DNA

Organisms with linear chromosomes have to solve the problem that DNA replication makes them shorter. This is due to the fact that DNA polymerase can only add bases to the terminal 3'-OH of a DNA chain. The DNA replication initiation complex uses RNA primers to provide the initial 3'-OH and ... Read more

Today (4/25) is national DNA day.  Digital World Biology™ is celebrating by sharing some of our favorite structures of DNA. We created these photos with Molecule World™ a new iPad app for viewing molecular structures. As we are taught in school, the double stranded DNA molecule is a right-handed helix as determined by Watson and Crick using Franklin's x-ray diffraction images [1]. This B- ... Read more

Some people, like Imelda Marcos and Dr. Isis have a thing for fancy shoes. I go crazy for gadgets.

For my birthday this year, my family bought me a new iPhone! Yeah! So, I've been killing several hours today filling it with cute little iPhone apps. Who knew one little phone could be so much fun? One app, I enjoy, is called Molecules. Molecules lets you download structure files from the Protein Data Bank (PDB) and play with the structures on your phone!

I got my copy of "A short guide to the human genome" by Stewart Scherer today from Cold Spring Harbor Laboratory Press (2008, ISBN 978-087969791-4). Usually, I would wait until after I've read a book to write a review, but this book doesn't require that kind of study. As soon I skimmed through it and read some of the questions and answers, I knew this would be the kind of quick reference that I would like to have sitting above my desk. Scherer has compiled a wonderful text that not only answers many of the kinds of questions that I can think to ask about the human ... Read more

Believe it or not, this is a DNA kiss. Have a loverly Valentine's DNA! (And just in case you're wondering, yes, I did put it on a coffee mug.)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

One of my readers asked: Why does genome sequencing cost so much? My short answer is because it's big. But I thought it would be fun to give a better answer to this question, especially since I'm sure many of you are wondering the same thing. Okay, so let's do some math. Don't worry, this math isn't very complicated and I'll explain where most of the numbers come from. Estimating costs from salaries First, we'll take the easy route. My experience with grant budgets has taught me that the greatest cost for any project comes from salaries. If ... Read more

If you've read any of the many stories lately about Craig Venter or Jim Watson's genome, you've probably seen a "SNP" appear somewhere. You may be wondering, and rightly so: just what is a SNP?

Never fear, hopefully this post will answer some of those questions.

SNP stands for Single Nucleotide Polymorphism. That's a mouthful. It means some people, will have one base at a certain position, in a sequence of bases, and other people will have a different base at that position. The two forms of SNP are called "alleles." (Usually there are two forms, but that's ... Read more