Barcoding utility in a mega-diverse, cross-continental genus: keeping pace with Cyrtodactylus geckos

Area of Science:

• Molecular Systematics
• Zoology
• Evolutionary Biology

Background:

• DNA barcoding, utilizing mitochondrial locus COI, is widely adopted in molecular systematics due to accessible primers and subsidized sequencing.
• The genus Cyrtodactylus, a diverse squamate group with complex biogeography, has many species described based on morphology alone, complicating phylogenetic understanding.
• Previous systematic investigations have not always assessed the specific utility of barcoding data for particular taxonomic groups.

Purpose of the Study:

• To evaluate the phylogenetic utility of DNA barcoding (COI gene) within the diverse gecko genus Cyrtodactylus.
• To highlight the need for inclusive molecular assessments by examining the geopolitical paraphyly in Vietnamese Cyrtodactylus.
• To compare the effectiveness of COI with the legacy marker ND2 for phylogenetic analysis.

Main Methods:

• Phylogenetic analysis using the mitochondrial COI gene.
• Comparison of COI marker performance against the ND2 marker.
• Case study analysis of Vietnamese Cyrtodactylus to illustrate biogeographic complexities.

Main Results:

• The COI gene demonstrates value as an interspecific marker for Cyrtodactylus, aiding in species-level identification.
• COI exhibits limitations at deeper evolutionary scales, suggesting it may not be sufficient for resolving ancient divergences.
• The study reveals a geopolitically paraphyletic history within Vietnamese Cyrtodactylus, underscoring the need for molecular data.

Conclusions:

• DNA barcoding (COI) is a valuable tool for interspecific resolution within the gecko genus Cyrtodactylus.
• The limitations of COI at deeper evolutionary scales necessitate the use of additional markers or methods for comprehensive phylogenies.
• Subsidized methods like Cold Code are crucial for integrating molecular data into species descriptions to ensure accurate phylogenetic understanding.