ASSOCIATION AMONG QUANTITATIVE, CHROMOSOMAL AND ENZYMATIC TRAITS IN A NATURAL-POPULATION OF DROSOPHILA-MELANOGASTER

A sample of 1 359 males and 1 259 females from a natural population of Drosophila melanogaster of the Canary Islands was simultaneously examined for wing length, inversion polymorphisms, and gene variation at 10 allozyme loci. Correlations and nonrandom associations between those genetic traits were estimated. In contrast to previous studies, large amounts of linkage disequilibrium have been found. Frequencies of significant gametic associations between linked and unlinked elements were 100% and 25%, respectively, for chromosome inversions, 81% and 4% for chromosome inversions, and allozymes, and 36% and 0% for pairs of allozymes. Temporal stability in chromosome and allozyme frequencies and the average number of alleles per locus rule out a recent bottleneck effect. Mean and coefficient of variation of wing length are correlated with the degree of heterokaryotypy (both negatively) and with the degree of heterozygosis (positively for the mean, negatively for the coefficient of variation), mainly implying chromosome 3 elements. Individuals with wing length above (or below) a standard deviation from the population mean showed characteristics for the other genetic traits which resembled those of northern (or southern) populations of the species.