Bioinformatics

We had a great discussion in the comments yesterday after I published my NJ trees from some of the flu sequences. If I list all the wonderful pieces of advice that readers shared, I wouldn't have any time to do the searches, but there are a few that I want to mention before getting down to work and posting my BLAST results. Here were some of the great suggestions and pieces of advice; 1. Do a BLAST search. Right! I can't believe I didn't do that first thing, I think the ... Read more

What tells us that this new form of H1N1 is swine flu and not regular old human flu or avian flu?

If we had a lab, we might use antibodies, but when you're a digital biologist, you use a computer.

Activity 4. Picking influenza sequences and comparing them with phylogenetic trees

We can get the genome sequences, piece by piece, as I described in earlier, but the NCBI has other tools that are useful, too.

The Influenza Virus Resource will let us pick sequences, align them, and make trees so we can quickly compare the sequences to ... Read more

This afternoon, I was working on educational activities and suddenly realized that the H1N1 strain that caused the California outbreak might be the same strain that caused an outbreak in 2007 at an Ohio country fair. UPDATE: I'm not so certain anymore that the strains are the same. I'm doing some work with nucleic acid sequences to look further at similarity. Here's the data. Once I realized that the genome sequences from the H1N1 swine flu were in the NCBI's virus genome resources database, I had to take a look. And, like eating potato chips, making ... Read more

I was pretty impressed to find the swine flu genome sequences, from the cases in California and Texas, already for viewing at the NCBI. You can get them and work them, too. It's pretty easy. Tomorrow, we'll align sequences and make trees. Activity 3: Getting the swine flu sequence data 1. Go to the NCBI, find the Influenza Virus Resource page and follow the link to: 04/27/2009: Newest swine influenza A (H1N1) sequences. 2. You'll see a page that looks like this: ... Read more

I'm a big of learning from data. There are many things we can learn about swine flu and other kinds of flu by using public databases. In digital biology activity 1, we learned about the kinds of creatures that can get flu. Personally, I'm a little skeptical about the blowfly, but... Now, you might wonder, what kinds of flu do these different creatures get? Are they all getting H1N1, or do they get different variations? What are H and N anyway? We can discuss all of these, but for now, lets see what kinds of flu strains infect different kinds of creatures. Activity 2. What ... Read more

Genome sequences from California and Texas isolates of the H1N1 swine flu are already available for exploration at the NCBI. Let's do a bit of digital biology and see what we can learn. Activity 1. What kinds of animals get the flu? For the past few years we've been worrying about avian (bird). Now, we're hearing about swine (pig) flu. All of this news might you wonder just who gets the flu besides pigs, birds, and humans. We can find out by looking at the data. Over the past few years, researchers have been sequencing influenza genomes and depositing ... Read more

A couple of years ago, I answered a reader's question about the cost of genome sequencing. One of my readers had asked why the cost of sequencing a human genome was so high. At that time, I used some of the prices advertised by core labs on the web and the reported coverage to estimate the cost of sequencing Craig Venter's genome. As you can imagine, the cost of sequencing has dropped quite a bit since then.

In 2007, Genome Technology reported the cost of sequencing ... Read more

In which we identify unknown human proteins.

Yesterday, I wrote about using the BLOSUM 62 matrix to calculate a score for matches between two proteins. Those scores give us a good start on understanding how blastp determines whether two sequences are matching by chance or because they're more likely to be related. But that's not all there is to calculating a blast score, and there's at least one other statistic to consider as well, the E value.

It all ... Read more

In which we search for Elvis, using blastp, and find out how old we would have to be to see Elvis in a Las Vegas club.

Introduction
Once you're acquainted with proteins, amino acids, and the kinds of bonds that hold proteins together, we can talk about using this information to evaluate the similarity between protein sequences. We can easily imagine that if two protein sequences are identical, then those proteins would have the same kind of activity. But what about proteins that are similar in some regions, and not others, or proteins that only ... Read more

"Digital biology," as I use the phrase, refers to the idea of using digital information for doing biology. This digital information comes from multiple sources such as DNA sequences, protein sequences, DNA hybridization, molecular structures, analytical chemistry, biomarkers, images, GIS, and more. We obtain this information either from experiments or from a wide variety of databases and we work with this information using several kinds of bioinformatics tools.

The reason I'm calling this field "digital biology" and not "bioinformatics" (even though I typically use the terms ... Read more