First finding of the separated eggs of Lophius litulon (Lophiiformes Lophiidae) by DNA-based identification from Korea in Northwest Pacific

Abstract

The separated pelagic eggs of Lophius litulon were first found by DNA-based identification. The eggs were sorted from the sample collected around the Gageo-rock in Yellow Sea from Korea. The morphology of eggs was described. For the verification of species identification, the 16SrDNA and COI genes of mitochondrial DNA were used as a molecular marker. The 16SrDNA sequences agreed with that of L. litulon (JQ178228) deposited in NCBI (http://www.ncbi.nlm.nih.gov/). However, the 16SrDNA phylogenetic tree by NJ method showed that there were suspicious sequences in the other species in the same genus, such as L. piscatorius, L. americanus, and L. budegassa. The COI gene was amplified with specific primer sets designed in this study referring to the sequences of adult specimens of L. litulon. The adult specimens were verified by morphology. The adult sequences had two haplotypes, A and B. They were same to those of L. litulon (haplotype A EU660720, JF952786/ haplotype B EU660703). The sequences of eggs were identical to the haplotype A. Eggs were identified as L. litulon. From the phylogenetic relationship of COI gene among Lophiidae, the COI gene showed that it was the adequate molecular marker for species identification of L. litulon as well as Lophiidae spp. Consequently, in order to make it clear to identify fish eggs into species level, it needs to consider the reliability of sequences deposited in database and the efation of species identification, the 16SrDNA and COI genes of mitochondrial DNA were used as a molecular marker. The 16SrDNA sequences agreed with that of L. litulon (JQ178228) deposited in NCBI (http://www.ncbi.nlm.nih.gov/). However, the 16SrDNA phylogenetic tree by NJ method showed that there were suspicious sequences in the other species in the same genus, such as L. piscatorius, L. americanus, and L. budegassa. The COI gene was amplified with specific primer sets designed in this study referring to the sequences of adult specimens of L. litulon. The adult specimens were verified by morphology. The adult sequences had two haplotypes, A and B. They were same to those of L. litulon (haplotype A EU660720, JF952786/ haplotype B EU660703). The sequences of eggs were identical to the haplotype A. Eggs were identified as L. litulon. From the phylogenetic relationship of COI gene among Lophiidae, the COI gene showed that it was the adequate molecular marker for species identification of L. litulon as well as Lophiidae spp. Consequently, in order to make it clear to identify fish eggs into species level, it needs to consider the reliability of sequences deposited in database and the ef