sequence analysis

A few weeks back, we published a review about the development and role of the human reference genome. A key point of the reference genome is that it is not a single sequence. Instead it is an assembly of consensus sequences that are designed to deal with variation in the human population and uncertainty in the data. The reference is a map and like a geographical maps evolves though increased understanding over time.

From the Wiley On Line site: ... Read more

In our series on why $1000 genomes cost $2000, I raised the issue that the $1000 genome is a value based on simplistic calculations that do not account for the costs of confirming the results. Next, I discussed how errors are a natural occurrence of the many processing steps required to sequence DNA and why ... Read more

I had the good fortune on Thursday to hear a fascinating talk on deep transcriptome analysis by Chris Mason, Assistant Professor, at the Institute for Computational Biomedicine at Cornell University. 

Several intriguing observations were presented during the talk.  I'll present the key points first and then discuss the data.

These data concern the human transcriptome, and at least some of the results are supported by  follow on studies with data from the pigmy tailed macaque.

Some of the most interesting points from Mason's talk were:

  1. A large
  2. ... Read more
These days, DNA sequencing happens in one of three ways. In the early days of DNA sequencing (like the 80's), labs prepared their own samples, sequenced those samples, and analyzed their results. Some labs still do this. Then, in the 90's, genome centers came along. Genome centers are like giant factories that manufacture sequence data. They have buildings, dedicated staff, and professional bioinformaticians who write programs and work with other factory members to get the data entered, analyzed, and shipped out to the databases. (You can ... Read more

You might think the coolest thing about the Next Generation DNA Sequencing technologies is that we can use them to sequence long-dead mammoths, entire populations of microbes, or bits of bone from Neanderthals.


... Read more

Last spring, I gave my first hands-on workshop in working with Next Generation Sequencing data at the Eighth Annual UT-ORNL-KBRIN Bioinformatics Summit at Fall Creek Falls State Park in Tennessee. The proceedings from that conference are now on-line at BMC Bioinformatics and it's fun to look back and reflect on all that I learned at the conference and all that's happened since.


... Read more

No more delays! BLAST away!

Time to blast. Let's see what it means for sequences to be similar. 

First, we'll plan our experiment.  When I think about digital biology experiments, I organize the steps in the following way: 

           A.  Defining the question

B.  Making the data sets

           C.  Analyzing the data sets

D.  Interpreting the results

I'm going intersperse my results with a few instructions so ... Read more

We'll have a blast, I promise! But there's one little thing we need to discuss first...

I want to explain why I'm going to use nucleotide sequences for the blast search. (I used protein the other day). It's not just because someone told me too, there is a solid rational reason for this.

The reason is the redundancy in the genetic code.

Okay, that probably didn't make any sense to those of you who didn't already know the answer. Here it is. ... Read more

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

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