Random amplified polymorphic DNA of screwworm fly populations (Diptera: Calliphoridae) from Southeastern Brazil and Northern Argentina

The screwworm fly Cochliomyia hominivorax is one of the most important agents of traumatic myiasis throughout neotropical regions. In this work, we optimized the technique of RAPD-PCR for these species and used it to study the genetic variability among seven populations (six from southeastern Brazil and one from northern Argentina) of C. hominivorax. RAPD fingerprints showed high variation for 12 primers used, revealing 209 presumptive loci of which 198 were polymorphic. Marker pattern relationships for these different populations were used to determine genetic relatedness, as well as to examine potential patterns of gene flow. Our interpretation of Lynch and Milligan's analogue of Wright's F (ST) was that C. hominivorax populations are genetically subdivided (F' (ST) for pooled samples = 0.122). Our data suggested that the subdivision detected in C. hominivorax populations by RAPD can be explained by the interplay of random factors affecting allele frequency changes. These results indicate that the RAPD-PCR technique is useful for revealing genetic variation in screwworm fly populations not detected by others techniques and can represent an efficient method for understanding the genetic structure and population genetic phenomena of this important pest.