Digital Biology Fridays

Let's play anomaly! Most of this week, I've written about the fun time I had playing around with NCBI's Blink database and finding evidence that at least one mosquito, Aedes aegypti, seems to have been infected at some point with a plant paramyxovirus and that the paramyxovirus left one of its genes behind, stuck in the mosquito genome. During this process, I realized that the method I used works with other viruses, too. I tried it with a few random viruses and sure enough, I found some interesting things. You've got a week to give it a try. Let's see ... Read more

Here's a fun puzzler for you to figure out. The blast graph is here: The table with scores is here, click the table to see a bigger image: ... Read more

If you look below the fold, you can see two molecules locked in a tight embrace. These molecules or their closely related cousins can be found in any cell because their ability to evolve is slowed by their need to interact with each other in the right way. In an earlier post, I asked: Who are they? One partner is a small bit of ... Read more

Last week I posted an image with two molecules (below the fold), one protein and one nucleic acid, and asked you about the probability of finding similar molecules in different species. You gave me some interesting answers. DAG made me clarify my question by asking what I meant by "similarity." I was wondering whether I would be likely to find a statistically relevant match by doing a BLAST search and I hadn't really thought about the cutoff values. I decided to guess and say that that the protein would be about 30% similar and the nucleic acid about 60 ... Read more

This is a fun puzzle. The pink molecule is a protein and the other molecule is a nucleic acid. If I gave you the amino acid sequence of this protein, or the nucleotide sequence of this nucleic acid, what is the probability of finding a similar sequence in a different species (picked at random)? A. High B. Medium C. Low D. It ... Read more

As many of you know, I'm a big fan of do-it-yourself biology. Digital biology, the field that I write about, is particularly well-suited to this kind of fun and exploration. Last week, I wrote some instructions for making a phylogenetic tree from mitochondrial genomes. This week, we'll continue our analysis. I wrote this activity, in part, because of this awful handout that my oldest daughter brought home last year. She presented me with an overly photocopied paper that showed ... Read more

Last year I wrote about an experiment where I compared a human mitochondrial DNA sequence to primate sequences in the GenBank. Since I wanted to know about the differences between humans, gorillas, and chimps, I used the Entrez query 'Great Apes' to limit my search to a set of sequences in the PopSet database that contained gorillas, bonobos, chimps, and human DNA. A week ago, I tried to repeat this experiment and...

It didn't work.

All I saw were human ... Read more

During the past few Fridays (or least here and here), we've been looking at a paper that was published from China with some Β-lactamase sequences that were supposedly from Streptococcus pneumoniae. The amazing thing about these particular sequences is that Β-lactamase has never been seen in S. pneumoniae before, making this a rather significant (and possibly scary) discovery ... Read more

I began this series last week with a question about a DNA sequence that was published and reported to be one the first beta-lactamases to be found in Streptococcus pneumoniae. Mike has a great post about one of problems with this paper. I think the data themselves are awfully suspicious. So, last week I suggested that you, dear readers, go and find out why. I gave you a ... Read more

Last Friday, we had another in the series of weird DNA structures. (You can see the first here). I asked the audience to identify the unusual feature in this molecule. Here's the first picture:

tags:

Here's the answer: ... Read more