Genetic estimates of population structure and gene flow: Limitations, lessons and new directions

Molecular phylogeography of the Chagas’ disease vector Triatoma infestans in Argentina

“…However, it is important to distinguish between current and historical levels of gene flow. In this regard, the estimates of gene flow and migration rates via Wright's F ST statistic (a measure of the variance of gene frequencies between populations) represent evolutionary averages, rather than contemporaneous patterns of dispersal (Bossart and Prowell, 1998;Palsboll, 1999), whereas assignment methods have the potential to provide direct estimates of real-time dispersal through the detection of individual immigrants . Considering that historical events can leave imprints on the distribution of genetic variability (Ibrahim et al, 1996) that can last for many generations (Nei et al, 1975), and the important role of genetic drift generating genetic differentiation among populations, it seems that the degree of current dispersion is not enough to produce a homogeneous metapopulation.…”

The dispersal rate of a beetle, Osmoderma eremita, living in tree hollows

“…This could be seen as a consequence of the metapopulations in small stands being too small to be able to persist in the long run, and the dispersals between stands being too rare to influence the habitat occupancy. For O. eremita, gene flow estimates have a major shortcoming, as such an analysis cannot distinguish between ongoing and historical gene flow (Slatkin 1987;Bossart and Pashley Prowell 1998). In Sweden, the populations of O. eremita have probably been reduced and isolated within the last 60 generations, as its habitat has decreased and become fragmented especially at the beginning of the 19th century (Eliasson and Nilsson 1999).…”

The breeding system and population structure of the termite Reticulitermes grassei in Southwestern France

“…Detailed knowledge of the genetic structure of populations can yield significant insights into a suite of ecological and evolutionary processes (reviewed in Neigel, 1997;Bossart and Prowell, 1998). For social organisms, genetic structure assumes additional significance not only for the evolution of social behaviour, but also for the evolution of multiple-queen societies, reproductive skew, sex ratio conflict, conflict over growth versus reproduction, and worker reproduction (reviewed in Pamilo et al, 1997;Ross, 2001;Sundströ m and Boomsma, 2001;Mehdiabadi et al, 2003).…”