Low genetic diversity and intrapopulation spatial genetic structure of the Atlantic Forest tree, Esenbeckia leiocarpa Engl. (Rutaceae)

Abstract

Abstract. Studies on population genetics are the key to designing effective in situ management plans for tree species, in particular, those subjected to pressure from anthropogenic processes, such as forest fragmentation and logging. To investigate genetic diversity, inbreeding and intrapopulation spatial genetic structure (SGS) in a fragmented population of the insect-pollinated tropical tree, Esenbeckia leiocarpa, we developed specific microsatellite markers for this species and mapped and sampled 100 individuals in a forest plot. Two issues were addressed in particular: (i) the level of genetic diversity, inbreeding and effective population size, (ii) whether intrapopulation spatial genetic structure exists. Among the 14 loci developed, we only used the three that presented polymorphism to estimate the genetic parameters. Genetic diversity was low, whereby the average number of alleles per locus (A) was 3.3 and observed (H 0 ) and expected heterozygosities (H e ) were 0.336 and 0.298, respectively. The average fixation index was significantly higher than zero (F = 0.112), suggesting inbreeding. Significant SGS was found up to 7 m and between 31 to 38 m, indicating that trees growing within these distances may be related. Estimates of the effective population size indicated that the 100 sampled trees correspond to 14 individuals that are neither related nor inbred. Our results suggest that the microsatellite markers developed in this study are suitable for studies on genetic diversity and structure, mating systems, gene flow and SGS in this species.

GENETIC DIVERSITY AND MATING SYSTEM OF Rhizophora mangle L. (RHIZOPHORACEAE) IN NORTHERN BRAZIL REVEALED BY MICROSATELLITE ANALYSIS

“…The number of alleles obtained in this study was lower than that obtained by Pil et al (2011) for the same species from the Brazilian coast, although those authors used a different set of loci and number of individuals across 10 populations. We observed an average heterozygosity of 0.454 and an average expected heterozygosity of 0.372 for adult trees (Table 1), and these results were similar to those of other studies (Forti et al, 2014;Kennedy et al, 2017). Forti.…”

Understanding genetic diversity, spatial genetic structure, and mating system through microsatellite markers for the conservation and sustainable use of Acrocomia aculeata (Jacq.) Lodd. Ex Mart.

“…The low linkage disequilibrium (3.48%) concentrated in AM population likely does not reflect linkage between loci, but Forti et al (2014) and Tambarussi et al (2016) for tropical tree species. Therefore, we assume that the loci are not linked and are suitable for use in this study.…”

Gene flow and fine-scale spatial genetic structure inCabralea canjerana(Meliaceae), a common tree species from the Brazilian Atlantic forest

“…A strong SGS and low level of gene flow was found for populations of other Atlantic forest trees, such as Ocotea catharinensis (Tarazi et al 2010), Copaifera langsdorffii (Sebbenn et al 2011) and Esenbeckia leiocarpa (Forti et al 2014). Forest fragmentation was considered the main factor restricting the gene flow and promoting SGS amongst these populations.…”