| Popis: |
As reported by Miller (1958c), A4iller and Stone (1962), and Miller and Roy (1963), the North American species D~osophila athnbnsca Sturtevant and Dobzhanslty, 1936, shows intraspecific variation in size and shape of the Y chronlosome. Three categories, designated Types 1, 2, and 3, were recognized. Type 1 is a large, J-shaped Y such as was originally found in this and other D. affinis subgroup species (Sturtevant and Dobzl~anslty, 1936). Type 2 is a medium-sized near-V. Type 3 is a large V-shaped Y associated both with a large V-shaped X' chromosome, which it closely resembles, and a rod-lilte X', which appears to be homologous to the 4th Chromosome of other D. athabnsca. This report is based on a study of new laboratory stoclts and wild specimens of D. athabasca acquired in che last few years. By means of these it has been possible to extend substantially the ltnown geographical ranges of the D. athabascn Y chromosome types and to provide some additional infornlation on the nature and relations of these types. W e wish to thank ochers who have provided D. nthnbasca material to augment our own: Dr. P. T. Ives (Amherst College) for the Amherst, Massachusetts, stoclt; Dr. Max Levitan (Woman's Medical College of Pennsylvania, Philadelphia) for furnishing abundant material from his 1963 collections of D. athnbnsca in Michigan, Ohio, and Pennsylvania; and A4r. Larrie E. Stone (Dana College, Blair, Nebraska) for the Bar Harbor, Maine, stoclt of D. athnbnsca. This work has been supported by National Science Foundation Grant GB-274 to the senior author. |
