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Dog Hair May Provide Insight on Cancer

Posted by jase on August 27, 2009

Scientists have located the genes that make a poodle’s hair curly, and a collie’s hair long and straight.

No, this wasn’t just a way to ease the boredom of laboratory work, but part of a long-term project to figure out how genes cause disease.

The coats of domestic dogs vary widely — they can be long, short, straight, wavy, curly, wiry, smooth or a combination of different varieties. And that difference is exactly why cancer geneticist Elaine Ostrander decided to study dog hair.

Ostrander, who works at the National Human Genome Research Institute, wanted to know how genes create all this variety. So she studied about 1,000 dogs from about 90 different breeds.

She searched dog DNA the way a chef might compare recipes for souffle. What changed ingredient makes one different from the next? What mutation gives an Airedale terrier his curls and a golden retriever her tresses?

A Three-Gene Recipe

What Ostrander and her team discovered was that only three genes control all the different kinds of dog hair.

“You can go to the dog park, and every breed of dog looks different from every other breed, it seems,” says Ostrander. “Yet, you know, when we get down to the molecular biology, we really find that it’s a combination of three different genes that accounts for all that variation.”

This also has value in studying disease. Human and dog cancers are similar, so the fact that only three genes can create so much variation in hair might provide clues to how genes cause so many cancers in dogs and humans.

“Whether or not the exact same gene is mutated in humans doesn’t really matter,” says Ostrander. “It’s telling us the pathways that are involved, the kinds of genes that are involved, and the kinds of changes in those genes that lead to those diseases.”

The research appears online Thursday in Science Express.

Source: NPR

Posted in Animals, Biology, DNA, Science | Tagged: , , , , , | Leave a Comment »

350 Year Old Photo Uncovered of Dodo Before It was Extinct

Posted by jase on July 7, 2009

A previously undiscovered 17th century picture of a dodo, drawn before the bird became extinct, is to be sold at auction by Christie’s.

The drawing, which dates from the late 1600s, offers a rare insight into the appearance of the flightless bird that was the first recorded casualty of human interference in the habitat of other creatures.

Dodos were the main predators on Mauritius until settlers introduced bigger animals to Indian Ocean island, including pigs. Many were shipped to Europe as curiosities or had their nesting areas destroyed and the species was extinct by 1700.

The 350-year-old drawing, described by Christie’s as “vibrant”, is one of a small number of images of the unfortunate bird whose demise was largely unnoticed until a dodo featured in Lewis Carroll’s popular 1865 book Alice’s Adventures in Wonderland.

Painted by an unknown artist of the 17th century Dutch school in about 1650, the unframed 10×8 inch picture is expected to fetch up to £6,000 when it is sold by Christie’s in London on July 9.

The auction house believes it differs from existing images, many of which were drawn from a small number of dodos that were put on display in Europe, some of which were later stuffed.

Little is known about the origin of the picture, which has never before been published.

The inscription above the bird, ‘Dronte’, was the Dutch 17th-century name for the dodo, although at this period it was also used in a number of other languages including French, German and Italian.

Julian Hume, a dodo expert and a palaeontologist at the Natural History Museum, said the image was “very interesting but rather odd”.

“The lack of tail is anatomically correct – the ostrich-like plumes normally depicted are exaggerations – but this may be a fault by the artist,” he said. “The angle of the dodo is also novel, showing a 3D pose rather than the usual side view.”

He added that it was likely to have been copied from earlier drawings. “The image is somewhat based on Roelandt Savery’s 1626 image of the dodo standing by a rock. We know so little about the number of transported live dodo specimens, and coupled with repeated plagiarism of images, factual determination is almost impossible to obtain.”

Another dodo expert, Anthony Cheke, said: “There is always a lot of interest in artefacts like these because the dodo is such a curiosity. This is certainly an unusual image although the drawing is, frankly, not very good even by contemporary standards.”

Posted in Animals, extinction | Tagged: , , , , , , , | 1 Comment »

Global Warming Shrinking Sheep

Posted by jase on July 6, 2009

Changing winter conditions are causing Scotland’s wild Soay sheep to get smaller, according to a study that suggests climate change can trump natural selection.

The authors of the study published in “Science” believe that it highlights how wide-ranging the effects of global climate change can be, adding further complexity to the changes we might expect to see in animal populations in future.

“It’s only in the last few years that we’ve realized that evolution can influence species’ physical traits as quickly as ecological changes can. This study addresses one of the major goals of population biology, namely to untangle the ways in which evolutionary and environmental changes influence a species’ traits,” said Andrew Sugden, deputy and international managing editor at Science.

The researchers analyzed body-weight measurements and life-history data for the female members of a population of Soay sheep. The sheep live on the island of Hirta in the St. Kilda archipelago of Scotland and have been studied closely since 1985.

They selected body size because it is a heritable trait, and because the sheep have, on average, been decreasing in size for the last 25 years.

According to the findings lambs are not growing as quickly as they once did as winters have become shorter so do not need to put on as much as weight in the first months of life to survive.

The results suggest that the decrease is primarily an ecological response to environmental variation over the last 25 years. Evolutionary change, the report says, has contributed relatively little.

“Sheep are getting smaller. Well, at least the wild Soay sheep living on a remote Scottish island are. But according to classic evolutionary theory, they should have been getting bigger, because larger sheep tend to be more likely to survive and reproduce than smaller ones, and offspring tend to resemble their parents,” said study author Tim Coulson of Imperial College London.

“Our findings have solved a paradox that has tormented biologists for years — why predictions did not match observation. Biologists have realized that ecological and evolutionary processes are intricately intertwined, and they now have a way of dissecting out the contribution of each. Unfortunately it is too early to tell whether a warming world will lead to pocket-sized sheep,” said Coulson.

Posted in Animals, Biology, Climate, Earth, Global Warming, Science | Tagged: , , , , , , , , | 1 Comment »