Coding is better when done together. Photo by hackNY.
Over at the Molecular Ecologist, Kim Gilbert announces a new initiative, the Molecular Ecologist code snippet repository. It’ll be a place to put bits of useful code that wouldn’t warrant their own publication as a package or program, but would still be helpful to other biologists:
Do you have a script you regularly run to convert between data formats? A quick and easy way to run a certain analysis? Making a common figure for a given type of data? If you’re willing to share your code, we’ll put it online for public access with credit to your name.
To find out how to submit your snippets, go read the whole thing.◼
Over at the Molecular Ecologist, guest contributor Arianne Albert walks through how to make heatmap figures in R.
Heatmaps are incredibly useful for the visual display of microarray data or data from high-trhoughput sequencing studies such as microbiome analysis. Basically, they are false colour images where cells in the matrix with high relative values are coloured differently from those with low relative values. Heatmaps can range from very simple blocks of colour with lists along 2 sides, or they can include information about hierarchical clustering, and/or values of other covariates of interest. Fortunately, R provides lots of options for constructing and annotating heatmaps.
I’ve personally used heatmap graphics for visualizing population structure in a sample, or linkage disequilibrium along a stretch of genetic sequence, but I haven’t done anything very complex. Arianne’s examples use a data set that’s freely available on Dryad, and she includes a lot of step-by-step detail to build up complex figures—if you’re going to be visualizing some microarrary results or metagenomics data any time soon, you should read the whole thing, and probably bookmark it.◼
This week at the Molecular Ecologist, I’m discussing a new study from the blog’s parent publication, Molecular Ecology, which traces the origins of gene variants in a wild population of Soay sheep … back to domestic sheep.
The Soay sheep haven’t been completely isolated from other breeds. In recent centuries, they shared the Saint Kilda islands with humans, who kept domesticated sheep—providing several hundred years of opportunity for what geneticists call “an admixture event,” and everyone else calls “sex,” between the Soay breed and those domesticated sheep.
To learn how the study’s authors pinpointed the origin of the domestic genes variants, and how those variants have fared in the wild sheep, go read the whole thing.◼
This week at The Molecular Ecologist, Mark Christie shares some tips for how to take care of that massive genetic dataset that’s just come off the high-throughput sequencer:
Congratulations! You have recently received a file path to retrieve your hard-earned next-generation sequencing data. You quickly transfer the files to the computing cluster you work on or perhaps, if you only have a few lanes of data, to your own computer. But before you begin messing around with your data, you quickly realize that you should come up with a plan to back up and store unadulterated versions of your files.
For a nice set of recommendations with some step-by-step instructions, go read the whole thing.◼