Ask Dr. Science

Shotgun sequencing. Sounds like fun. Speculations on the origin of the phrase I think that this term came from shotgun cloning. In the early days of gene cloning before cDNA, PCR, or electroporation; molecular biologists would break genomic DNA up into lots of smaller pieces, package DNA in lambda phage, transduce E. coli, and hope for the best. Consistent with the shotgun metaphor, we even used to store our microfuge tubes in plastic bullet boxes that my boss found at the sporting goods store. (Apparently this practice was unique ... Read more

Considering that several genomes that have been sequenced in the past decade, it seems amazing in retrospect, that the first complete bacterial genome sequence was only published 12 years ago (1). Now, the Genome database at the NCBI lists 450 complete microbial genomes (procaryotes and archea), 1476 genomes from eucaryotes, 2145 viruses, and genome sequences from ... Read more
About a week ago, I offered to answer questions about subjects that I've either worked with, studied or taught. I haven't had many questions yet, but I can certainly answer the ones I've had so far. Today, I'll answer the first question: How do you sequence a genome? Before we get into the technical details, there are some other genomic questions that you might like answered. How much does it cost to sequence a genome? I remember in 2002, when we were at the ... Read more
In the effort to help us define a few basic concepts, PZ started out by giving us a nice simple definition of a gene, but as he, rightly noted:
I tell you right now that if I asked a half dozen different biologists to help me out with this, they'd rip into it and add a thousand qualifiers, and it would never get done.
Well, okay, technically speaking he didn't ask me for help. But, since I'm a ... Read more
Are there scientific terms or concepts that you'd like to know more about? Looking for a bit more of an explanation? Confused about the difference between DNA and RNA? Some of my fellow SciBlings, Tara, Chad, John, Janet, and ... Read more

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