Saturday, November 23, 2013

Weekly Science Roundup #23

And we're back! It's Weekly Science Roundup time!

1. Martian Meteorite Shows Off Oldest Surface of Mars

Ancient Mars, Artist Rendition (Ittiz)
A meteorite found in the Sahara desert has not only been shown to originate from Mars, but actually includes within it a chunk of the ancient Martian crust from 4.4 billion years ago. Whoa! This is the oldest piece of Mars scientists have ever had the chance to study!

Already it's proven interesting, showing possibly ten times more water than has been found in any other Martian sample. And in reassuring news, it shows a similar composition as to what our Mars rovers have shown in their own sampling from the surface of Mars proper.

This is such a rare find, that it's estimated that to purchase even a gram of this meteorite would cost $10,000 or more. It's kind of a big deal.

2. Human DNA Wackiness

Lots of DNA-based news this week. First off, Native American genomes. Based on previous research, it had been presumed the first Americans that crossed over from Siberia and populated the Western hemisphere were originally East Asian in origin. Now, new bones from Siberia show that while a good chunk of Native American DNA does have East Asian ties, about a third of it is actually from Western Eurasian people. This might help explain some as-of-yet-remaining mysteries in the genomes of Native American populations. It also begs the question as to whether this influx of Western DNA happened in Siberia or if it actually happened in America from multiple migration events. Hmm.

This week, we've also broken further into the study of viruses encoded in our DNA. Long story short on this one, viruses sometimes wind up in our DNA, getting copied and passed down generation to generation. Researchers have discovered some of these viruses actually came from the Neanderthal portion of our DNA, and also the Denisovan portion (another group of ancient people that we interbred with). That's about half a million years ago that this stuff got lodged in our genome. And it might prove insightful for understanding modern diseases, like AIDS and even various forms of cancer. This is really cool stuff to keep your eyes peeled for. Big things could come of this.

Speaking of Denisovans, though, in a third study released this week, it's shown that not only did Denisovans interbreed with us, and with Neanderthals...they also interbred with yet another ancient group of people that is neither human nor Neanderthal. No ones knows who this mystery group might be, but they existed about 30,000 years ago in Asia. Perhaps it is one of the fossil species we haven't sequenced yet, like Homo heidelbergensis. Though keep in mind, in light of other recent findings, these varying groups might not be as distinguished as true species, but rather as isolated populations of humans. One researcher phrased this as a Lord of the Rings type scenario--one world with many different types of peoples. Except at least some of the time, this ancient world was clearly taking the motto, "Make Love, Not War" to heart far more than in the Lord of the Rings universe.

3. Happy 15th Anniversary, ISS!

This week, the International Space Station hit its 15th anniversary! On November 20th of 1998, the first piece of the station launched from Earth. Today, modern science and technology have both benefited enormously from this international effort. I'm wrapping up this week's roundup with NASA's congratulatory video. Here's to many more productive years at the ISS!

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