Archive for the 'Molecular Biology' 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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Evolution in Action by AMNH

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This video tells the story of speciation in Central Africa's roiling, rapid Lower Congo River. This river is home to an extraordinary assortment of fish -- many truly bizarre. This new video by Science Bulletins, the American Museum of Natural History's current-science video program, features Museum scientists on a quest to understand why so many species have evolved here. Follow Curator of Ichthyology Melanie Stiassny and her team as they search the Lower Congo River's mysterious depths for an evolutionary driver.

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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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Made for Each Other: Evolution of Monogamy in Poison Frogs

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Peruvian mimic poison frog, Ranitomeya imitator.
Image: Jason Brown [larger view]

To know the breeding system is to know the genetic architecture of a species.
To know the evolution of a breeding system is to know how evolution works ..

~ Lewis & Crowe, Evolution (1955)

Genetic tests have revealed the secret sex life of a tiny poison dart frog species that lives in the Peruvian rain forests: remarkably, it turns out that these frogs are monogamous. But the reason this species is monogamous is surprising: it's all about the size of the pools that their tadpoles mature in. This is the best evidence yet that just a single cause can affect evolution of a major life history trait, such as a species' mating system.

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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.

This post was chosen as an Editor's Selection for

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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LavaAmp: The Amazing Handheld Thermal Cycler

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Millions of people in the Global South suffer from neglected diseases, many of which could be treated, even cured, if they were detected early enough. But reliable, low cost diagnosis hasn't been available, as drug companies have no incentive to invest in the diseases of the poor. New pandemics can go undetected until they have spread out of control, like HIV, and treatable ailments can cripple impoverished communities because it is too expensive to detect them early enough to do something.

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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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