1. Department of Cell, Developmental and Integrative Biology, University of Alabama Birmingham, Birmingham, Alabama 35205; Email: kjoyce@uab.edu.
2. Department of Biological Sciences, Auburn University, Auburn, Alabama 36949; Email: (MMH) mzh0031@auburn.edu; and (CG) guyercr@auburn.edu. Send reprint requests to CG.
3. Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee 37614; Email: potterjc@etsu.edu.