Introduction
The aim of this booklet is to provide simple explanations of the reasoning that lies behind the methodology of Physarum genetics. Genetic analysis in Physarum is, of course, primarily based on an understanding of the major genes influencing the life cycle, in particular the mat genes controlling plasmodium formation. The effects of these genes have been discussed many times before (e.g. Bailey 1995, 1997); their basic action is easy to understand and will be summarised only briefly. The P. polycephalum life cycle, however, is also subject to various aberrations which can confuse the unwary experimenter. We aim in this booklet to pass on many useful lessons learnt from painful experiences in the past. Since this is not intended to be a comprehensive review, we have concentrated on references that provide more detailed accounts of the methods discussed here. We have made no attempt to give credit to all those who have invented methods; we are, however, indebted and grateful to all these workers. Some additional methods may be found on the PhysarumPlus web page.