Intrapopulational genetic differentiation in Anopheles (N.) darlingi Root,1926 (Diptera : Culicidae) in the Amazon region

Four natural Amazonian Anopheles darlingi populations were analyzed for 19 loci, 12 of which showed variation, i.e., 68.4% of polymorphic loci. The Ar iquemes, Rondonia, population was the most variable, with a large number of alleles per locus (2.26 +/- 0.27) and high polymorphism (P = 63.15). The h ighest values of observed and expected intralocus heterozygosity were obser ved in the Manaus, Amazonas, population (Ho = 0.432 +/- 0.11; He = 0.375 +/ - 0.08), and the lowest in the Cachoeira Porteira, Para, population (Ho = 0 .236 +/- 0.09; He = 0.290 +/- 0.11). Wright's F-statistic revealed disequil ibrium caused by an excess of homozygotes, as shown by the F-is > F-st valu es (F-is = 0.083 > 0.026) reflecting intrapopulational differentiation. The four populations studied were genetically similar, as indicated by distanc e and similarity values. Chromosomal variation of Amazon population also di d not indicate geographical differentiation, and populations in the central region of the Amazon Basin showed high polymorphism in relation to the mar ginal populations, which were mainly monomorphic.