Mediterranean fruit fly, Ceratitis capitata (Wiedemann), mitochondrial DNA: genes and secondary structures for six t-RNAs

The mitochondrial genome of the mediterranean fruit fly, Ceratitis capitata

The complete sequence of the mitochondrial genome of Ceratitis capitata has been determined. The circular genome is 15 980 bp long and contains a standard gene complement, i.e. the large and small ribosomal RNA subunits, twenty-two transfer RNA (tRNA) genes and thirteen genes encoding mitochondrial proteins. When comparing the sequence to fragments previously sequenced from other isolates it becomes apparent that interstrain polymorphisms are not rare. These differences are potentially useful for the development of diagnostic tools for population analysis applications, such as determining the source of recent introductions. Moreover, they could help obtain a solution to the long-lasting controversy on the possible eradication of the Medfly from certain locations.

Polymorphism within and between populations of Ceratitis capitata: comparison between RAPD and multilocus enzyme electrophoresis data

Random amplified polymorphic DNA (RAPD) analysis and multilocus enzyme electrophoresis (MLEE) were used to assess genetic variability in six wild populations and in five laboratory strains of Ceratitis capitata. The RAPD technique reveals larger amounts of genetic variation than the conventional MLEE, and can improve discrimination within and between populations and strains. In our experimental conditions, RAPD analysis with four different primers produces 174 polymorphic bands out of 176, while MLEE analysis at 26 enzyme loci scores 74 alleles. RAPD fingerprints are peculiar to African flies, while different laboratory strains have similar patterns, independently of their origins. The results obtained by these two methods are significantly correlated, and are in agreement with the general trend of decreasing variability from African populations towards the peripheral and laboratory ones. UPGMA dendrograms derived from MLEE (protein) and RAPD (DNA) data show that a major part of intraspecific variability involves the differentiation of central vs. peripheral populations.

Analysis of mitochondrial DNA and development of PCR-based diagnostic molecular markers for Mediterranean fruit fly (Ceratitis capitata) populations

A 2.99 kb mtDNA fragment containing two variable restriction endonuclease sites (EcoRV and XbaI) was subcloned and sequenced from the Mediterranean fruit fly (Ceratitis capitata). This fragment represents approximately one-fifth of the entire mitochondrial sequence. The sequence was aligned with the comparable region from Drosophila yakuba and Anopheles gambiae, resulting in 81.8% and 76.7% identity at the nucleotide level, and 77% and 67.7% identity, respectively, at the amino acid level. The sequenced region includes the complete genes for NADH dehydrogenase 4, NADH dehydrogenase 4L, NADH dehydrogenase 6, and transfer RNAs for proline, threonine and histidine, and part of the genes for NADH dehydrogenase 5 and cytochrome b. Oligonucleotide primers were designed to asymmetrically bracket each of two variable restriction endonuclease sites to allow PCR amplification and subsequent restriction endonuclease analysis of individual fly samples.

Mitochondrial DNA restriction map for the Mediterranean fruit fly, Ceratitis capitata

Molecular genetic research on the Mediterranean fruit fly, Ceratitis capitata, will provide tools to permit determination of source populations for new pest infestations. Restriction fragment length polymorphism (RFLP) of mitochondrial DNA provides some interpopulation discrimination. A restriction map, including the informative variable EcoRV and XbaI restriction sites, is constructed for the Mediterranean fruit fly, and several restriction sites are associated with specific gene regions based on polymerase chain reaction-RFLP and sequence analyses. A partial sequence of the mitochondrial 16S ribosomal RNA gene is reported.