Robert Martienssen - Working with Barbara McClintock

I was trying to do an experiment in which I was trying to link a transposable element to a translocation, a translocation between two different chromosomes in maize. The idea was to get the transposon to hop from one translocated chromosome to another-a pretty simple experiment-but in order to do that I had to be able to identify the plants that had this translocation. It turns out that this translocation was the one that she had done all of her work with in the 1930s, so she was extremely familiar with it. And I asked her if she could help detect these translocated chromosomes. And that involved going to the greenhouse, cutting open the plants with a razor blade, which is a technique that she'd developed, pulling out the male sporocytes, or the male organs that then you could get the sporocytes from, and preparing them for the microscope. And so she actually helped me do that, and it was an extraordinary experience. Even at that age-she was almost 90 years old at that point-she was able to open a maize plant and remove just a few branches from the tassel, then close the maize plant up again, and literally bandage it up as if she was performing an operation, and have it grow normally again, so that you could use the plants for genetics and do the crosses that you needed to do in addition to getting this material. I think before then people had just tended to hack the whole thing out and lose the plant while getting the cytology. So this was a very important thing. I'm pleased to say the experiment was a success and we managed to get the transposon to recombine with the translocation, which was nice. That was a very special day; that was very nice; that really felt like a part of history.