Estimates of gene flow between populations estimated using IMa.

Isthmus of Tehuantepec: Populations on either side of Isthmus of Tehuantepec.Los Tuxtlas: Los Tuxtlas populations mainly isolated from those along the Sierra Madre Oriental.Isthmus 2: Populations from Chiapas and Los Tuxtlas separated from populations west of the Isthmus of Tehuantepec (Isthmus 2).Chiapas Central Depression: Chiapas populations separated by the Central Depression.Chiapas-Los Tuxtlas: Populations of Los Tuxtlas separated from those in Chiapas and Guatemala.Oaxaca: Populations of the N Oaxacan highlands and Chimalapas region separated from the rest of the sampled populations.SMO-SMS: Populations of the Sierra Madre Oriental separated from populations along the Sierra Madre del Sur.Sample size refers to the number of sequences of each side of the barrier included in the analyses.