Dingoes, the yellow native dogs of Australia, probably evolved from a very small group of pets brought by southeast Asian settlers, researchers reported Monday.
"The dingo originated from a population of east Asian dogs," said Peter Savolainen of the Royal Institute of Technology in Stockholm. Genetic tests show the animals' ancestry dates back 5,000 years.
Researchers collected DNA samples from 211 dingoes and compared them to the DNA of 676 dogs worldwide and 38 wolves from Europe and Asia.
The researchers looked specifically at mitochondrial DNA, a genetic material passed down with few changes from mothers to daughters. The material suggests how long ago - and even from where - a species evolved. All the mitochondrial DNA sequences among the dingoes were either identical or off by only a single letter of the sequence, the researchers reported.
Dingo remains date back about 3,500 years, they added, and no dingoes were found on Tasmania, which separated from the rest of Australia about 12,000 years ago.
With water increasingly scarce in its parched, heavily populated northeastern plain, China has become the world's leading rainmaker, using airplanes, rockets, and even antiaircraft guns to seed the clouds. The hunt for rain has become so intense that rival regions sometimes compete for clouds sailing across the sky.
Provincial, county, and municipal governments in 23 of the country's 34 provinces have set up weather modification bureaus to regularly bombard the heavens with silver iodide or liquid nitrogen in hopes of squeezing out more rainfall for demanding farmers and thirsty city dwellers among China's 1.3 billion residents.
As do their counterparts elsewhere, Chinese rainmakers seed clouds to produce ice crystals, which fall as rain in the warmer air below. Such science is widely known, said Hu Zhijin of the Weather Modification Research Center at Beijing's Chinese Academy of Meteorological Science. But because of its severe weather problems, China has used the know-how more often than other countries. So far, he added, no signs have emerged that frequent cloud seeding harms the environment.
Hu noted that China's rainmakers produce only a 10 to 15 percent increase in rainfall. In addition, he said, the vagaries of nature, such as wind direction and velocity, make the effect of cloud seeding difficult to predict.
Wildlife biologists in Sri Lanka say they have confirmed for the first time the existence of a long-fabled white elephant.
The albino elephant, a female believed to be about 11 years old, was observed in mid-July in a herd of about 17 adult females and young elephants in Yala, Sri Lanka, according to Wildlife Trust of Palisades, N.Y., and the Centre for Conservation and Research of Colombo, Sri Lanka, two conservation groups.
Researchers from the groups have studied elephant ecology and behavior for the past 12 years to determine how the country's 3,500 elephants survive in the midst of Sri Lanka's agricultural expansion.
Although there have been reported sightings of white elephants in Thailand and other countries, this marks the first time the existence of a true albino elephant has been confirmed, according to Mary Pearl, president of the Wildlife Trust.