What do we do all day?

[Picture: NHM]

I thought I should talk a little bit about the kind of work we do at the NHM. The research group I'm in is primarily interested in examining the evolutionary relationships among different lineages and species of beetles using DNA sequences (a pretty daunting feat given that about 25% of all species in the world are beetles) and the evolutionary and ecological forces responsible for beetle diversity. Secondary to all of the beetle work, the lab also works on some similar questions in flies and also the Papilio dardanus project which I work on, looking at the evolutionary biology of Batesian mimicry in this species.

The study of biological relationships (systematics) has been a core part of the museum's work since it's beginning and is intimately tied with the process of assigning names to species and higher groups (the discipline of taxonomy). Ever since Charles Darwin wrote the Origin, biologists have been interested in learning how the diversity of life forms we see today arose. Classically, organisms were grouped on the bases of shared characteristics, such as all mammals having hair and producing milk, with the groups assembled at a higher level using the discretion of the scientist. Such methods persisted for a long time, but were very subjective.

The arrival of computer power made it possible to be much more systematic in approach. Now, the possession of suites of traits could be coded numerically for all the organisms under study and the most parsimonious (simplest) evolutionary tree which would explain the data could be calculated. These methods are very powerful and made it possible to infer the relationships among large numbers of species and, critically, higher-level groups such as genera or families. These methods are still used today, particularly when fossil taxa are being examined - their morphological characters can be coded as for any existing species.

The second revolution in systematics is the use of DNA sequencing. Now, all subjectivity in character coding is removed and the DNA sequences can be analysed to give the evolutionary tree. This is far from straightforward and requires the use of very sophisticated mathematical models of DNA sequence evolution and large amounts of computing power. This technique has been enormously successful and is especially useful when dealing with problematic animals (such as insects) where it can be very difficult to distinguish one species from another on morphology alone and large numbers of species remain undescribed. These are the methods our group uses at the museum for our work.

New advances in technology mean that it is becoming easier and easier to get sequences from more and more genes from more and more species and with increasing computer power, ever more complicated models can be used to infer the most likely evolutionary tree. With a growing number of species having completely sequenced genomes, the next revolution in systematics - phylogenomics - may be just around the corner. This is a very exciting time to be in a molecular systematics lab.