Unravelling the genetic differentiation among varieties of the Neotropical savanna tree Hancornia speciosa Gomes
Nenhuma Miniatura disponível
Data
2018
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
• Background and Aims Spatial distribution of species genetic diversity is often driven by geographical distance
(isolation by distance) or environmental conditions (isolation by environment), especially under climate change
scenarios such as Quaternary glaciations. Here, we used coalescent analyses coupled with ecological niche modelling
(ENM), spatially explicit quantile regression analyses and the multiple matrix regression with randomization
(MMRR) approach to unravel the patterns of genetic differentiation in the widely distributed Neotropical savanna
tree, Hancornia speciosa (Apocynaceae). Due to its high morphological differentiation, the species was originally
classified into six botanical varieties by Monachino, and has recently been recognized as only two varieties by Flora
do Brasil 2020. Thus, H. speciosa is a good biological model for learning about evolution of phenotypic plasticity
under genetic and ecological effects, and predicting their responses to changing environmental conditions.
• Methods We sampled 28 populations (777 individuals) of Monachino’s four varieties of H. speciosa and used
seven microsatellite loci to genotype them.
• Key Results Bayesian clustering showed five distinct genetic groups (K = 5) with high admixture among
Monachino’s varieties, mainly among populations in the central area of the species geographical range. Genetic
differentiation among Monachino’s varieties was lower than the genetic differentiation among populations
within varieties, with higher within-population inbreeding. A high historical connectivity among populations of
the central Cerrado shown by coalescent analyses may explain the high admixture among varieties. In addition,
areas of higher climatic suitability also presented higher genetic diversity in such a way that the wide historical
refugium across central Brazil might have promoted the long-term connectivity among populations. Yet, FST was
significantly related to geographic distances, but not to environmental distances, and coalescent analyses and
ENM predicted a demographical scenario of quasi-stability through time.
• Conclusions Our findings show that demographical history and isolation by distance, but not isolation by
environment, drove genetic differentiation of populations. Finally, the genetic clusters do not support the two
recently recognized botanical varieties of H. speciosa, but partially support Monachino’s classification at least for
the four sampled varieties, similar to morphological variation.
Descrição
Palavras-chave
Apocynaceae, Quantile regression, Bayesian clustering, Cerrado, Coalescence, Ecological niche modelling, Hierarchical AMOVA, Isolation by distance, Isolation by nvironment, Microsatellites, Multiple matrix regression with randomization
Citação
COLLEVATTI, Rosane G.; RODRIGUES, Eduardo E.; VITORINO, Luciana C.; LIMA-RIBEIRO, Matheus S.; CHAVES, Lázaro J.; TELLES, Mariana P. C. Unravelling the genetic differentiation among varieties of the Neotropical savanna tree Hancornia speciosa Gomes. Annals of Botany, Oxford, v. 122. n. 6, p. 973–984, 2018. DOI: 10.1093/aob/mcy060. Disponível em: https://www-ncbi-nlm-nih.ez49.periodicos.capes.gov.br/pmc/issues/324898/. Acesso em: 26 jan. 2023.