Biogeographic barriers are differentially permeable based on traits: movement of hypoxia tolerant mormyrid fish in the Lake Victoria basin (Data and code for publication)

Since they are hypoxia-tolerant, we hypothesized that they would have low genetic differentiation across the barrier more in line with air-breathing fish rather than other species which are not air-breathing. We discovered that the genetic differentiation in our focal species was very low, with FST values of 0.02 to 0.04, as opposed to other non-air-breathing fishes in previous work that ranged from 0.05 to 0.20, mostly above 0.10.

The values we found in our focal species were in fact much more comparable to obligately or facultatively air-breathing fishes that had FST values of near zero. We conclude that this barrier and other analogous ones should be understood as differentially permeable depending on the traits of the organisms crossing them, namely hypoxia tolerance in this case.