Diversity in natural fern populations: Dominant markers as genetic tools

Abstract

Our aim, in the present chapter, is to provide a synthesis of the use of dominant markers in the Pteridophytes' genetics. We try to provide a -comprehensive review of the advantages and disadvantages of the selection of dominant markers as genetic tools, when compared to other molecular techniques -available. Dominant markers fulfill most of the ideal characteristics of a fingerprinting -technique as they are usually technically simple procedures, inexpensive, and allow fast data -acquisition. In addition, dominant markers are based in one of the fundamental characteristic of the DNA, the probability of sequence repetition due to the -existence of only four nucleotides, so these techniques are easily -transferable from one -organism to another as no prior genetic knowledge of each species is needed. However, the increasing availability of sequenced data due to the relative price decrease and apparition of new sequencing techniques together with their drawbacks have forced to ask: are dominant markers still useful? We do not try here to give a definitive answer to this question. We just want to point out that there is no perfect fingerprinting technique. Its choice is often a -compromise that depends on a number of material and species-related factors. The existence of previous genetic data in the species, the knowledge of close relatives, and the complexity of the genome are other factors that dramatically influence our selection. The resources of the laboratory, financial constraints, available expertise, time limitations, and, more importantly, the research pursued usually define our opinion about dominant markers. Our purpose in the present chapter is to provide a detailed review of strong points and drawbacks as well the areas where the -application of dominant markers has succeeded in answering questions in the genetically complex Pteridophytes.