Nobody who follows the scientific literature can possibly have missed the reports on Craig Venter’s metagenomics effort, trawling the oceans on his “Sorcerer II” yacht on the search for new DNA sequences. Unlike some of my fellow bloggers who know their metagenome, I have never been quite convinced that metagenomics is good for anything (except maybe for yachting on grant money).
This notion has changed today, when at around 2 pm CET, people in my group made an earth-shattering discovery while analysing some portion of the global ocean sampling data. It appears that the book on primate biology has to be re-written, or in other words, by overturning a century-old dogma, primate science is experiencing a veritable paradigm shift. To put our epochal discovery into context: Until recently, the smallest known primates were probably the pygmy mouse lemur (microcebus myoxinus), maybe this guy here. With a weight of 30-70 grams, and a length of 10-14 centimeters, these primates are firmly anchored within the macroscopic realm. However, as we have learned now, there is at least one more species of primates, living in the oceans, which has eluded us due to its small size.
By using most advanced computing hardware (HP dc7700) and software technology (BLAST), we were able to show that at least 1090 different sequences from various oceanic regions contain Alu elements, which are a hallmark of the primate genome. Our first suspicion was that the trawling device inadvertently sampled a Scuba diver, who did not manage to escape the subsequent homogenization step. However, this theory had to be abandoned, as i) the ocean sample sequences did not yield a perfect match to the human genome, ii) there was no homogenization step, and iii) the sampling procedure described in the original publication was selective for the size range of 0.1–0.8-μm, which does not accommodate divers.
Thus, we are currently pursuing alternative explanations, the most likely of which is the existence of a hitherto unnoticed ocean dwelling micro-primate. While our analyses are still ongoing, the results obtained so far fully support this theory. Not only are the ocean-derived Alu elements and their flanking DNA sequences distinct from the human genome, they also do not match the genome of J.C. Venter, J.D. Watson, or any other sequenced model primate. We are currently trying to obtain more genomic information on this elusive primate, which might give us hints to its evolutionary ancestry and its planktonic habitat. A first important observation in that respect is the apparent overabundance of DNA fragments derived from odorant receptors. This enrichment suggests that the micro-primate makes thorough use of its olfactory sense, most likely for finding nutrients and evading predators.
There is little doubt that the bioinformatical discovery of the micro-primate will have as far-reaching consequences as the ant populations living in outer space, which were identified in 1999 through the discovery of dense clumps of formic acid in interstellar molecular clouds.
I have adjusted some numbers and links in the main article. For those interested in further pursuing this line of research, here is a list of the Alu-containing ocean samples. Unfortunately, we don’t have enough time to work on this, as we are already preparing our next scoop: a comprehensive metagenomic analysis of the ALH84001 meteorite.