Published paper: Improving mosquito barcoding

I have had the fortune to be involved in a study on the quality of reference material for mosquito barcoding for biodiversity studies. The study, which was led by Maurício Moraes Zenker at the Universidade Federal de São Carlos in Brazil, looked at the availability of public data for mosquitoes in online databases for two widely used DNA barcoding markers in Culicidae: the COI and ITS2 regions (1). Last week, this study was published in Scientific Reports.

The paper shows that around 30% of known species were covered for the COI gene in BOLD  and  GenBank, and 12% of species for ITS2 in GenBank. The Afrotropical, Australian and Oriental biogeographic regions had the lowest coverages, while the Nearctic, Palearctic and Oceanian regions had the highest. Countries with a higher diversity of mosquitoes tended to have lower coverage, which was surprisingly also the case for countries with higher numbers of medically important species. At the same time, countries with a higher number of endemic species tended to have a higher species coverage in the databases.

With this study, we would like to advocate for better curatorship of voucher specimens representing sequences in the databases. Also, an integrative taxonomic approach that combines various genetic markers with morphological analyses is important to allow a better use of DNA barcoding and metabarcoding in a diverse array of applications, including vector species detection and biodiversity monitoring.

Importantly, this work underscores how reliant DNA barcoding is on proper taxonomic foundations, including morphological characterisations. Molecular identification of species cannot happen in a vacuum! I would like to extend a big thanks for Maurício who invited me to take part in this study and who have done an excellent job putting it all together!

Reference

• Moraes Zenker M, Pineda Portella T, Costa Pessoa FA, Bengtsson-Palme J, Galetti PM: Low coverage of species constrains the use of DNA barcoding to assess mosquito biodiversity. Scientific Reports, 14, 7432 (2024). doi: 10.1038/s41598-024-58071-1 [Paper link]