Straight ahead on "Our World" ... Plucking DNA samples from the hair of extinct animals ... the health benefits of drinking tea ... and deformed frogs, parasites, and the environment ...
JOHNSON: "So we know that parasites can often kill large numbers of frogs, but what the long-term consequences of that are for amphibian population declines still remains largely unexplored."
Those stories, a Space Age anniversary, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
Recreating dinosaurs and other long-extinct species from their DNA is the stuff of science fiction, but ancient DNA may be easier to recover and study thanks to new research published this week. An international science team was able to unlock the genetic blueprint of extinct Siberian woolly mammoths from samples of their hair, using a technique that is easier and cheaper than extracting the DNA from bone. VOA's Jessica Berman reports.
BERMAN: Scientists mapped the entire DNA sequence from the hair shafts of 13 Siberian woolly mammoths.
The mammoths roamed the earth 30,000 to 60,000 years ago and are the common, prehistoric ancestor of the African and Indian elephants.
The hair in the study was obtained from a frozen mammoth found in 1799 in the permafrost near Siberia.
For the past 200 years, the hair remains were stored at room temperature at the Zoological Museum in St. Petersburg.
Stephan Shuster is with the Center for Comparative Genomics at Pennsylvania State University.
Shuster, who is part of the international team that sequenced the genetic material taken from the hair samples, says no one thought it was possible to derive usable DNA.
SHUSTER: "All of us would have predicted that just the fact that ... it was not kept frozen or at least refrigerated would have destroyed every remaining DNA that was in that bone or in that hair. But in our study we can show, no, this old one worked, not only worked, but in this smallest amount of hair that we had."
BERMAN: Shuster says it is possible to obtain DNA from dinosaur bones. That is how paleontologists know as much as they do about the age of the creatures and their evolutionary history.
But he says DNA analysis of dinosaur bones is expensive and difficult. DNA analysis of hair, on the other hand, is quite simple and relatively inexpensive, according to Shuster.
SHUSTER: "It is kind of like a biological plastic. And the contaminating bacteria and fungi is sitting on the outside of the hair. And so, we can bleach, like in the laundry machine, we can bleach the outside of the hair, and the DNA on the inside stays intact. And so after we remove the contaminating bacteria, we then dissolve the bacteria from the hair and then isolate very pure mammoth DNA from it."
Shuster says the hair analysis can be performed on samples as small as a single strand. And he says researchers found usable DNA along the entire hair shaft, not just the hair root closest to the mammoth's skin.
Shuster expects the finding will tell researchers a lot about the evolution of elephants.
SHUSTER: "This gives you a very good time for determining the time that the living elephant, the Indian elephant and the African elephant, how long it took them before they separated and the last common ancestor of the two."
BERMAN: The study describing DNA analysis of woolly mammoth hair is published in the journal . Jessica Berman, VOA News, Washington.
We humans like to think of ourselves as vastly superior to the rest of the animal kingdom, but in a lot of very basic ways, we're really not so different. For example, the way we choose a mate. Social position, physical appearance, intelligence are part of it. And now, as we hear from health reporter Rose Hoban, new research indicates that humans may prefer partners with certain vocal qualities.
HOBAN: Harvard University Anthropologist Coren Apicella spent time living with and studying a small tribe in Tanzania called the Hadza.
APICELLA: "This is one of the last hunter-gatherer populations that practiced traditional foraging and hunting techniques that are left on the planet. And they're really great to study because they provide sort of a window to our past. They live just like we would have lived, our ancestors would have lived about 200,000 years ago."
HOBAN: The Hadza do not use any form of modern birth control, so Apicella says they're a good population to study if you want to look at the reproductive outcomes of certain behaviors. She recorded the voices of about 50 men and 50 women and then questioned all of them about their reproductive histories.