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Genetics Show How Prehistoric Cultures Migrated & Shared Knowledge

Thu, 07 Aug 2008 15:14:24 GMT

clipped by: Mohir
clipper's remarks: The researchers tracked genetic variation on the Y chromosome, the sex chromosome passed from father to son that encodes maleness, using a technique now widely used that was developed in the early 1990s by Underhill and colleagues in the lab of Luigi Cavalli-Sforza, professor emeritus of genetics. The method has given scientists a powerful window into ancient human migrations and prehistoric cultural shifts. The technique has also been adopted by some commercial genealogy services that offer Y-chromosome testing to the public.

Clip Source: www.dailygalaxy.com

Using a genetic technique pioneered at Stanford, a research team found that animal-herding methods arrived in southern Africa 2,000 years ago on a wave of human migration, rather than by movement of ideas between neighbors as previously believed.

Prior research suggested that prehistoric people in eastern and southern Africa had little contact, with only two known migrations between the regions about 30,000 and 1,500 years ago. After Bantu-language speakers migrated from eastern to southern Africa 1,500 years ago, agriculture took off in southern Africa. But the timing of the Bantu migration didn't quite match the 2,000-year-old anthropological evidence for the first sheep and cattle herds in southern Africa, so anthropologists were unsure whether the region's agricultural knowledge came from a wave of ideas that spread in front of the migrating Bantu, or whether a separate migration brought the first herders.

Tags: genetics

Neurobiologists Discover Individuals Who 'Hear' Movement

Thu, 07 Aug 2008 13:25:49 GMT

clipped by: Silkweaver
clipper's remarks: "We might find that motion processing centers of the visual cortex are more interconnected with auditory brain regions than previously thought, even in the 'normal' brain," Saenz says. "At this point, very little is known about how the auditory and visual processing systems of the brain work together. Understanding this interaction is important because in normal experience, our senses work together all the time."

Clip Source: www.sciencedaily.com

Individuals with synesthesia perceive the world in a different way from the rest of us. Because their senses are cross-activated, some synesthetes perceive numbers or letters as having colors or days of the week as possessing personalities, even as they function normally in the world.

Now, researchers at the California Institute of Technology have discovered a type of synesthesia in which individuals hear sounds, such as tapping, beeping, or whirring, when they see things move or flash.

Surprisingly, the scientists say, auditory synesthesia may not be unusual--and may simply represent an enhanced form of how the brain normally processes visual information.

Psychologists previously reported visual, tactile, and taste synesthesias, but auditory synesthesia had never been identified.

Caltech lecturer in computation and neural systems Melissa Saenz discovered the phenomenon quite by accident.

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Genetics Show How Prehistoric Cultures Migrated & Shared Knowledge

Neurobiologists Discover Individuals Who 'Hear' Movement

* Bridges in Europe

Bridge of Sighs, Venice

Ponte Vecchio, Florence

Tower Bridge, London

Charles Bridge, Prague

Oresund Bridge (Öresundsbron)

The Old Bridge, Mostar

Széchenyi Chain Bridge, Budapest