Optimizing sampling efforts for ex situ conservation of genetic variability of Dipteryx alataVogel
Melo et al. BMC Proceedings
Optimizing sampling efforts for ex situ conservation of genetic variability of Dipteryx alata Vogel
Dayane B Melo 3
José Alexandre F Diniz-Filho 2
Guilherme Oliveira 1
Ludmilla L Santana 0 5
Thannya N Soares 0 5
Lázaro J Chaves 4
Ronaldo V Naves 4
Rosane G Collevatti 0 5
Mariana P de C Telles 0 5
0 Laboratório de Genética & Biodiversidade, Depto. Biologia Geral , ICB, UFG , Brazil
1 Programa de Pós-Graduação em Ecologia & Evolução , ICB, UFG , Brazil
2 Depto. Ecologia, Universidade Federal de Goiás (UFG) , Brazil
3 Programa de Pós-Graduação em Agronomia (UFG) , Brazil
4 Escola de Agronomia & Engenharia de Alimentos , UFG , Brazil
5 Laboratório de Genética & Biodiversidade, Depto. Biologia Geral , ICB, UFG , Brazil
Background The “Baru” tree (Dipteryx alata Vogel) is an endemic species from the Cerrado biome, but widely distributed within the biome and abundant in several of its habitats [1].The species is also important in commercial terms for recover of degraded areas, and seeds are consumed in natura and are source of raw material for small and middle-sized food industries [2].Thus, a more detailed knowledge of its population variability and structure is needed for better establishing both in situ and ex situ conservation efforts. Data for such analyses can be provided by new molecular markers, such as microsatellites, whereas spatial analyses and optimization procedures can be applied to analyze these data and thus improve conservation efforts. Here we investigate the genetic variability within the germplasm bank of D. alata based on microsatellite data and compared it with a large sample of 25 widely distributed natural populations of the species. We then used a simulated annealing algorithm to find the smallest number of these natural populations that should be sampled to conserve the full genetic variability of the species.
Methods
We described the genetic variability of 816 individuals of
D. alata from 25 natural population widely distributed
in the Cerrado biome, and from 180 individuals
preserved in an active germoplasm bank, situated in the
“Escola de Agronomia e Engenharia de Alimentos”
Universidade Federal de Goiás, totalizing 996 individual
plants genotyped for 9 microsatellite loci. The origin of
the individuals in the bank is not known in detail, but it
is certain that they came from several localities from
Goiás State.
Overall description of genetic variability in the natural
populations and in the germoplasm bank was done by
percentage of polymorphic loci (P), mean number of
alleles per loci (A), expected heterozigosity under H-W
equilibrium (He) and observed heterosigozity (Ho).
Population structure and divergence among natural
populations were analyzed using FSTstatistics.
A simulated annealing algorithm, implemented in the
software SITES [
3
] was used to establish the minimum
number of local populations necessary to complement
the germoplasm bank so that all alleles (expressed as
present or absent in each local population) are
represented at least once (i.e., representation goal). The
search was performed using two hundred runs and
10,000,000 iterations for each run. The problem is
analogous to the ecological problem of finding a minimum
number of new conservation priority areas that
represent all species, after fixing a few already established
natural reserves (see [
4
]).However, there may be
frequently multiple combinations of local populations that
satisfy the representation goal, so the first 100 solutions
of SITES were also retained. The relative frequency of
each local population in the alternative optimized
solutions is an estimate of the “irreplaceability”, or relative
importance, of the populations to the overall goal of
representing the entire genetic variablity (alleles).
Results and discussion
The genetic variability of D. alata for the microsatellite
loci analyzed here was low compared with other forest
species in the same region (e.g., [
5
]). Out of the 9 loci,
on average 78% were polymorphic within natural
population, and 67% were polymorphic in the germplasm
bank. The mean number of alleles per loci were 2.7 and
4.4 for the natural populations and for the germplasm
bank, respectively. The He and Ho were equal to 0.36
and 0.30 for natural populations, and 0.36 and 0.23 for
the germoplasm bank. The FST was significant and equal
to 0.259, indicating a relatively high differentiation
among the local populations.
The simulated annealing revealed that only 4 local
populations, located in Mato Grosso and Mato Grosso
do Sul (Figure 1; 1-CMT. 5-AMS. 19-RAMT e
25CAMT), are necessary to represent all alleles that
appeared in the species, complementing in an optimum
way the genetic variability already present in the
germplasm bank. The solution is unique so that all these 4
local populations have 100% of irreplaceability.
Our analyses confirm that the germoplasm bank
currently established in the Universidade Federal de Goiá (...truncated)