The world's first camelid cDNA library

When some scholar desperate for a PhD topic turns his gaze to the history of research on camels, October 25, 2008 will undoubtedly mark a new chapter in his exceedingly tedious and irrelevant dissertation. After a year of research, the Camel Health Unit successfully synthesized the first camel-related cDNA.

DNA, being the stuff of heredity, is safely ensconced inside the cell nucleus. While this isolation ensures its integrity, it also makes DNA kind of useless. In order to get something done, the cell must transcribe instructions (genes) from DNA into RNA, which then passes out of the nucleus to be translated into proteins. These proteins are what actually do things in the cell. So if you want to study how genes get expressed rather than just how they get passed on, RNA is of far more interest, because it reflects exactly which instructions are being carried out when. But DNA is easier to study, so we collect the active RNA, copy it back into DNA, and call it cDNA.

Once you have cDNA, you can do all sorts of cool and godlike things. We're looking at the parasite Haemonchus contortus, a worm living in the camel digestive tract that feeds by digesting hemoglobin. We isolated the H. contortus RNA that codes for the protein responsible for digestion and copied it back into cDNA. Next, we'll insert that cDNA gene into the genome of a small bacteria (called a vector) and see if the genetically modified bacteria can digest hemoglobin. We'll then use that bacteria to design a simple diagnostic that would detect the presence of the hemoglobin-digesting protein in camel blood.

An interesting sidenote: even this advanced work has at its root the same large-level changes I've seen throughout Rajasthan. Desertification and overpopulation have led to a reduction in the quality topfeed (trees, tall shrubs) that camels prefer, forcing them to compete with sheep, goats, and cows for low-level grazing. This means that H. contortus, usually only found in sheep here, has moved to camels as the animals are exposed to feces-covered groundfeed.