STUDIES OF LINKAGE IN POPULATIONS. I. ASSOCIATIONS OF SECOND CHROMOSOME INVERSIONS IN<i>DROSOPHILA ROBUSTA</i>

Abstract

Chromosomal aberrations have been studied for over thirty years. Nonetheless, no standard term has come into practice to designate in a general way the aberrations carried by an individual to correspond to the term "genotype" used in relation to the genes. In fact, many authors refer to inversion homozygotes or heterozygotes as "genotypes" when, in the usual sense of the term, it could easily happen that two individuals carrying the same inversions have different genotypes even for the loci em-EVOLUTION g: 62-74. March, 1955. Adult Drosophila robusta were collected during 1950, 1951, and 1952 (and some in 1953) in Crumpacker Woods near Blacksburg. Virginia and during 1952 and 1953 in Heth's Woods, located about two miles from Crumpacker. Crumpacker Woods was described in a previous publication (Levitan, 1951b). Heth's Woods contains much the same type of vegetation, but has been somewhat less disturbed by activities of man. The methods of collection in both woods were very similar to those described by Levitan (1951a). The reader is also referred to the above-mentioned papers (Levitan, 1951a and 1951b) for the methods used to analyze the 1950 collections for gene arrangement frequencies. The data suggested selectional differences between males and females carrying the same ar-62