Ah, the evils of strong drink. Or weak drink. You all know that you shouldn’t drink alcohol to excess during pregnancy, and the reason is that it can affect fetal development. We take zebrafish eggs and put them on a real bender: we soak them in various concentrations of alcohol (which are hard to compare with human blood alcohol levels, I’m afraid, but trust me: these are such gross levels of ethanol that mere humans would be dead and pickled. Fish are tough), and let them stew for hours. Since fish development is much, much faster than human development, it’s rather like having a woman start drinking straight Everclear a few weeks after discovering she’s pregnant, and staying snockered throughout the first trimester.

So don’t try this at home, kids.

The animal on the left is a teetotaler control. The one on the right is going to get washed in 3% alcohol at about 4 hours of development. It’ll be obvious; a label will pop up, and also the eggs are embedded in agar to immobilize them, and the agar will go cloudy and dark for a while as the alcohol soaks in.

Even if you aren’t intimately familiar with fish embryology, you should be able to see that the one on the right develops more slowly. Especially at the end, the one on the left will be twitching vigorously and spinning in the chorion, while the lush on the right is much slower. There are also some subtle deformities in tail shape, and you might notice odd schmutzy gunk on the animal’s epidermis…more about that later.

Also, you’ll notice that we started both recordings immediately after fertilization—I was hovering over the tank, and as soon as momma and daddy squirted out the gametes, I scooped them up and slapped ’em down in a dish, to guarantee that everything was starting precisely in synchrony. These movies start a little earlier and go on a little longer than the previous example.


  1. #1 Ichthyic
    September 28, 2006

    you whine a lot, TJ, but do have the slightest clue what you’re whining about?

    tell us genius, why would a developmental biologist use chemicals to study patterns of development?

    do you REALLY think what PZ was doing was simply trying to see if there was a negative effect of alcohol on development? If so, methinks you have spent too much time drinking yourself.

    you truly are making us all laugh at you, without realizing it, apparently.

  2. #2 Ichthyic
    September 29, 2006

    why do i think that Jason’s mother drank a lot when she was pregnant with him?

  3. #3 Ichthyic
    September 29, 2006

    ” We[‘re]just wash[ing] the embryo with whatever substance we’re interested in testing, and see if and how the cells react”.

    hmm, I’m looking, looking….

    i don’t see where PZ says that’s what he’s doing.

    can you point out where you mined that quote from in the post?

    I really can’t find it.

    you really don’t get it do you?

    the idea of testing chemical concentrations on embryos is to see specifically which aspects of development are affected and how.

    go figure, we actually learn things from that about how development proceeds, and get more clues about mechanisms.

    alcohol isn’t a random choice, duh.

    you might get a clue as to the specifics of what he was looking for at the end of the post, when PZ says:

    There are also some subtle deformities in tail shape, and you might notice odd schmutzy gunk on the animal’s epidermis…more about that later.

    you take a simplified presentation as being evidence of an overly simplistic experiment.

    bad swifty! bad!

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