Archive for the 'Genetics' category

The Mystery of the Family That Walks on All Fours

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This fascinating video is a complete episode of the American science program, Nova. This episode is about a Turkish family where all the children -- who are adults -- walk on all fours. This episode, which started out as an exploration of the neurobiology and genetics behind this curious behavior turned into a touching human story about a family trying to deal with a devastating disability.
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The World's Smallest Horse

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The world's smallest horse, a colt named Einstein, was born 22 April 2010 on a farm in Barnstead, New Hampshire. Just 14 inches tall and weighing only 6 pounds at birth, Einstein appears to have beaten the previous "world's tiniest horse" record holder by three pounds. This raises the question: how small can humans force horses to evolve through selective breeding? Apparently, pretty damned small, according to equine geneticist Samantha Brooks of Cornell University, who asserts that there may be no limit to how tiny we can make our horses.

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What do Great Tits Reveal about the Genetics of Personality?

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Bold or cautious? Individuals with a particular gene variant are very curious --
but only in some populations.
Image: Henk Dikkers.

Research suggests that personality variations are heritable in humans and other animal species, and there are many hypotheses as to why differences in personality exist and are maintained. One approach for investigating the heritability of personality lies in identifying which genes underlie specific personality traits so scientists can then determine how the frequencies of specific variants of personality-related genes change in both space and time as well as in relation to changing environmental influences.

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Gender-Bending Chickens: Mixed, Not Scrambled

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Almost exactly one year ago, hundreds of American birders
were thrilled by sightings and photographs of this remarkable
Northern Cardinal, or Redbird, Cardinalis cardinalis,
photographed in Warrenton, VA.
Image: DW Maiden, 2 March 2009.

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I'll never forget the first time I saw a bilateral gynandromorph. I was a bird-crazy teenager reading my way through a stack of avicultural publications when I spied the strangest bird I'd ever seen on the cover of one magazine: an eclectus parrot that was very precisely divided down the middle: one side was rich scarlet and the other was brilliant emerald. Because eclectus parrots are sexually dimorphic -- females are red and males are green -- this remarkable bird was easily identifiable as being composed of both sexes, one on each side.

Even though this was the first time I'd ever seen a gynandromorph, these mysterious birds do pop up from time to time. For example, bird watchers occasionally run across them in the wild (see above photograph) and poultry farmers sometimes find them in their flocks: it is estimated that roughly one in 10,000 domestic chickens -- another sexually dimorphic species -- is a gynandromorph.

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Ancient DNA from Fossil Eggshells May Provide Clues to Eggstinction of Giant Birds

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Elephant bird, Aepyornis maximus, egg
compared to a human hand with a hummingbird egg balanced on a fingertip.

To conduct my avian research, I've isolated and sequenced DNA from a variety of specimens, such as blood, muscle, skin and a variety of internal organs, dry toepads from long-dead birds in museum collections, feathers, the delicate membranes that line the inside of eggs, and even occasionally from bone. But I was surprised to learn that avian DNA can also be extracted directly from fossilized eggshells -- eggshells that completely lack eggshell membranes.

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Racehorse Research Identifies Speed Gene

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Emerging from the mist is Rachel Alexandra, a champion American Thoroughbred who excels at winning both long and short distance races.
Image: Rob Carr, 2009, Associated Press [larger view]

If you've worked at or been around a racetrack very much, as I have, you'll quickly realize that everyone there has their own pet idea for picking winners. Horse breeders rely on pedigree analysis and studying the horse's conformation to predict whether a particular racehorse is better suited for running short or longer distances. But this is an art that requires both practice and experience and it can waste valuable time, money and sometimes, horses. Which makes one wonder whether modern science can be applied to the challenge of identifying specific genes that make a particular horse better suited to running sprints or distances?

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Migratory Monarch Butterflies 'See' Earth's GeoMagnetic Field

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Every autumn, millions of monarch butterflies, Danaus plexippus, each weighing less than one gram (one US penny weighs 2.5 grams), migrate nearly 4000 kilometers (3000 miles) between their summer breeding grounds in the United States and their wintering areas either in southern California or in the mountains of Mexico (Figure 1).

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Bacteria Make Mexican Waves

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By synchronizing our clocks, we can coordinate our activities with people around the world. Now, scientists have genetically engineered bacteria to synchronize their molecular timekeepers, creating the stunning fluorescent waves that you see in this video (this video shows new research published today in NATURE).

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Cotton: Building a Better Plant

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This is another beautifully written and produced video about plant research. The lucky plant? This time, it's cotton -- what jeans and t-shirts are made of! This video explores how modern cotton plants came to be, the 50 species of cotton, and how cotton genomic research can improve our lives.

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Corn: The Dynamic Genome

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This is a beautifully written and produced science video about corn: where it came from, what it originally looked like, the technology we are using to learn the functions of individual corn genes, and future directions for research into corn genetics.

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