Top 5 discoveries of 2010…
I haven’t come across any particularly interesting articles in the last few days, so in light of the fact that this blog has only been operating for a couple of months I thought I would post my personal top 5 moments in science from last year. Being something of an evolutionary anthropology nut it will of course have something of a lean in that direction. Let’s see what you think.
Number 5: Hey ragworm brain!
Not as insulting as it sounds. Research headed by molecular biologist Raju Tomer published in Cell last year demonstrated that the ‘oh so special’ human cerebral cortex isn’t really all that different from the brain of the lowly ragworm, an organism that appeared some 600 million years ago. This was determined through gene expression based brain cell mapping that showed striking similarities between our brains and those of the mentioned invertebrate. It was long thought that the evolution of the complex vertebrate cerebral cortex was the result of evolutionary pressures like predation that required complex behavioral responses, this paper would beg to differ.
The marine ragworm: certain team-mate at my next quiz night.
Number 4: Ancient AIDS
It is agreed upon by many scientists that the most likely source of the human immunodeficiency virus (HIV) was a closely related primate virus known as the simian immunodeficiency virus (SIV) that evolved to be capable of human infection some time in our recent history. What wasn’t known is just how old SIV is and just how long it has existed in primate populations alongside human populations without crossing over. Virologist Preston Marx, via a study of SIV in monkeys from an island cut off from the African mainland some 10,000 years ago, has suggested that the virus present in these monkeys shares a common ancestor with that of the virus found in modern African primates. This suggests that SIV is at least 10,000 years old and that humans have coexisted with primates infected with this virus without issue until relatively recently.
Number 3: What color is your Sinosauropteryx?
Not anthropological, but very interesting. Paleontologist Mike Benton set out to prove that the spiny hairs visible on the fossilized remains of a 125 million year old dinosaur were the precursors of feathers but discovered something of much greater consequence. Microscopic examination of the spiny hairs revealed melanosomes which allowed Benton to ascertain what color part of the coat of this particular Sinosauropteryx had been. It turns out that the little dinosaur possessed a striped dark red/brown and white tail. This is the first real evidence we have of the coloration of dinosaurs.
Sinosauropteryx: no imagination required.
Number 2: My grandpappy was a Homo neanderthalensis. Seriously.
In mid 2010 a group of scientists, making use of the growing body of knowledge about the H. neanderthalensis genome, announced that it is highly likely that interbreeding occurred between early Homo sapiens (prior to their move into Europe) and our Neanderthal neighbors. This conclusion was reached after it was found that many humans alive today carry between 1 and 4 percent Neanderthal genes. I don’t need to explain why this was in my top 5. It may surprise you that it wasn’t number 1…
H. neanderthalensis: Not what most people have in mind when they think of geneology.
Number 1: The mysterious Denisova hominin
March 2010 saw the discovery of a Homo tooth and finger bone in Russia that pointed to something very interesting (pardon the pun). Dating of the finger bone suggested that the individual occupied the same temporal space (~41,000 years ago) as Homo sapiens, Homo neanderthalensis and Homo floresiensis. Analysis of genetic material within these finds yielded a few discoveries of great importance. Firstly, the mitochondrial DNA indicated that the individual was of a previously unknown maternal lineage, suggesting a species that to that point had been unknown. Secondly, the nuclear DNA suggested a shared common ancestor with Neanderthals AND interbreeding with the ancestors of modern Melanesians. This discovery combined with the discovery of interbreeding between Neanderthals and Homo sapiens (see above) paints a new and very different picture of the history of the genus Homo. Bit of a tangent here, but this discovery reinforces that which I have always said about taxonomy; it isn’t as useful as it seems. Especially when speaking of intermediate forms and technically speaking, all life forms are intermediates, forms between some point in the past and another in the future (extinction excepted). Up to four Homo (or at least Homo like in the case of floresiensis) species, three of which are capable of interbreeding (or at least were in the past), existing at the same time. Were they really different enough to be considered distinct species? Sub-species? See what I mean? Semantics! Either which way, very exciting finds. I look forward to hearing more about Denisova and related work.