Slashdot Mirror

← Back to Stories (view on slashdot.org)

Biology's McGyver: DIY DNA P.C.R.

Posted by michael on from the cheaper-is-better dept.

joesao writes "In this short, charming interview, Dr. Eva Harris talks about popularizing biology by doing what she calls "knowledge-based" technology transfer: "...people purify DNA for P.C.R. processing with a fancy substance made of silica particles, which costs about $100 for a few milliliters. [...] So what we've done is buy a 20-pound bag of ceramic dust for $5 at the hobby store. And you wash the stuff in nitric acid and sterilize it, and then you have thousands of tubes of that substance. We're not violating anything because the commercial manufacturers have their way of doing this, and we have ours." Open-source biology, anyone?"

4 of 55 comments (clear)

  1. What I want... by TitaniumFox · · Score: 4, Funny

    Is a DYI thermocycler. Programmable. With a heated top.

    Additionally, you can snag the silica gel needed for PCR purification from Vacutainers used to collect and subsequently separate blood.

    --
    -- I'd say your post was about 3 monkeys, 18 minutes.
    1. Re:What I want... by mcdrewski42 · · Score: 3, Funny

      How do I moderate this as (+1 Huh?)

      --
      /* affect != effect */ void affect(int *thing,int effect) { *thing += effect; }
  2. Rather hyperbolic by Otter · · Score: 4, Insightful
    I'm sure this work is very valuable, but either she or the reporter (or both) make her come across as far, far more revolutionary than she is.

    For instance, people purify DNA for P.C.R. processing with a fancy substance made of silica particles, which costs about $100 for a few milliliters.

    I incubate a piece of tissue with a couple of cents worth of buffer and proteinase, and then dilute the resulting glop in water. Obviously different protocols call for different methods, but routine clinical preps shouldn't call for anything nearly as elaborate as what she describes. Anyone know what this silica thing she's talking about is? Qiagen spin preps?

    This is called manual cycling. Suddenly, you don't need that $10,000 machine. Now, I didn't discover manual cycling or P.C.R., but I've helped popularize it.

    Uh, no kidding you didn't invent manual cycling. That's how everybody did PCR until the cyclers became available.

    Like I said, I can easily see where it's a very valuable activity to generate manuals and reagent sources for cheap techniques, but the interview makes her sound vastly more inventive than she is.

    --
    What I'm listening to now on Pandora...
    1. Re:Rather hyperbolic by Anonymous Coward · · Score: 3, Informative

      Almost every company that sells you some sort of PCR purification / gel purification / miniprep kit that has a spin column or a vac manifold column has some "proprietary formulation" in their columns, but it's silica based. Decrease the pH to about 3.5-4 and your DNA sticks via its phosphodiester backbone. Change it back to 7-8, and the DNA elutes into your TE/H2O/whatever. This is exactly what she is talking about. There were 2 papers published around '83-'84 that describe the use of silica gel for DNA purification. Finding some modification that makes your yield go up and slapping a sticker on it and selling it is big money.

      Kids. Back in the day, we'd make our own competant E. coli using the Hanahan method.

      In the walk-in -20C.
      Uphill.
      Both ways.