Bioinformatics

I know some of you enjoy looking at data and seeing if you can figure out what's going on. For this Friday's puzzler, I'm going to send you to FinchTalk, our company blog, to take a look at lots of data from a resequencing experiment that was done to look for SNPs and count alleles. The graph is at the end of the post. The graph shows data from 4608 reads (sequenced from both strands, forward and reverse). And there are some interesting patterns. Can you figure them out? Read more
Goodbye desktop, we're off to see the web. Both my students and I have been challenged this semester by the diversity of computer platforms, software versions, and unexpected bugs. Naturally, I turned to the world and my readers for help and suggestions. Some readers have suggested we could solve everything by using Linux. Others have ... Read more
Is it real or is it April Fools? The March 21st issue of Science has an interesting news article by Elizabeth Pennisi and a letter to the editor about a proposal to wikify GenBank. Currently, the NCBI holds the original authors responsible for editing or correcting entries and this does cause problems when those authors fail to return to the scene and fix what they've submitted. Some researchers are suggesting that third parties be allowed to fix some of those mistakes or at least add comments to records, to warn the unwary. There are some good arguments on both sides and it' ... Read more
I made this video (below the fold) to illustrate the steps involved in making a phylogenetic tree. The basic steps are to:
  1. Build a data set
  2. Align the sequences
  3. Make a tree
In the class that I'm teaching, we're making these trees in order to compare sequences from our metagenomics experiment with the multiple copies of 16S ribosomal RNA (rRNA) genes that we can find in single bacterial genomes. Bacteria contain between 2 to 13 copies of 16S rRNA genes and we' ... Read more
Have you ever wondered how to view and annotate molecular structures? At least digital versions? It's surprisingly easy and lots of fun. Here's a movie I made that demonstrates how you can use Cn3D, a free structure-viewing program from the NCBI. Luckily, Cn3D behaves almost the same way on both Windows and Mac OS X. ... Read more
One of my colleagues has a two part series on FinchTalk (starting today) that discusses uncertainty in measurement and what that uncertainty means for the present and Next Generation DNA sequencing technologies. I've been running into this uncertainty myself lately. I have always known that DNA sequencing errors occur. This is why people build tools for measuring the error rate and why quality measurements are so useful for determining which data to use and which data to ... Read more
I think all of us; me, the students the OO advocates, a thoughtful group of commenters, some instructors; I think many of us learned some things that we didn't anticipate the other day and got some interesting glimpses into the ways that other people view and interact with their computers. Some of the people who participated in the challenge found out that it was harder than they expected. Lessons learned Okay, what did we learn? 1. The community is the ... Read more
It's a Solexa data directory. I've held off on blogging about Next Generation Sequencing here, but now that one of my colleagues has started blogging about it, it seems like a good time to write a little about FinchTalk, our company blog. We've decided that we can serve an educational role for people who are interested in Next Generation DNA Sequencing. Certainly, FinchTalk is our company blog and it is a place where you can expect to read about our products. But, we've noticed that quite often, the sexy technologies and ... Read more
Okay OpenOffice fans, show me what you can do. Earlier this week, I wrote about my challenges with a bug in Microsoft Excel that only appears on Windows computers. Since I use a Mac, I didn't know about the bug when I wrote the assignment and I only found out about it after all but one of my students turned in assignment results with nonsensical pie graphs. So, I asked what other instructors do with software that behaves differently on different computing platforms. I never did hear from ... Read more
I read about this in Bio-IT World and had to go check it out. It's called the Genome Projector and it has to be the coolest genome browser I've ever seen. They have 320 bacterial genomes to play with. Naturally, I chose our friend E. coli. The little red pins in the picture below mark the positions of ribosomal RNA genes (It's not perfect, at least one of these genes is a ribosomal RNA methyltransferase and not a 16S ribosomal RNA.) ... Read more

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