What do we do all day? Part II

If you go to the Natural History Museum and take the Darwin Centre tour, you will pass through part of the now famous cocoon. Part of this looks out into some of the museum's molecular labs, and you can watch scientists (like me) at work. This is the view we get when we look back (at you!) from our labs. But what are we doing in there with robots, labcoats and pipettes? Why does the Natural History Museum have a molecular lab at all?

One of the things I have been working on is using the museum's collections of insects (housed in the lower floors of the cocoon) as a source of DNA for molecular studies into the evolution of mimetic wing patterns in butterflies. I take legs from specimens collected in Africa (some over 90 years old) and preserved in envelopes or pinned in drawers.

I can get all the DNA I need from a single leg, even for these very old specimens.

The butterfly legs are soaked overnight in a special buffer solution along with a proteinase enzyme which helps break down the tissue and allows the DNA to diffuse out but doesn't destroy the specimen. After this, the leg can be dried and returned to the specimen and the liquid can be purified to extract the DNA:

This is the filter I use to purify the DNA. When liquid is passed through, the white filter layer binds DNA whilst the rest of the buffer comes through the bottom. After washing, I can wash the DNA out of the filter with an elution buffer and I have clean DNA from a 90 year old dried butterfly. This DNA can then be used in a PCR reaction to selectively amplify the genes I am interested in:

A PCR machine

PCR product imaged using a dye which binds DNA and makes it visible under UV light

The PCR product can be sequenced (you probably didn't know that the museum has its own in-house DNA sequencing facility).

I can now use this in my analyses, just as I would do with DNA sequences from fresh specimens. Such work is only possible at the museum because of the priceless collections and the facilities in the state-of-the-art Darwin Centre. I hope that if you come to the Natural History Museum, you do take the time to go on the Dawin Centre cocoon tour and learn more about the cutting-edge research taking place there.