Molecular ecology is a broad area of research that embraces topics as varied as population genetics, conservation genetics, molecular evolution, behavioural ecology and biogeography. Although somewhat varied, the areas of research within molecular ecology are united by the fact that they all use molecular genetic data to help us understand the ecology and evolution of organisms in the wild. This article provides an introductory overview of molecular ecology, and includes discussions of molecular markers, population genetics and phylogeography. It also contains examples that show how this discipline is relevant to several areas of applied science, including wildlife forensics and the management of invasive species.
Molecular Ecology
Joanna R Freeland, Trent University, Peterborough, Ontario, Canada
Sarah Anderson, University of Kent at Canterbury, Canterbury, Kent, UK
Published online: September 2007
DOI: 10.1002/9780470015902.a0003268
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Figure 1. Part of the DNA sequence that comprises the mitochondrial genome of the common green darner dragonfly (Anax junius). The large peaks are ‘read’ as individual bases, and the corresponding sequence is written along the top of the image.
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Figure 2. Electropherogram of a raccoon microsatellite multiplex which shows the sizes of the microsatellite alleles at four separate loci. The x-axis represents the sizes of the fragments (in basepairs), and the y-axis represents the intensity of the fluorescent signal. Each of the four microsatellite loci are represented as the four sets of peaks, with each set consisting of two separate peaks. Alleles from the first and third loci are labelled with HEX (green dye), and those from the second and fourth loci are labelled with 6-FAM (blue dye). Because all four markers display two peaks, this individual is heterozygous at each of these loci. An additional marker seen at the far right is a sex-specific marker and is labelled with HEX; the single peak indicates this individual has only one type of sex chromosome and is therefore female (see text). Reproduced by kind permission of C.I. Cullingham.
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Figure 3. A population bottleneck can have a lasting effect on genetic diversity. At time 0, this population was relatively large and had eight alleles at a particular locus (reprented by eight different colours). At time 1, the population experienced a bottleneck when it was reduced in size; only two of the alleles were maintained in the population during this time. By time 2, the population had regained its former size, but its genetic diversity was still much lower than it had been at time 0.
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Figure 4. Hypothetical situation in which phylogeographic theory is used to identify the most likely source of an invasive population (population 1) in the UK. (a) Map showing the location of all populations from which individuals were sequenced. (b) Phylogenetic tree showing the genetic relationships between these populations, based on their overall genetic similarity. Because population 1 is genetically closest to populations 5, 4 and 6, we may conclude that it was most likely to have been introduced from the Iberian peninsula. Without phylogeographic data we may have presumed that the UK invader originated from the closest source population (population 2 or 3).
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| Further Reading | |
| book Avise JC (2000) Phylogeography: The History and Formation of Species. Cambridge, MA: Harvard University Press. | |
| book Beebee TJC and Rowe G (2004) Introduction to Molecular Ecology. New York: Oxford University Press. | |
| book Frankham R, Ballou JD and Briscoe DA (2002) Introduction to Conservation Genetics. Cambridge: Cambridge University Press. | |
| book Freeland J (2005) Molecular Ecology. Chichester: Wiley. | |
