Genetic differentiation versus geographical distance
Rookeries (breeding
areas) of California Sea Lions (Zalophus
californianus) are distributed linearly
along the west coast of North America.
In the first graph, Genetic Distance (measured as FST / (1 - FST) between pairs of populations is plotted versus their geographic distance. The regression line (solid line) is shown with ±95% confidence interval (dashed lines). FST / (1 - FST) measures genetic distance as genetic differentiation among population (FST) with respect to that among individuals within populations or with respect to the total (1 - (FIS + FIT)). Note that fractional FST among nearby rookeries (< 250 km) varies from 0.005 ~ 0.020, whereas those separated by > 1500 km range between 0.03 ~ 0.05. The conclusion is that Sea Lion populations show genetic isolation by distance.
In the second graph, note the theoretical relationship between pairwise FST and FST / (1 - FST): observed FST falls between 0.01 ~ 0.05.
In the first graph, Genetic Distance (measured as FST / (1 - FST) between pairs of populations is plotted versus their geographic distance. The regression line (solid line) is shown with ±95% confidence interval (dashed lines). FST / (1 - FST) measures genetic distance as genetic differentiation among population (FST) with respect to that among individuals within populations or with respect to the total (1 - (FIS + FIT)). Note that fractional FST among nearby rookeries (< 250 km) varies from 0.005 ~ 0.020, whereas those separated by > 1500 km range between 0.03 ~ 0.05. The conclusion is that Sea Lion populations show genetic isolation by distance.
In the second graph, note the theoretical relationship between pairwise FST and FST / (1 - FST): observed FST falls between 0.01 ~ 0.05.
Figures ©2013 by Sinauer; Graph & Text material © 2022 by Steven M. Carr