A MOLECULAR APPROACH TO THE ROLE OF HISTORICITY IN EVOLUTION. I. EXPERIMENTAL DESIGN WITH ENZYME POLYMORPHISM IN...

I investigate the role of the past history (characterized by two inverse sequences of three environments) experienced by Drosophila melanogaster populations, on the allozyme frequencies at four loci (α-Gpdh, Adh, Est-6, Pgm) in a common and constant final environment. The only locus for which an effect of past history was detected is Adh. Although not unambiguous, this result is discussed in terms of interactions between this locus and other polymorphic loci. For Est-6 and Pgm, no influence of past history was seen. As for α-Gpdh, the substantial heterogeneity between replicate populations belonging to the same historical series is probably due to a hitch-hiking effect of genes surrounding this locus. More generally, the role of historicity (i.e., the factors originating from the past history of a population and being accountable for its contemporary evolution) in creating genetic diversity between populations and among species is discussed.