The research reported in this volume illustrates the utility of incorporating cytogenetic tools into biological studies. Somatic chromosome identification is now becoming routine in selected plant species, and the utility of this technique will increase as it expands to other taxa. Individual genes or DNA fragments can be localized to chromosomes in combination with chromosomal identification techniques, which bypasses the need for multiple generations of genetic analysis to map molecular markers to chromosomal positions. The identity of individuals with chromosomal changes can be determined in root tip metaphase spreads, with subsequent growth of these individuals for further genetic and molecular analyses. These new techniques have allowed examination of chromosomal behavior in meiotic and somatic preparations at the whole-genome level. They are also the basis for studies of changes in chromosomal structure or transposable elements in different cells of a single tissue. The studies in this volume illustrate many of these applications and the diversity of research avenues they open up. This publication will be of interest to cytogeneticists, cytologists, cell biologists and evolutionary biologists.