Figure 1.
Geographical distribution of sampled populations of Dioscorea humilis in Chile (Table 1) and Bayesian analyses of the genetic structure of 15 populations of D. humilis subsp. humilis and two populations of D. humilis subsp. polyanthes based on nuclear microsatellite data.
The mean proportion of membership of each predefined population to each of the A, three (K = 3), and B, five (K = 5), most likely inferred genetic clusters is shown. The dotted line indicates the location of the Maipo river. Chilean administrative regions: IV, Coquimbo, V, Valparaíso, M, Metropolitana, VI, Libertador General Bernardo O’Higgins, VII, Maule, and VIII, Bío-Bío. Geographical ranges of five climatic zones in central Chile from Castillo et al., [20] are superimposed on the maps. From North to South: semiarid Mediterranean (white), sub-humid Mediterranean (vertical shading), humid Mediterranean (horizontal shading), hyper humid Mediterranean (diagonal shading) and eastern Andean Continental (solid grey). Map contour constructed from spatial data retrieved from http://www.diva-gis.org/gdata.
Table 1.
Population data and genetic diversity indices of 17 Chilean populations of Dioscorea humilis for eight nuclear microsatellite loci and overall estimates for taxonomic and geographical population groups.
Table 2.
Analyses of molecular variance (AMOVA) of Dioscorea humilis populations based on microsatellite data.
Table 3.
Plastid combined trnTL- trnLF haplotype diversity analysis of D. humilis populations and geographical/genetic groups.
Figure 2.
Principal Coordinates Analysis (PCO) showing the genetic relationships among populations of Dioscorea humilis based on DA genetic distance [30].
Populations of D. humilis subsp. polyanthes (Dhp01, Dhp02), yellow circles; northern populations of Dioscorea humilis subsp. humilis (Dhh01 to Dhh08), blue circles; southern populations of D. humilis subsp. humilis (Dhh09 to Dhh15), green circles.
Figure 3.
Isolation by distance analyses.
Correlation between log-transformed pairwise geographical distances and linearized FST values [28] among populations of D. humilis. A. D. humilis s.l. where open circles represent pairwise comparisons among populations of D. humilis. subsp. humilis and black squares represent pairwise comparisons among populations of D. humilis. subsp. humilis and D. humilis subsp. polyanthes. Correlation between matrices was r = 53.74%, p = 0.001 for D. humilis s.l. and r = 41.61%, p = 0.004 for D. humilis subsp. humilis B. IBD analyses within geographical groups of D. humilis susbp. humilis, where black circles represent pairwise comparisons among populations of the northern group (Dhh01-Dhh08) and grey circles represent pairwise comparisons among populations of the southern group (Dhh09-Dhh15). Correlation between matrices was r = 29.62%, p = 0.080 and r = 0.47%, p = 0.420 for the northern and southern groups, respectively.
Figure 4.
Plastid haplotype diversity in Dioscorea humilis.
A. Geographical distribution of eight chloroplast haplotypes in 17 populations of Dioscorea humilis. Pie charts indicate relative frequencies of each haplotype in each population. The dotted line indicates the location of the Maipo river. Chilean administrative regions and climatic regions are indicated as in Fig. 1. B. Parsimony Network showing the relationships among eight haplotypes. Black dots indicate unsampled or extinct haplotypes. The size of the circles or squares is proportional to the number of sequences representing each haplotype, and is indicated in parentheses when higher than one. Map contour constructed from spatial data retrieved from http://www.diva-gis.org/gdata.
Figure 5.
Environmental Niche Modelling (ENM) of Dioscorea humilis estimated under Last Interglacial (LIG) (A), Last Glacial Maximum (LGM) (B) and current (C) climate conditions.
In orange, northern D. humilis subsp. humilis genetic group, in blue, southern genetic group and in bright green, overlapping areas among predicted distributions. A tenth percentile threshold was applied. Black circles: northern populations of D. humilis subsp. humilis (Dhh01 to Dhh08); grey circles: southern populations of D. humilis subsp. humilis (Dhh09 to Dhh15). The black dashed line indicates the location of the Maipo river. The grey dashed line in B indicates the approximate extent of the ice sheet during the LGM after [5]. Map contours constructed from spatial data retrieved from http://www.diva-gis.org/gdata.