Microsatellites: A powerful genetic marker for fern research

Abstract

A large number of studies on fern biology have traditionally been carried out by allozyme electrophoresis and, more recently, by dominant nuclear genetic markers. However, the low sensitivity of the former and the inability to reveal heterozygotes of the latter constitute important obstacles for detailed studies on several life traits of ferns. Microsatellites, short tandem repeats of nucleotides present in most eukaryote genomes, can cover those deficiencies thanks to their hypervariability and codominant inheritance. This PCR-based technology has been widely used to study vertebrates and angiosperms with great success, but only a few works applying it to ferns have been published in the last decade. These studies allow us a glimpse of the great promise that microsatellites hold to address multiple biological issues unresolved by less sensitive markers, such as fine-scale genetic diversity and recent evolutionary history. Beyond some hindering factors in results interpretation, the most notable drawback of microsatellites is that they are still expensive to develop, although costs are becoming progressively cheaper as more laboratories and companies provide this service. The peculiarities of fern life and evolutionary histories make microsatellites even more interesting markers, as this technology can be used to explore many traits of fern biology. Microsatellites are, therefore, shaping up as a powerful genetic marker for fern research which is well worth the investment. Despite their fairly acquired popularity, it is surprising how this technology has been barely applied to study ferns, although the few reported cases show a successful -implementation. In this chapter, I will provide an overview of microsatellites which will hopefully be useful to researchers not familiarized with the technique but who feel that it could improve their science. First I will place microsatellites in the -context of genetic molecular markers and explain what are they and how to use them. Then I will focus on the published works which have used microsatellites, explaining in more detail my own experience with the technique, and present the advantages and disadvantages of working with this powerful marker. Finally, I will close the chapter with some future prospects for the role of microsatellites in fern research. My goal is thus to encourage fern scientists, particularly those concerned with fern population genetics, to consider microsatellites as a valuable opportunity for their work.