When purified, it glows with an unearthly light. You can't go "chemical free" and try to escape it. It's part of our bones and it forms the backbone of our DNA. A tool for good, a tool of war, essential for gardening, and infamous as a pesticide; phosphorus is truly an amazing element. Amazing too, are the stories about it's discovery and our history with using it. Many of the stories in ... Read more
Metagenomics is a field where people interrogate the living world by isolating and sequencing nucleic acids. Since all living things have DNA, and viruses have either DNA or RNA, we can identify who's around by looking at bits of their genome.
Researchers are using this approach to find the culprit that's killing the honeybees. We're also trying to find out who else shares our bodies, and lives in our skin, in our stomachs, and other places where the sun doesn't shine. Craig Venter used ... Read more
The simple fact is this: some DNA sequences are more believable than others.
The problem is, that many students and researchers never see any of the metrics that we use for evaluating whether a sequence is "good" and whether a sequence is "bad."
All they see are the base calls and sequences: ATAGATAGACGAGTAG, without any supporting information to help them evaluate if the sequence is correct. If DNA sequencing and personalized genetic testing are to become commonplace, the practice of ignoring data quality is (in my opinion) simply unacceptable.
So, for awhile anyway, I'm ... Read more
We have lots of DNA samples from bacteria that were isolated from dirt. Now it's time to our own metagenomics project and figure out what they are. Our class project is on a much smaller scale than the honeybee metagenomics project that I wrote about yesterday, but we're using many of the same principles.
The general process is this:
1. We sort the chromatogram data to identify good data and separate it from bad data. Informatics can help you determine if data is
The next time you bite into a crisp juicy apple and the tart juices spill out around your tongue, remember the honeybee. Our fall harvest depends heavily on honeybees carrying pollen from plant to plant. Luscious fruits and vegetables wouldn't grace our table, were it not for the honeybees and other pollinators.
Lately though, the buzz about our furry little helpers hasn't been good. ... Read more
Would you like to have some fun playing with chromatograms and helping our class identify bacteria in the dirt?
This quarter, my bioinformatics class, at Shoreline Community College, will be working with chromatograms that were obtained by students at Johns Hopkins University, and graciously made available by Dr. Rebecca Pearlman. (See see "Sequencing the campus at the Johns Hopkins University" for more background.)
We are going to do a bit of metagenomics by using FinchTV and ... 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
One time I was watching a football game on TV and they had a short quiz, called "You make the call" or something like that, and you had to watch a play and pretend to be a referee. A short video clip showed football players falling over each other. Then you were three possible calls that a refereee might make and asked to chose which was correct. After the commercial, the announcer would tell you which choice was right and explain why it was correct. I suppose this was a trick to make us watch the commercials, but I thought the game was kind of fun.
My SciBling "Mike the Mad" had a great ... Read more