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5/2/15 Cover

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Woolly mammoth DNA shows toll of low diversity

scientist with woolly mammoth tusk

Researchers extracted and analyzed DNA from ancient mammoth remains, like this tusk found by a river on the Taimyr Peninsula in Siberia, and found evidence of isolation and inbreeding just prior to the animal’s extinction.

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Even before woolly mammoths (Mammuthus primigenius) went extinct, signs of decline were written in their DNA, researchers report in the May 18 Current Biology.

The team sequenced genomes from a 44,800-year-old specimen from Siberia and a 4,300-year old specimen from Wrangel Island in Alaska, where the last known population of woolly mammoths lived out their days.

Differences between the sequences suggest that woolly mammoths hit two genetic bottlenecks: one in the middle Pleistocene around 285,000 years ago and one exclusively in the Wrangel Island population at the end of the last ice age (116,000 to 130,000 years ago). The Alaskan specimen also showed signs of low genetic diversity and inbreeding.

The researchers posit that such genetic deficits probably contributed to their subsequent demise. 

Planetary Science,, Earth

The moon is about as old as we thought it was

By Helen Thompson 6:00am, April 17, 2015
Meteorite heat signatures pinpoint the age of the collision that created the moon — confirming many previous lunar age estimates.
Astronomy,, Cosmology

Map pinpoints location of invisible dark matter

By Andrew Grant 3:05pm, April 14, 2015
A new map shows that dark matter is concentrated in regions that contain a lot of ordinary matter in the form of galaxy clusters.
Planetary Science

Atmospheric water may be giving Saturn its spots

By Helen Thompson 10:57am, April 14, 2015
Planetary scientists think that water in Saturn’s atmosphere could be driving the massive storms that appear every few decades in the ringed planet’s atmosphere.
Plants,, Science & Society

Plants suck in nicotine from nearby smokers

By Susan Milius 12:27pm, April 13, 2015
Peppermint plants can build up nicotine from tobacco dropped on their soil or smoked indoors.
Psychology

Saying ‘I’ and ‘me’ all the time doesn’t make you a narcissist

By Bruce Bower 4:15pm, April 10, 2015
People who utter lots of first-person singular pronouns such as "I" and "me" score no higher on narcissism questionnaires than peers who engage in little "I"-talk.
Genetics,, Evolution

Mountain gorilla genome reveals inbreeding

By Tina Hesman Saey 5:26pm, April 9, 2015
Mountain gorillas are highly inbred, with good and bad consequences.
Paleontology,, Ecology

Tyrannosaurs fought and ate each other

By Helen Thompson 3:23pm, April 9, 2015
Evidence from a tyrannosaur skull and jaw fossils add to the argument that the ancient reptiles fought and weren’t above scavenging their own.
Genetics,, Microbiology,, Anthropology

Mummies tell tuberculosis tales from the crypt

By Helen Thompson 4:51pm, April 8, 2015
Hungarian mummies contracted multiple strains of tuberculosis at the same time, researchers find.
Human Evolution,, Health

Natural selection may be growing taller Dutch people

By Helen Thompson 7:23pm, April 7, 2015
Over the past 200 years, natural selection may have driven the evolution of taller Dutch people, researchers posit.
Animals,, Biophysics

Distinct voices fill the fish soundscape at night

By Helen Thompson 5:54pm, April 6, 2015
Researchers find that fish sound frequencies overlap more during the day and are more distinct at night.
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