Environmental Variation Influences Genome Evolution in Hispaniolan Trunk Anoles (Anolis distichus)

Area of Science:

• Evolutionary Biology
• Genomics
• Ecology

Background:

• Environmental variation is a key driver of evolutionary processes, including population differentiation, local adaptation, and speciation.
• The North Caribbean bark anole (Anolis distichus) displays significant phenotypic diversity across Hispaniola's varied habitats.

Purpose of the Study:

• To investigate the role of environmental variation in the genome-wide evolution and local adaptation of Anolis distichus.
• To determine the relative contributions of environmental variation versus geographic distance to population differentiation.

Main Methods:

• Genome-scale double-digest restriction-associated DNA sequencing (ddRADseq) was performed on nearly 200 Anolis distichus individuals.
• Geographic Information System (GIS) data layers representing environmental variables were integrated with genomic data.
• Genotype-environment association (GEA) methods were employed to identify loci under local adaptation.

Main Results:

• Hispaniola's mountain ranges significantly influence genome-wide divergence and migration patterns.
• Environmental variation explains more range-wide genomic differentiation than geographic distance alone.
• While hundreds of loci correlated with environmental variables, fewer than 100 were consistently identified across methods, and only 10 showed parallel adaptation in regional subsets, indicating infrequent parallel evolution.

Conclusions:

• Abiotic environmental variation is a critical factor shaping the evolution and diversity of Anolis distichus across Hispaniola.
• Geographic barriers and environmental heterogeneity contribute to population structure and divergence.
• The study highlights the complex interplay between environment, geography, and adaptation in shaping species evolution.