By Brendan Maher
Alex Schreiber, research associate at the Carnegie Institution of Washington embryology department, says he's into doing "simple experiments if at all possible." When your research subjects demand hundreds of pounds of salt, thousands of gallons of water, and dozens of 10-gallon containers of what he calls "concentrated salt water," essentially what's left when you remove both salt and water from seawater, simplicity is a welcome luxury.
Schreiber studies flatfish such as the southern flounder which metamorphose about two weeks post-fertilization from normal-swimming, normal-looking, symmetric larva, to bizarre, frying pan-shaped adults with two eyes on one side of their heads. As happens in frogs, which Schreiber studied as a postdoc with Carnegie staff scientist Donald Brown, the dramatic metamorphosis is mediated solely by thyroid hormone.
One hypothesis, Schreiber says, is that de-iodinases, the enzymes that activate or deactivate thyroid hormone, are asymmetrically expressed, "so ... the two sides ...
