Chromosomal Configurations of Oenothera Species antd Crosses and Their Probable Significance

Abstract

The purpose of this paper is to tabulate all chromosomal configurations of the Oenothera species and crosses that have so far been observed and to discuss the significance of chromosomal cohesion. The tabulations of each form include the name of the investigator, the year reported, and, if available, the source of material and the genetical constitution of each. The writer does not claim that these tables are complete in every instance, but an attempt is made to cover all the work available to date. Such a series of tables, it is felt, would be of great advantage in any attempt to understand the significance of closed circles so characteristic of the Oenothera species. In connection with each table there is given a brief discussion of the forms therein listed. In these discussions there are emphasized in particular two points based upon the data presented in these tables: (i) the variability in chromosomal configurations in any particular Oenothera species; and (2.) the assumption that closed circles are due to genic action and therefore inherited as are phenotypical characters. Table I (7 pairs) consists of nineteen different species, each of which, as observed by different investigators, has shown a complete pairing of the fourteen chromosomes. These nineteen Oenotheras consist of six species, three mutants, one half-mutant, six segregates, and three hybrid derivatives, some of which have been recognized