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Hi, my name's Jang Singer, and that's not even the way to say it is it?
I can't even say my own name!
Hi, my name's Jan Singer and I'm going to be showing you tetrad dissection using budding yeast.
I have done three digestions, one at 10, one at 15 and one at 20 minutes, and I have chosen the last.
I've inoculated my plate, and I've just placed it on the stage.
The first thing I'm going to do is mark the plate, just where the lever is
so that I have a position to put it back in roughly.
I'm in the inoculum at the moment, but before I start I'm just going to move to the side to clean the needle.
There.
The agar is sterile,
and anything that's on there will come off.
Now what I'm looking for are four spores, in a diamond-shape or cruciform-shape.
Now I can see one there that I think is quite nice,
and I've picked up the tetrad and I'm going to take it to position A1 within the matrix.
I'm just going to bring the needle back up to the surface,
just like that.
They've broken apart nicely.
Place this at position B1.
And separate.
There we go, there it is.
Try to pick up two, seeing as they want to stay together.
Now picking up is a fairly fast movement, a fast movement picks them up,
a slow movement, or agitation of the needle will place them.
Pick up that last spore,
take it to the final position, place it there, that's it.
Now I go back up and check make sure they're not bubbles in the surface of the agar,
and I'm quite sure that they're not.
Now I take this spore just to one side a second,
whilst I make...
...a mark in the centre of the agar,
so that I can find position A1 if I have to remove the plate.
And that will be seen even if it is out of focus,
you can see that there's a shadowy mark there.
Now I go back to the inoculum,
to find another tetrad.
It goes back exactly in the same position so had I picked up three spores,
I would have been able to pick up...
...the final spore which would have been here.
And that's it!
Thank you.