443
microsatellites of the chloroplast genome due to the lack of nuclear specific primers
(Barrandeguy et al. 2011). More recently, a set of eight polymorphic nuclear microsatellite primers were developed for the species using a genomic library enriched
for tandemly repeated motifs (Barrandeguy et al. 2012; Barrandeguy and García
2016). At the same time, Feres et al. (2012) reported 14 polymorphic nuclear microsatellite markers for A. colubrina. Then, the genetic variability of Argentinean
populations of Anadenanthera colubrina var. cebil from Selva Pedemontana of the
Yungas and Alto Paraná Rainforest (Fig. 16.1) was analyzed using microsatellite
markers from nuclear and chloroplast DNA, determining an important historical
component in the distribution patterns of contemporary genetic variability in both
genomes (Barrandeguy et al. 2014). Complementary, 13 quantitative traits (eight
vegetative and five reproductive traits) were analyzed to characterize phenotypic
variability (García et al. 2014).
Chloroplast genome variability studies by means of cpSSRs (Barrandeguy et al.
2011; Barrandeguy et al. 2014; Goncalves et al. 2014) and cpPCR-RFLPs
(Goncalves et al. 2014) concluded that distribution patterns of chloroplast genetic
diversity in the studied populations were defined by the action of genetic drift. The
F ST fixation index indicated a strong genetic structuring because it reached a value
of 0.95, being statistically significant at a 95% confidence level (p < 0.05), while the
Bayesian spatial model established that the most probable number of clusters was
four (P (k = 4) = 0.99), with the individuals assigned to each cluster presenting the
same geographical origin (Goncalves et al. 2014). In this way, the high level of
population genetic structure detected in chloroplast genome would be explained by
absence of seed-mediated gene flow between populations (Goncalves et al. 2014).
Combined analysis of genetic structure for both nuclear and chloroplast DNA
showed that approximately 90% of the nuclear genetic variation was detected within
populations, while the remaining variation was equally distributed among populations and phytogeographic provinces (~5%). Nearly 70% of the chloroplast genetic
variation was found between the Yungas and Alto Paraná Rainforest, and 25% of
variation was observed among populations. The estimates of global F ST were statistically significant and indicated genetic differentiation in both genomes. According
to Wright’s qualitative guidelines for the interpretation of F ST (Hartl and Clark
2007), these populations are moderately structured at the nuclear genome
(F ST = 0.11), and they are highly structured at the chloroplast genome (F ST = 0.95).
The highest values of pairwise F ST -based on nuSSRs were observed between populations of the different phytogeographic provinces.
Also, two nuclear clusters were defined by the Bayesian model. Individuals were
assigned to these clusters according to their phytogeographic province of origin
(Fig. 16.6a). The intra-province-specific analyses found differentiation among the
populations of the Alto Paraná Rainforest, but no differentiation among those of the
Yungas (Fig. 16.6b). Also, six chloroplast clusters were defined by the Bayesian
model [log(ml) = 0.957]. Individuals were assigned to each cluster according to
their chloroplast haplotypes (Fig. 16.7a). The dendrogram showed two main groups
of haplotypes corresponding to the phytogeographic origin of the individuals
(Fig. 16.7b): one group integrated by the clusters 3, 4, and 6 containing all
16 Peteribí (Cordia trichotoma), Lapacho Rosado (Handroanthus impetiginosus)...
microsatellites of the chloroplast genome due to the lack of nuclear specific primers
(Barrandeguy et al. 2011). More recently, a set of eight polymorphic nuclear microsatellite primers were developed for the species using a genomic library enriched
for tandemly repeated motifs (Barrandeguy et al. 2012; Barrandeguy and García
2016). At the same time, Feres et al. (2012) reported 14 polymorphic nuclear microsatellite markers for A. colubrina. Then, the genetic variability of Argentinean
populations of Anadenanthera colubrina var. cebil from Selva Pedemontana of the
Yungas and Alto Paraná Rainforest (Fig. 16.1) was analyzed using microsatellite
markers from nuclear and chloroplast DNA, determining an important historical
component in the distribution patterns of contemporary genetic variability in both
genomes (Barrandeguy et al. 2014). Complementary, 13 quantitative traits (eight
vegetative and five reproductive traits) were analyzed to characterize phenotypic
variability (García et al. 2014).
Chloroplast genome variability studies by means of cpSSRs (Barrandeguy et al.
2011; Barrandeguy et al. 2014; Goncalves et al. 2014) and cpPCR-RFLPs
(Goncalves et al. 2014) concluded that distribution patterns of chloroplast genetic
diversity in the studied populations were defined by the action of genetic drift. The
F ST fixation index indicated a strong genetic structuring because it reached a value
of 0.95, being statistically significant at a 95% confidence level (p < 0.05), while the
Bayesian spatial model established that the most probable number of clusters was
four (P (k = 4) = 0.99), with the individuals assigned to each cluster presenting the
same geographical origin (Goncalves et al. 2014). In this way, the high level of
population genetic structure detected in chloroplast genome would be explained by
absence of seed-mediated gene flow between populations (Goncalves et al. 2014).
Combined analysis of genetic structure for both nuclear and chloroplast DNA
showed that approximately 90% of the nuclear genetic variation was detected within
populations, while the remaining variation was equally distributed among populations and phytogeographic provinces (~5%). Nearly 70% of the chloroplast genetic
variation was found between the Yungas and Alto Paraná Rainforest, and 25% of
variation was observed among populations. The estimates of global F ST were statistically significant and indicated genetic differentiation in both genomes. According
to Wright’s qualitative guidelines for the interpretation of F ST (Hartl and Clark
2007), these populations are moderately structured at the nuclear genome
(F ST = 0.11), and they are highly structured at the chloroplast genome (F ST = 0.95).
The highest values of pairwise F ST -based on nuSSRs were observed between populations of the different phytogeographic provinces.
Also, two nuclear clusters were defined by the Bayesian model. Individuals were
assigned to these clusters according to their phytogeographic province of origin
(Fig. 16.6a). The intra-province-specific analyses found differentiation among the
populations of the Alto Paraná Rainforest, but no differentiation among those of the
Yungas (Fig. 16.6b). Also, six chloroplast clusters were defined by the Bayesian
model [log(ml) = 0.957]. Individuals were assigned to each cluster according to
their chloroplast haplotypes (Fig. 16.7a). The dendrogram showed two main groups
of haplotypes corresponding to the phytogeographic origin of the individuals
(Fig. 16.7b): one group integrated by the clusters 3, 4, and 6 containing all
16 Peteribí (Cordia trichotoma), Lapacho Rosado (Handroanthus impetiginosus)...