1R is also known for its role in inflammation and DNA damage repair.