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Deep in the darkest recesses of a cell something determines its fate: How will it react to food or famine? Should it grow and divide? Into two identical daughter cells, or four daughters with mixed-up chromosomes?
Paul Magwene wants not only to know how a yeast cell decides to behave, but to watch it do so in real time. He studies a signalling pathway, a series of chemical reactions which transmits signals from the exterior of the cell to the nucleus. There it turns particular genes on or off, determining the cell's behavior. Paul tries to match genetic variation in this pathway to different cell fates.
Right now his lab is adapting a cool technique that will make yeast cells fluoresce when the pathway is stimulated. If it works, they can expose cells with different versions of the pathway to different stimuli, and watch how it lights up!
Meanwhile Paul is teaching himself to play the piano. He’s especially interested in creating music with algorithms or formal rules, just as DNA governs an organism by varying the sequence of four bases. Is there a G-C-A-T Symphony in his future?[more]
Before going to college John Mercer joined the Navy. See the world! Experience life! After much training John became an Electronics Technician-Reactor, 1st Class, on a nuclear submarine. He saw a lot of grey paint. Then he went to college and graduate school to study biophysics, and embarked on a different kind of fantastic voyage.
On this voyage John has descended to the level of DNA molecules and proteins, the technicians 1st class of the cell, to see how they evolve. Many powerful techniques exist for studying proteins: determining their three-dimensional structure, analyzing their chemistry, constructing mathematical models. You can manipulate their structure by changing some components, put the result into a yeast or bacterial cell, and sit back and watch as the generations roll by. By putting the same line of cells in different environments, you can see if your modified protein makes any difference to the cells' ability to adapt and ultimately evolve. John hopes one day to understand the selective pressures that cause proteins to change.
In the meantime, BEAT ARMY![more]
John Willis loves figuring things out--specifically, how the wildflower Mimulus adapts to different environments. Colonies adapt to different elevations, or degrees of drought, or soil types. Some have even evolved to live on highly contaminated soil near a copper mine. Which of their genes change, and do they change in many little ways or one big way? Why do some separated groups lose the ability to reproduce with their neighbors? Are the genes that help them adapt the same ones that prevent living hybrid offspring?
The Willis group tests this with "tricky crosses" between different varieties. If the copper mine variety mates with nearby types, the offspring all die. But when one parent is crossed to a third and their viable offspring to the other parent, it produces some living offspring and some that die. By analyzing which parts of the parents' chromosomes each type inherited, the lab can zero in on the killer gene. Scientists assumed that the copper-tolerant gene was the killer, but Willis recently showed that a near neighbor, which "hitchhiked" with copper tolerance into the population, was guilty.
The lab also uses tricky crosses to study a genetic arms race fought inside the seed, between the parents. But that’s a different story. [more]
The October 7 issue of Current Biology features an interview with Philip Benfey, describing his unconventional path to the research lab and the study of root development. Most interesting! [more]