Mitochondrial DNA variation in screwworm

Abstract

. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used to characterize mitochondrial DNA (mtDNA) variation in screwworms, Cochliomyia hominivorax, and secondary screwworm, C. macellaria, from the Caribbean, North America and South America . Four amplicons, totaling 7 .1 kb, were analysed with sixteen restriction enzymes . A total of 133 restriction sites was observed in the two species, 104 in C. hominivorax, of which nineteen were variable, and ninetyfive in C. macellaria, none of which was variable . Fourteen mtDNA haplotypes were observed among eighteen C. hominivorax examined . Mean divergence between C . h o m i n i v o r a x h a p l o t y p e s ( d ) w a s 0 . 0 0 6 4 substitutions per base-pair and genotypic diversity (G) was 0 .97 . Mean divergence between C. hominivorax and C. macellaria was 0 .0824 . Cochliomyia hominivorax haplotypes could be divided into three assemblages representing North America, South America and Jamaica, based on UPGMA clustering with d values . The assemblages did not exhibit complete geographic fidelity . These data were discordant with previously published allozyme data indicating little differentiation between screwworm populations . A scenario invoking historically isolated populations coming into contact with the introduction and movement of European livestock is proposed to explain the observed population structure of screwworm.

Genetic Relationships Among <I>Aedes aegypti</I> (Diptera: Culicidae) Populations from Argentina Using Random Amplified Polymorphic DNA Polymerase Chain Reaction Markers

“…This finding was also indicated in the dendrogram generated from data of RAPDs using the primers for identifying screwworms from other species. These results differ somewhat from the conclusions made by Taylor et al (1996), who divided C. hominivorax populations into 3 assemblages (North and Central America, South America, and Jamaica) but were using RFLP of mtDNA and had fewer samples and fewer bands for analysis.…”

A transgenic male-only strain of the New World screwworm for an improved control program using the sterile insect technique

“…Within Panama, Cochliomyia macellaria is the most closely related species of Calliphorid. This species is broadly sympatric with C. hominivorax across Central and South America [16, 17]. Although the two species have not been reported to hybridize in the wild and previous studies showed that they mate very rarely in caged settings, producing no hybrid offspring [18, 19], we studied the potential for transgenic C. hominivorax males to mate with wild type C. macellaria females in the laboratory.…”

Characterization and utilization of microsatellite loci in the New World screwworm fly, Cochliomyia hominivorax

“…Flies from Jamaica may also be distinct, but support for this is less clear‐cut. Previous molecular studies on flies from this region support the suggestion that C. hominivorax from Jamaica may be genetically distinct (Taylor et al , 1996).…”