Molecular characterization of the nearly complete nuclear ribosomal DNA sequence of the Neotropical freshwater copepod Arctodiaptomus dorsalis (Marsh, 1907) (Copepoda, Calanoida, Diaptomidae)

Abstract

Arctodiaptomus dorsalis has been reported in the Philippines as an invasive species, which originated from Central America. Apart from its wide distribution in the United States and Central America, it is now widely distributed in many lakes in the Philippine islands, such as Luzon Island and southwestern Mindanao, making it an ideal specimen for studies on population dynamics and population genetics. Recently, new techniques have been emerging as important zooplankton monitoring tools, such as metabarcoding and the use of environmental DNA/environmental RNA. However, these would only be useful if good-quality reference DNA sequences are available before utilizing these techniques. This study sequenced the nearly complete nuclear ribosomal DNA (nrDNA) of A. dorsalis from 202 individuals from Lake Taal, Batangas. The total length was 5887 bp, which includes the partial 18S sequences, and the complete 5.8S, ITS and 28S sequences with an organization that is typical for any eukaryotic organism. This is the first record of a nearly complete nrDNA sequence for freshwater calanoid copepods and is considered an important stepping stone for further molecular studies in freshwater Copepoda.