Putative Local Adaptive SNPs in the Genus Avicennia

Area of Science:

• Botany
• Genetics
• Ecology

Background:

• The Avicennia genus, comprising eight species, thrives in intertidal zones across tropical and temperate regions globally.
• These mangroves possess significant medicinal value and have diverse geographical distributions from West Asia to Latin America.
• While genetic and phylogenetic studies exist, none have specifically addressed the geographical adaptation of single nucleotide polymorphisms (SNPs) in Avicennia.

Purpose of the Study:

• To identify discriminating single nucleotide polymorphisms (SNPs) within the Avicennia genus.
• To investigate the association between these SNPs and geographical variables.
• To understand the geographical adaptation of Avicennia mangroves at a genetic level.

Main Methods:

• Utilized Internal Transcribed Spacer (ITS) sequences from approximately 120 Avicennia taxa worldwide.
• Employed computational analyses, including multivariate and Bayesian approaches (CCA, RDA, LFMM), to identify adaptive SNPs.
• Visualized genetic changes and adaptation patterns using Manhattan and skyline plots.

Main Results:

• Identified numerous SNPs significantly associated with geographical and ecological variables, as indicated by Manhattan plots.
• Revealed genetic changes linked to local and geographical adaptation through skyline plots.
• Demonstrated that genetic changes in Avicennia did not follow a molecular clock model, suggesting positive selection.

Conclusions:

• Single nucleotide polymorphisms (SNPs) in Avicennia are strongly associated with geographical adaptation.
• Avicennia mangroves exhibit genetic adaptations driven by positive selection pressures in response to diverse geographical environments.
• This research provides novel insights into the evolutionary mechanisms underlying mangrove distribution and adaptation.