How to make a (real) butterfly out of paper

The instructions for making an origami butterfly could be sketched on the back of the page it was folded out of, but how long are the instructions for making a real butterfly?

The life recipe of a butterfly, the DNA sequence of its genome, is about 280 million "base pairs" long. The art of origami might offer a means to put this number into perspective. Cambridge scientist Alex Bateman has developed an origami model of the DNA "double-helix". So now, rather than making a paper butterfly, we can try to figure out how much paper we'd need to create the complete DNA sequence of a real one.

In a recent record-breaking feat, Dr Bateman lead the construction of a 247 metre long paper DNA strand. This model represented about 10,000 base pairs, only a tiny fraction of a genome. A complete butterfly genome made in this way would require 25 million sheets of paper and would easily stretch across the Atlantic. The human genome, which is more than ten times the size, would wrap around the world three times!

Of course this is a huge-scale model, and in reality the human genome, stretched out in one long line, would be a few metres in length. Also, the genome is not a single DNA strand - it is divided up into 23 chromosomes (21 in a butterfly). Still, it is remarkable that all of this DNA (in fact two copies of each chromosome - one from each of our parents) is crammed into every single living cell in our bodies.

Mendeley

To organise my collection of papers and references I use the reference manager Mendeley.

Mendeley is a desktop application (very similar to Mekentosj Papers in this respect), a cloud-based community for backup, storage and sharing of papers and a scientific social network (a bit facebook, a bit LinkedIn).

The desktop application curates your collection of pdfs:

The panel on the top left contains your list of folders and public groups (see below for more on these), the bottom left panel enables you to search by author, author's keywords, journal or personal tags in your tag-cloud. The middle panel displays the documents in whatever folde is open and the right panel shows the metadata for the selected paper (title, author, tags, abstract etc.). Clicking on the pdf symbol next to a reference opens the reading screen:

Here you have the option to read fullscreen, as well as edit metadata on the right as well as highlight and annotate the paper itself (very handy!). Mendeley tabs all the references you may have open at any one time, making it simple to flip between them.

Importing papers is simple. You can either drag a pdf into your libary or select the 'Add Documents' button in the library screen. Mendeley then adds the pdf to your library, checks for metadata and automatically fills out Title, author, publication etc. This isn't perfect but it nearly always works and is improving - it's simple enough to edit incorrect entries: Mendeley lets you search Google Scholar with the title to fill out these fields if it can't find the reference in its catalogue. Best of all, Mendeley copies the pdf into a folder in its area of your hardrive and renames it in a format of your choosing: 'j.1365-294X.2011.05127.pdf' now becomes 'Legrand et al 2011 Molecular Ecology.pdf' for instance. These are stored in nested folders with a structure of your choosing.

This is all fantastic, and the cross-platform nature (there are Windows, OS X and Linux versions of Mendeley Desktop as well as iPhone and iPad apps to read your papers on the move) beats all competition hands-down, but Mendeley really comes into its own with its use of the cloud. Firstly, Mendeley allows you to sync your files between multiple computers - just click 'Sync' in the desktop app and all your references are downloaded. Amazing - no more carting around an external hard drive full of pdfs so you can work at home.

Mendeley is also great for collaboration: you can search for other users by email address and add your colleagues. You can then make groups or shared folders of references (complete with a facebook-like wall for discussion) with your collaborators. I use this feature to help run our journal club - it works brilliantly!

Finally, you can make a public profile to go with your Mendeley web presence:

Neat. This will make it easier for my colleagues to find me and share references.

Mendeley also does citation management. You can either export folders as Bibtex lists, copy and paste individual citations from the software itself, or install the plugin for Microsoft Word or Open Office. This lasst option is so easy to use its unreal. In Word:

Alt+M brings up a dialogue box where you can search your library

Select the appropriate reference and it is added. When you've finished the document, use the insert bibliography option in Word:

Very cool. The reference style is customizable too. 

Thinking about Acraea again today

Female Acraea jodutta

Keep thinking about Acraea species. They're Mullerian mimics from Africa, and often the models for Papilio dardanus. Some are sympatrically polymorphic, some sexually dimorphic and some are infected by Wolbachia male-killers.

"The most interesting butterfly in the world"

Female Papilio dardanus, form hippocoonides