Karyotype and COI gene sequences of Chironomus melanotus Keyl, 1961 from the Yaroslavl region, Russia, and the difficulties with its identification using GenBank and BOLD systems

Abstract

Karyotype and COI gene sequences of Chironomus melanotus Keyl, 1961 from the Yaroslavl region (Russia) were analyzed. A low level of chromosomal polymorphism has been confirmed, eventually eight banding sequences were found: melA1, melB1, melC1, melD1, melE1, melF1, and melG1; only melD2 was found in two larvae from the Sunoga river. Analysis of phylogenetic tree and estimated genetic distances has shown not all COI gene sequences of Ch. melanotus in GenBank and BOLD to belong to this species. The lower distance of 0.4% was observed between two sequences from the Yaroslavl region and Finland, apparently these are true Ch. melanotus sequences. The distances between true Ch. melanotus and other sequences from Finland were 9.5% and 12.4%, and from Sweden it was 11%. The average genetic distance between studied sequences of 9.1% is out of the range of the 3% threshold previously determined for chironomids. According to our estimates, there are two sequences with a distance of 2.9% that may belong to Ch. annularius Meigen, 1818, and one sequence with a genetic distance of 2.1%, may belonging to Ch. cingulatus Meigen, 1830, which has been confirmed karyologically. Another two sequences form a separate cluster. We suggest that they either belong to a known species, but are not present in the databases, or belong to a distinct, undescribed species.

Karyotypes and COI Gene Sequences of Chironomus annularius Sensu Lato (Diptera, Chironomidae) from Russia, Mongolia, and Armenia

“…In addition, we used COI gene sequences of Ch. "annularius" from the GenBank and BOLD databases, realizing that there may be errors in species identification, as mentioned earlier [25,27].…”

“…The Chironomus species have giant polytene chromosomes with which we usually can accurately identify their species [7,12,23,24]. We already know that for the best results in identifying the species of chironomids, it is necessary to use a comprehensive approach that includes morphological, cytogenetic, and molecular genetic analyses [25][26][27].…”

The first record of Chironomus nuditarsis Keyl, 1961 from Sevan Lake (Armenia) confirmed by morphology, karyotype and COI gene sequence

“…Unfortunately, we did not have the opportunity to collect more samples of this species. We regularly suggest to use a comprehensive approach to the species identification of the genus Chironomus , which includes morphology, cytogenetics and molecular genetics ( Bolshakov and Movergoz 2022 ; Bolshakov et al 2022a , 2022b ). In this study, we have decided to use a single Chironomus larva to obtain a complex of scientific data.…”

“…However, the results of molecular genetic analysis further supported the suggestion that both species belong to the Ch. plumosus group ( Djomin 2011 ; Karmokov 2019 ; Bolshakov and Movergoz 2022 ; Bolshakov et al 2022a ) so both species are now considered members of the Ch. plumosus group.…”

Karyotypes and COI Gene Sequences of Chironomus sp. Le1 (Kiknadze and Salova, 1996), Ch. laetus (Belyanina and Filinkova, 1996) and Their Hybrid from the Yamal Peninsula, Arctic Zone of Russia

“…Previously, we found that the species name "Chironomus melanotus" matches several COI gene sequences, and the genetic p-distance between different populations varied from 0.4 to 12.4%, indicating that not all sequences belong to Ch. melanotus [11]. As we know, the genetic distance threshold is not suitable for all Chironomus species and depends on intra and interspecific sequence divergences; for the COI gene, it varies from 9 to 20% and, in rare cases, from 1 to 4% [12].…”