Genetics and systematics of North American populations ofMorchella

Abstract

Our knowledge of the genetics and systematics of the genus Morchella in North America has increased greatly because of many recent field and laboratory studies. Field studies have expanded distribution records and provided insights on ascoma development. More detailed morphological studies have improved species descriptions and simplified species identification. Mating studies between monosporous strains and the formation of presumptive heterokaryons have given evidence for species delimitation. The isolation of chemical products and antigen comparisons using ELISA have provided additional support for species concepts. Electrophoretic studies of allelic variation have given insights into the genetic structure of morels from different geographical areas. Sequence data from the nuclear large rDNA (28S) have been used to infer phylogenetic relationships among species. Additional insights have been obtained from physiological and environmental studies on sclerotium formation that have enabled the production of ascoma in culture. This has led to the filing of patents, commercial production, and the availability of growing kits. Key words: Morchella, systematics, genetics, North America, review.