Using DNA barcoding and phylogenetics to identify Antarctic invertebrate larvae: Lessons from a large scale study.

Area of Science:

• Marine biology
• Molecular ecology
• Antarctic research

Background:

• Accurate taxonomic identification of marine planktonic larvae is crucial for ecological studies.
• Advancements in genetic databases and DNA sequencing costs facilitate molecular identification methods.
• Previous studies often excluded early developmental stages like embryos.

Purpose of the Study:

• To develop and implement a practical molecular approach for identifying marine invertebrate larvae and embryos.
• To assess the feasibility of large-scale larval identification using molecular techniques.
• To provide guidelines for future molecular identification studies of marine larvae.

Main Methods:

• Collected over 2000 marine invertebrate larvae and embryos from the Ross Sea, Antarctica (2002-2007).
• Employed morphological identification to Phyla Mollusca, Echinodermata, Nemertea, and Annelida (Polychaeta).
• Utilized molecular methods including DNA sequencing of multiple loci, BLAST analysis, phylogenetic reconstruction, and MOTU validation.

Main Results:

• Successfully identified approximately 700 individuals to 53 Molecular Operational Taxonomic Units (MOTUs).
• This study is among the first to simultaneously identify both embryos and larvae using molecular techniques.
• Identified procedural challenges in larval collection, DNA amplification, contamination, and MOTU assignment.

Conclusions:

• A combined morphological and molecular approach provides reliable taxonomic identification of marine larvae.
• The developed molecular strategy is practical for large-scale studies and aids in understanding larval diversity.
• Procedural guidelines are provided to assist researchers in conducting future molecular identification studies of marine larvae.