61
by inspecting regions of the genome with a higher mutation rate. Therefore, the
genetic diversity detected with the chloroplast DNA markers, with information provided by nuclear microsatellites and isozyme markers, was combined.
A first approach through the screening of the genetic variation with isozyme
markers in 20 Argentine populations revealed higher levels of diversity in two populations from western areas (Hua Hum at Lake Lácar basin and Boquete at Lake
Lolog basin) and moderate but significant population differentiation (δ = 0.047,
F ST = 0.052; Marchelli and Gallo 2004). Then, species-specific nuclear microsatellites (Azpilicueta et al. 2004; Marchelli et al. 2008) were used to genotype individuals from 14 populations confirming the high diversity of the western populations
(Azpilicueta et al. 2013).
For the identification of hotspots of genetic diversity and to prioritize conservation activities, it is ideal to measure allelic richness (Petit et al. 1998) which is
highly sensitive to past demographic changes. Rarefaction provides unbiased estimates of allelic richness with great precision and statistical power (Leberg 2002).
Accordingly, nine populations that were genotyped with the three markers (chloroplast DNA, isozymes and microsatellites) were selected, and the allelic richness
(R g ) in each population after rarefaction to the lowest sample size (g) for all three
markers was estimated. For prioritization and identification of the most diverse populations (hotspots of genetic diversity), a standardized allelic richness (R gst ) was
calculated as described in Marchelli et al. (2017). Population Hua Hum at the west
of Lake Lácar holds the highest genetic diversity (Fig. 3.3b), and accordingly, conservation actions were taken (Gallo et al. 2009). Another interesting result is the
decreasing trend in allelic richness from west to east detected in the populations of
Lake Lácar basin, which suggests a possible migration route (Fig. 3.3a, b) (Marchelli
et al. 2017).
The mating system and the extent of pollen flow are two of the most important
genetic features that determine the genetic structure of plant populations, and both
are crucial for the design of conservation and management strategies. The mating
system is both cause and effect of the pollen flow dynamics, defining the distribution of genetic variation within and among populations (e.g. Holsinger 2000). Thus,
it is of considerable relevance to many areas of evolutionary and applied genetics
including management (Neale and Adams 1985) and conservation practices (e.g.
Burczyk et al. 1996). The mating system of raulí was characterized by high estimates of both single-locus (ts = 0.952) and multilocus (tm = 0.995) outcrossing
rates, and the multilocus rate was not significantly different from unity (Marchelli
et al. 2012). The estimated rate of biparental inbreeding (tm−ts = 0.043; SD = 0.026)
was very low, and the correlated paternity rate was rp = 0.101 (SD = 0.022), translating into a number of effective fathers per mother tree of Nep = 9.9. The estimated
average distance of pollen dispersal calculated with the indirect methods TwoGener
(Smouse et al. 2001) and Kindist (Robledo-Arnuncio et al. 2006), in one population
at the Lake Tromen basin was very short (δ = 34 m), but the dispersal kernel was
fat-tailed, and therefore long-distance events are expected (Marchelli et al. 2012).
Notwithstanding, the cumulative fraction of pollination suggests that vast majority
3 Raulí (Nothofagus alpina = N. nervosa): The Best Quality Hardwood in Patagonia
by inspecting regions of the genome with a higher mutation rate. Therefore, the
genetic diversity detected with the chloroplast DNA markers, with information provided by nuclear microsatellites and isozyme markers, was combined.
A first approach through the screening of the genetic variation with isozyme
markers in 20 Argentine populations revealed higher levels of diversity in two populations from western areas (Hua Hum at Lake Lácar basin and Boquete at Lake
Lolog basin) and moderate but significant population differentiation (δ = 0.047,
F ST = 0.052; Marchelli and Gallo 2004). Then, species-specific nuclear microsatellites (Azpilicueta et al. 2004; Marchelli et al. 2008) were used to genotype individuals from 14 populations confirming the high diversity of the western populations
(Azpilicueta et al. 2013).
For the identification of hotspots of genetic diversity and to prioritize conservation activities, it is ideal to measure allelic richness (Petit et al. 1998) which is
highly sensitive to past demographic changes. Rarefaction provides unbiased estimates of allelic richness with great precision and statistical power (Leberg 2002).
Accordingly, nine populations that were genotyped with the three markers (chloroplast DNA, isozymes and microsatellites) were selected, and the allelic richness
(R g ) in each population after rarefaction to the lowest sample size (g) for all three
markers was estimated. For prioritization and identification of the most diverse populations (hotspots of genetic diversity), a standardized allelic richness (R gst ) was
calculated as described in Marchelli et al. (2017). Population Hua Hum at the west
of Lake Lácar holds the highest genetic diversity (Fig. 3.3b), and accordingly, conservation actions were taken (Gallo et al. 2009). Another interesting result is the
decreasing trend in allelic richness from west to east detected in the populations of
Lake Lácar basin, which suggests a possible migration route (Fig. 3.3a, b) (Marchelli
et al. 2017).
The mating system and the extent of pollen flow are two of the most important
genetic features that determine the genetic structure of plant populations, and both
are crucial for the design of conservation and management strategies. The mating
system is both cause and effect of the pollen flow dynamics, defining the distribution of genetic variation within and among populations (e.g. Holsinger 2000). Thus,
it is of considerable relevance to many areas of evolutionary and applied genetics
including management (Neale and Adams 1985) and conservation practices (e.g.
Burczyk et al. 1996). The mating system of raulí was characterized by high estimates of both single-locus (ts = 0.952) and multilocus (tm = 0.995) outcrossing
rates, and the multilocus rate was not significantly different from unity (Marchelli
et al. 2012). The estimated rate of biparental inbreeding (tm−ts = 0.043; SD = 0.026)
was very low, and the correlated paternity rate was rp = 0.101 (SD = 0.022), translating into a number of effective fathers per mother tree of Nep = 9.9. The estimated
average distance of pollen dispersal calculated with the indirect methods TwoGener
(Smouse et al. 2001) and Kindist (Robledo-Arnuncio et al. 2006), in one population
at the Lake Tromen basin was very short (δ = 34 m), but the dispersal kernel was
fat-tailed, and therefore long-distance events are expected (Marchelli et al. 2012).
Notwithstanding, the cumulative fraction of pollination suggests that vast majority
3 Raulí (Nothofagus alpina = N. nervosa): The Best Quality Hardwood in Patagonia