(a) Data collection
For our mitochondrial π dataset, we compiled 1781 population-level
measurements of genetic diversity, while for Hdwe compiled 1871 diversity measurements. Collectively, these
observations came from 239 studies and represented 262 species in 82
families. For microsatellites, we recorded genetic diversity
(He ) from 3210 populations, 578 studies, and 341
species in 86 families. When recorded for the same population, nuclearHe was not strongly correlated with either
mitochondrial π or Hd(He -π rs = 0.242;He -Hd rs =
0.349) although π and Hd were positively related
to each other (π-Hd rs = 0.818)
(Fig. S1).
These nuclear and mitochondrial datasets represented populations from
across the globe, spanning all latitudes, every ocean basin, and a wide
array of environmental conditions (Fig. 1, S2 & S3). Coastlines in the
Northern hemisphere represented the most densely sampled regions in our
database. However, there were still a large number of diversity
estimates near the Equator, particularly in the Coral Triangle. While
the number of datapoints decreased towards the poles for both
mitochondrial and nuclear diversity, there were still a substantial
number of diversity estimates at latitudes greater than 60° N or S for
both mitochondrial (39 observations) and nuclear (311 observations)
diversity.