RECOMBINATION AS A POSSIBLE MAJOR CAUSE OF GENETIC-HETEROGENEITY IN ANTICARSIA-GEMMATALIS NUCLEAR POLYHEDROSIS-VIRUS WILD POPULATIONS

Thirteen different types of restriction profiles were obtained by the analysis of 32 cloned DNAs isolated by limiting dilution from a wild population of Anticarsia gemmatalis nuclear polyhedrosis virus (AgMNPV) using EcoRI and BglII. Five restriction sites located at 4.6, 38.5, 67.7, 70.6, 97.7 map unit (m.u.) of the AgMNPV DNA physical map, segregating in the wild Brazilian virus population B87, were identified. The five restriction markers (4 EcoRI and 1 BglII sites) and an extra insertion/deletion marker located between 88.7 and 94.3 m.u. were used to label the genomes of isolated restriction types. Double infection of Spodoptera frugiperda Sf9 cells with pairs of purified AgMNPV genotypes very rapidly resulted in a majority of recombinants among progeny viruses. The highest score obtained was 39 recombinant clones out of 49 cloned DNAs isolated from the progeny 15 days post double infection with a multiplicity of infection of 8 for each parental genotype. The predominant reassociation of neutral DNA genomic markers following double infection of Sf9 cells by pairs of parental AgMNPVs indicates the potency of intrapopulation genetic recombination in a wild isolate to redistribute DNA sequences in the genetic pool of this virus.