Admixture may be extensive among hyperdominant Amazon rainforest tree species.

Area of Science:

• Ecology
• Evolutionary Biology
• Genetics
• Botany

Background:

• Admixture, a process where species acquire novel alleles, is a potential driver of plant diversity.
• The role of admixture in tropical plant diversity, particularly in long-lived species, remains poorly understood.
• The Parvifolia clade of Eschweilera (Lecythidaceae) comprises widespread and abundant Amazonian tree species, making it an ideal system to study admixture.

Purpose of the Study:

• To investigate the occurrence and impact of admixture within the ecologically significant Parvifolia clade of Eschweilera.
• To determine if hybridization has contributed to the evolution of widespread and variable Amazonian tree species.
• To assess whether admixture has led to the erosion of genetic or morphological species identities within this clade.

Main Methods:

• Conducted a detailed phylogenomic investigation using target capture sequencing.
• Analyzed 33 species within the Parvifolia clade of Eschweilera.
• Examined specific hypotheses of admixture within a robust phylogenetic framework.

Main Results:

• Strong evidence of admixture was found among three dominant species: Eschweilera coriacea, E. wachenheimii, and E. parviflora.
• No significant evidence of admixture was detected among other lineages within the clade.
• Accepted species and geographic structures within species remained largely distinguishable, indicating limited erosion of identities.

Conclusions:

• Hybridization plays a role in the evolutionary diversification of some of the most widespread and ecologically variable Amazonian tree species.
• Admixture in Eschweilera has not resulted in the widespread loss of genetic or morphological distinctiveness among species.
• Current morphological-based species delimitations are effective for characterizing the lineage diversity of the Eschweilera Parvifolia clade.