Genetic methods are today used in almost every part of biology and are generally regarded as a set of indispensable analytical and practical tools. This is, however, a very narrow aspect of the subject. The logic of genetics – originating in the fidelity of DNA replication, the stability of mitosis, and the dynamic properties of meiosis – hides deep evolutionary and functional complexities. This insight is the basis for our research in transmission, population and chromosomal genetics. Our work concerns the application of genetics to plant breeding and medical genetics, as well as to basic science. In particular we have much experience with combining the results from empirical studies with statistical and mathematical investigations.