This book contains the papers presented at the Twenty-Seventh Annual Biology Division Research Conference which was held April 1-4, 1974 in Gatlinburg, Tennessee. The topic of the symposium was Mechanisms in Recombination and it follows by exactly twenty years the previous Gatlinburg Symposium on Genetic Recombination. During this interval, and the preceding years as well, the process of recombination has remained a central and tantalizing problem for geneticists. The subject assumes added significance with the recent appeal by a committee of leading scientists for a moratorium on the...