What Is "Deep Sequencing"?

And how is it different than genome sequencing?

So recently, I've been hearing people outside of the field of genomics refer to "deep sequencing." I'm not sure what that phrase means: I would like to think that, in a philosophical sense, all of the sequencing we do is "deep" (dude). We certainly don't set out to do shallow, stupid, and superficial projects.

If deep sequencing means the depth of coverage--the number of times, on average, a nucleotide is sequenced--depending on the project's goals, the size of the genome, and so on, sometimes we sequence deeply, sometimes we don't.

This sounds like a phrase invented by someone who really doesn't know what he is talking about.

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Lately there have been a lot of projects to sequence a lot of genomes with low coverage (<5X) instead of one genome with high coverage (>25X), so it's become necessary to differentiate between the two approaches.

By Epistaxis (not verified) on 11 Mar 2010 #permalink

Dude, Indeed. I agree, if you're gonna do 'deep' sequencing, better to report on your fold coverage rather than just say 'deep'. Better yet, just say how much coverage you've got, period, regardless of the depth. Now that would be deep.

By Anonymous (not verified) on 11 Mar 2010 #permalink

Mike,

We've been calling 7x assembly for verterbrate genomes "deep sequencing" for years. I have no idea what it means for new sequencing tech, but it will probably come to mean "sequencing that gives us coverage similar to Sanger 7x."

Then again, I don't really know what I'm talking about.

Deep refers to coverage that you can't quite *fathom*. heh heh.

By noddin0ff (not verified) on 12 Mar 2010 #permalink

Deep sequencing is when you sequence many samples of certain genomic region from different individuals to determine low-frequency mutations. You need deep coverage for these, naturally.

Deep Sequencing is a new tool being used to identify the amount of RNA transcripts in specific tissues. It has contributed to a slew of new papers in the miRNA field including a recent paper in RNA by nobel prize winner Andy Fire.

By Doc Wilson (not verified) on 30 Jul 2010 #permalink

Deep sequencing as I've heard it repeated refers to greater coverage to identify rarer variants rather than looking at sequence data that gives you the consensus of a large DNA sample.

Maybe since you're in the genomics field you don't identify this as a difference, but most people who want sequences just want the consensus of some miniprep or PCR. When people use sequence to identify individual variants in a population, they refer to it as deep sequencing. This is just my experience, but other posters seem to agree.

By Erol Bakkalbasi (not verified) on 27 Oct 2010 #permalink

This use of "deep" goes back at least as far as Tolkien (The Lord of the Rings) and Lewis Carroll (Narnia). It was a "deeper" level of magic that let Gandalph and Aslan respectively survive after death, with clear religious connotations. Deep sequencing equally adds a mythical and undefined level of superlative to Brute force and highly error prone sequencing techniques. It goes with massively parallel, avoids being quantitative, and looks impressive in adverts.

By Hugh Fletcher (not verified) on 22 Feb 2011 #permalink

If you don't know about something, it's better not to open your mouth about it!

"This sounds like a phrase invented by someone who really doesn't know what he is talking about."

Seems like its you who has no clue about what you are talking about. You assume something and then ridicule it based upon your assumptions. Get the fact first then start commenting about it, Jeez!