A cloned pig whose genes were altered to make it glow fluorescent green has passed on the trait to its young, a development that could lead to the future breeding of pigs for human transplant organs, a Chinese university reported.

The glowing piglets' birth proves transgenic pigs are fertile and able to pass on their engineered traits to their offspring, according to Liu Zhonghua, a professor overseeing the breeding program at Northeast Agricultural University.

Robin Lovell-Badge, a genetics expert at Britain's National Institute for Medical Research, said the technology "to genetically manipulate pigs in this way would be very valuable."

Lovell-Badge had not seen the research from China's cloned pigs and could not comment on its credibility. He said, however, that organs from genetically altered pigs would potentially solve some of the problems of rejected organs in transplant operations.

A Houston-area man was killed in a hunting accident after his dog stepped on a loaded shotgun in the back of a pick-up truck, triggering a blast that pierced the vehicle and the hunter's leg, a local sheriff said.

Perry Price, a 46-year-old math teacher, shot a goose on Saturday then put his gun in the back of the truck where the dog was waiting to retrieve the bird.

"I've been in law enforcement 20 years and this is probably the strangest one I've had," said Chambers County Sheriff Joe LaRive.

Selling sex is said to be humankind's oldest profession but it may have deep evolutionary roots, according to a study into our primate cousins which found that male macaques pay for intercourse by using grooming as a currency.

Michael Gumert of Nanyang Technological University in Singapore made the discovery in a 20-month investigation into 50 long-tailed macaques in Kalimantan Tengah, Indonesia, New Scientist reports on Saturday.

On average, females had sex 1.5 times per hour.

But this rate jumped to 3.5 times per hour immediately after the female had been groomed by a male -- and her partner of choice was likely to be the hunky monkey that did the grooming.

If there were several females in the area, the cost of buying sex would drop dramatically -- a male could "buy" a female for just eight minutes of nit-picking.

But if there were no females around, he would have to groom for up to 16 minutes before sex was offered.

"There are many examples of rich old men getting young attractive ladies."