Wednesday, August 15, 2012

The Neanderthal Genome Project

The majority of the DNA used for the Neanderthal
Genome Project was obtained from the bone fragments
of three females who were excavated from the Vindija
Cave in Croatia. Image: Max Plank Institute for
Evolutionary Anthropology/Frank Vinken.

Found in Europe and parts of Asia, Neanderthal lived from about 400,000 years ago until 30,000 years ago. Neanderthals were comparable in size to Homo sapien, but more robust. They also had similar brain sizes, but their skulls were shaped differently. Researchers have long wondered why Neanderthal went extinct. Some think the lack of genetic diversity made it too hard to persevere through plagues while others think that their smaller, less sophisticated social groups played a part in their demise. We do know that their stronger build would have required more food which would have been a disadvantage during hard times.
   In 2010, scientists from the Max Plank Institute for Evolutionary Anthropology in Germany reported that they had completed a first draft of the Neanderthal genome. This research was based on analysis of four billion DNA base pairs. Through DNA analysis, we have learned insights that had been previously unknown through only fossil evidence. Their study suggests Neanderthals had an effective population smaller than that of modern humans, and lived in small, isolated groups. And although we share about 99.7% of the same DNA, only 1-4% of modern non-African humans have inherited DNA from Neanderthals, and Africans have no common lineage. Most likely, the interbreeding occurred early in the migration of humans out of Africa.

   DNA analysis has also proven fruitful in a recent discovery in a cave in Northern Spain. Researchers there found the butchered remains of an extended Neanderthal family that were killed and eaten by other Neanderthals. The bones were cracked open by stone tools for marrow, suggesting that they were cannibalized before the cave collapsed and buried their remains. Researchers found that the group was genetically very similar, confirming that Neanderthals had less genetic diversity than modern humans. They also discovered through DNA analysis that they lived in small groups of males that were closely related, and that the females came from other tribes, a social system called patrilocality. Clearly, our understanding of human evolution is benefitting greatly from DNA analysis.

Monday, August 6, 2012

NASA Takes Gold in the 567 Billion Meter Dash!

The first image taken by the NASA Curiosity rover after
the dust covers were removed from the cameras.

I watched in amazement last night as NASA pulled off a perfect landing to put Curiosity—the most complex rover ever built—on the Martian surface. Congratulations to all the hard-working men and women at NASA/JPL for not creating a 2.5 billion dollar crater instead! If they were terrified during those seven minutes from when Curiosity entered the Martian atmosphere travelling 20,000 kph until touchdown, I sure could not tell. Nothing but professionalism and ear to ear grins and high fives once it had landed. 
   Curiosity weighs in at 900 kg and is three meters long, larger than some small cars. It is equipped with 80 kg of instrumentation, including a variety of cameras and a laser that is powerful enough to vaporize rock. These are the most-advanced instruments ever used on the Martian surface. Curiosity will be able to determine mineral and soil composition, atmospheric processes, detect chemical biosignatures and characterize the surface radiation on Mars.
   The Mars Science Laboratory’s goals for this mission are to search Mars for signs of life, past or present, study the climate and geology of Mars, and plan for a future manned mission to Mars. The mission is scheduled to last for about two years, but if conditions are favorable, the rover could be in operation for much longer.
   In the weeks and months to come I will be writing more about this incredible mission and its discoveries. In the meantime, to celebrate NASA/JPL’s successfully landing, this week’s quiz is about Mars. See how much you know about the Red Planet.