Lessios, H. A., Lockhart, S., Collin, R., Sotil, G., Sanchez-Jerez, P., Zigler, K. S., Perez, A. F., Garrido, M. J., Geyer, L. B., Bernardi, G., Vaquier, V. D., Haroun, R. & Kessing, B. D. 2012. Phylogeography and bindin evolution in Arbacia, a sea urchin genus with an unusual distribution. Molecular Ecology 21, 130-144.
Lessios, H. A.; Lockhart, S.; Collin, R.; Sotil, G.; Sanchez-jerez, P.; Zigler, K. S.; Perez, A. F.; Garrido, M. J.; Geyer, L. B.; Bernardi, G.; Vacquier, V. D.; Haroun, R.; Kessing, B. D.
Phylogeography and bindin evolution in Arbacia , a sea urchin genus with an unusual distribution
Among shallow water sea urchin genera, Arbacia is the only genus that contains species
found in both high and low latitudes. In order to determine the geographical origin of the
genus and its history of speciation events, we constructed phylogenies based on
cytochrome oxidase I and sperm bindin from all its species. Both the mitochondrial and
the nuclear gene genealogies show that Arbacia originated in the temperate zone of the
Southern Hemisphere and gave rise to three species in the eastern Pacific, which were
then isolated from the Atlantic by the Isthmus of Panama. The mid-Atlantic barrier
separated two additional species. The bindin data suggest that selection against
hybridization is not important in the evolution of this molecule in this genus. Metz
et al. in a previous publication found no evidence of selection on bindin of Arbacia and
suggested that this might be due to allopatry between species, which obviated the need
for species recognition. This suggestion formed the basis of the conclusion, widely
spread in the literature, that the source of selection on sea urchin bindin (where it does
occur) was reinforcement. However, the range of Arbacia spatuligera overlaps with that
of two other species of Arbacia, and our data show that it is hybridizing with one of
them. We found that even in the species that overlap geographically, there are no
deviations from selective neutrality in the evolution of bindin.
Keywords: gametic isolation molecules, Isthmus of Panama, marine barriers, mitochondrial