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Résumé :
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A diverse range of novel molecular (DNA) markers are now available for entomological investigations. Both DNA and protein markers have revolutionized the biological sciences and have enhanced many fields of study, especially ecology. Relative to DNA markers, allozymes are cheap, often much quicker to isolate and develop, even from minute insects (aphids, thrips, parasitic wasps, etc.), and subsequently easy to use. They display single or multi-locus banding patterns of a generally easily interpretable Mendelian nature, and the statistics for their analysis are well established. DNA markers are also suitable for use with small amounts of insect material and can be used with stored, dry or old samples. They have an expanding range of applications, many involving intra- and interspecific discriminations. Like allozymes, they can be single or multilocus, whilst methods for their statistical analysis have recently been published. However, they can be considerably more expensive than allozymes, require more complex preparatory protocols, expensive equipment, may involve lengthy development procedures (e.g. isolating cloned oligonucleotides to develop primers to detect microsatellite regions) and some have complex multi-locus banding patterns which may be of a non-Mendelian nature (e.g. RAPDs, randomly amplified polymorphic DNA), and are in some cases, not easily repeatable. In this review we hope to inform the general reader about the methodology and scope of the main molecular markers commonly in use, along with brief details of some other techniques which show great promise for entomological studies. Thereafter, we discuss their applications including suitability for particular studies, the methods used to load and run samples, subsequent band detection, band scoring and interpretation, the reliability of particular techniques, the issues of safety involved, cost effectiveness and the statistical analyses utilized.
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