Inferred highest probability of population migration rates (represented as 2 Nm) between adjacent populations of S-RED and BLUE were effectively zero from S-RED to BLUE (90% highest posterior density, HPD: 0 0.34), but positive (albeit low) from BLUE into S-RED (0.29, 90% HPD: 0.05 0.61).
The study areas had very low population migration rates.
Post-divergence migration (in each direction), m = m/µ is converted to population migration rate (2 Nm) using highest posterior density (HPD) estimates of θ (2 Nm = θ×m/2; Hey and Nielsen, 2004).
This is a particular concern when estimating gene flow between species rather than populations, since in these cases effective population size are typically high and migration rates low, which implies that equilibrium conditions will take a very long time to be reached [ 9].
This difference between species corresponds to theoretical expectations of faster approach to equilibrium in populations connected by higher migration rates (Whitlock and McCauley 1999).
Currently, the extent of gene flow among stream and reservoir populations of C. lutrensis is unknown, but high migration rates among populations could limit the extent of local adaptation in reservoir habitats.
The highest migration rates of Druze with other populations were observed with Iranians and Turks, but still these migration rates were considerably lower in comparison to migration rates of other Near East populations among themselves (Figure 2).
In any case, our inferences based on the IM model seem to confirm and extend the previous trends by showing that expanding Bantu females most likely had both greater population sizes (N) and higher migration rates (m) (Table 4).
A general lack of IBD, at a regional scale to the west of the CMR, is typically considered to be the result of a large, stable population with historically recurring gene flow, which was further supported by the high migration rates among both populations and regions.
However, this hypothesis was rejected for sardines at the nuclear level because the hierarchical AMOVA failed to detect significant geographical structuring between the Atlantic and the Mediterranean sardine population samples, and high and even migration rates were observed between both basins.
