The Scientific Breakthroughs of the Year

The December 22nd issue of Science has come out with their annual "scientific breakthroughs of the year." And it is an odd mix, partly because the top three are really confirmations.

1.
This year's top breakthrough is actually the confirmation of a confirmation. In 2002, reclusive Russian mathematitcian Grigori Perelman presented the world with what had been the Holy Grail of topology: a proof of the Poincaré conjecture. To most of us, this is obscure in the extreme. To the field of mathematics, this is a massive breakthrough. But it took 4 years for mathematicians to come to a consensus that Perelman was correct. So their confirmation of Perelman's confirmation (okay...really PROOF) of a conjecture (a mathematical statement likely to be true, but has not been formally proven to be true) from the early 20th Century.

2.
This year a pretty final confirmation of our relationship with Neanderthals was determined. After sequencing more than 1 million bases of Neandertal DNA and comparing it with the DNA of modern humans, researchers conifirmed that modern humans and Neanderthals diverged from a common ancestor who live about 450,000 years ago. This number agrees with the time of divergence determined from the fossil record and from easier to do, but less definitive mitochondrial DNA studies. For more on Neanderthals, please go here.

3. Yes, Virginia, the ice really is melting. Not too long ago I got into a respectful debate with someone on Daily Kos regarding whether the ice sheets really are melting. Well, geologists have confirmed that the world's two great ice sheets--those covering Greenland and Antarctica--are indeed losing ice to the oceans. What's worse, is that the melting is accelerating faster than earlier predictions would have expected. This is important enough to quote the article:

This disturbing breakthrough rests on decades of measurements by airborne laser altimeters and orbiting radars, and, more recently, by a pair of satellites that measure ice mass directly by its gravitational pull. Different techniques and even different analyses of the same data disagree about just how much ice volume is changing. All of them, however, now show that both Greenland and Antarctica have been losing ice over the past 5 to 10 years. In the north, Greenland is shedding at least 100 gigatons each year. In the south, the figure is less certain but lies in the range of tens of gigatons per year or more.

Current ice sheet losses aren't raising sea level faster than 0.1 meter per century, but researchers fear that the rate could rise to a meter per century or more in the near future. As recently as 5 years ago, they assumed that global warming would simply melt more and more ice from the ice sheets, as it is melting mountain glaciers. But it turns out the ice isn't just melting faster, it is moving faster. Radar mapping shows that in recent years, glaciers carrying ice away from the sheets have sped up by as much as 100%. In West Antarctica, warming ocean waters seem to have attacked the floating tongues of ice that hold back the ice sheet's outlet glaciers. Around southern Greenland, something else seems to be quickening the pace of outlet glaciers, perhaps lubrication by increasing amounts of surface meltwater seeping to a glacier's base.

4. Weighing in at #4 is a new tetrapod (that includes us) ancestor imaginatively named Tiktaalik roseae (meaning "large freshwater fish") which fills in a gap in the fossil record between fish and land animals. For more on this latest confirmation of Darwin's theory of evolution, go here.

5. Okay, THIS one is really strange! In fact, I wrote about it before: an actual cloaking device! Although the current technology only works at deflecting microwaves, theoretically it can be extended to other forms of light. But the main question Pentagon experts have is how far ahead of us the Romulans are in making a cloaking device that can hide an entire starship.

6. This one sounds mundane compared with a cloak of invisibility, but can help actual patients right now. This year the drug ranibizumab was found to improve the vision of roughly one-third of patients with one of the more serious forms of age-related macular degeneration, a form of vision loss caused by the growth and leakage of abnormal blood vessels in the retina. Prvious treatments could only slow the degeneration. For more on this disease, go here.

7. Yet another evolution related breakthrough: researchers this year have made some important discoveries on how speciation occurs on the molecular level. Very simple genetic changes in animals like mice and butterflies were shown to create differences in appearance between individuals that became barriers to reproduction, a necessary step in the divergence of species. In the case of fruit flies, another simple genetic change created varients of a protein that worked fine separately, but couldn't work together in a hybrid, again effectively blocking effective interbreeding. Once again, Darwin is proven right. For more on speciation, go here.

8. Here we have technological breakthroughs in light microscopy that allowed resolution on much smaller scales than ever before. The breakthroughs are "stimulated emission depletion" and "photoactivated localization microscopy." In the not too distant future, I just may get to play with one or more of these technologies. Then again, I haven't even had the chance to play with the current state of the art yet.

9. Coming in 9th is a subject I just heard a talk on, though it is outside of my expertise. Reserchers have made some significant steps in how the creation of memories work in the brain, focusing on the brain structure called the "hippocampus." Memory gets established through a process called "long term potentiation" wherein nerve connections become more sensitive if stimulated repeatedly over a short period of time. In essence, the current studies capture the molecular events of memories as they form. In some ways that sounds more dramatic than they really are, but they are big strides. To learn about long-term potentiation and memory, go here...if you remember.

10. Finally is a topic about something I use almost daily at work: the use of small interfering RNAs to shut down gene expression. A recent Nobel Prize went to the discoverers of this process and I use an application of it to study insulin signaling. A new version of this molecular mechanism for silencing genes has been discovered: Piwi-interacting RNAs (piRNAs). Found in the testes of some animals, including humans, piRNAs may egulate the development and maintenance of sperm cells. And it sounds like their functions could be much more widespread since there are MANY of these molecules coded for in our genes...nearly 62,000 piRNAs in rat testes. That suggests important and diverse functions. To learn more about RNA in general (RNA...it isn't just for translation anymore), .

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