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

Abstract

The study of the biological diversity of the Arctic zone yields intriguing results. Initial research on the lakes of the Yamal Peninsula resulted in the identification of Chironomus laetus and the hybrid Ch. laetus x Ch. sp. Le1. To avoid misidentification, we used morphological, cytogenetic, and molecular genetic approaches. By cytogenetics, in Ch. sp. Le1, seven banding sequences were found: Le1A1, Le1B1, Le1C1, Le1D1, Le1E1, Le1F1, and Le1G1. The karyotype of Ch. laetus was mapped for the first time; it is the first species with the arm combinations AE BC DF G. We propose the name of a new cytocomplex—“laetus”. DNA-barcoding of the COI gene was carried out for Ch. laetus and Ch. laetus x Ch. sp. Le1 for the first time. The estimated genetic distance between the sequences of Ch. laetus and Ch. riihimakiensis is 2.3–2.5%. The high similarity in morphology, banding sequences, and the possibility of hybridization indicate a close relationship between Ch. laetus and Ch. sp. Le1, which is assumed to be the northern variant of Ch. riihimakiensis. Molecular genetic data suggests the presence of a subgroup with Ch. laetus.

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

“…Another explanation is interspecific hybridization and horizontal transfer of mitochondrial genes with fixation in one of the initial species in a population ( Guryev and Blinov 2002 ; Polukonova et al 2009 ; Karmokov 2019 ; Bolshakov et al 2021 ). Previously, we confirmed the existence of hybrids even between species from different cytocomplexes ( Bolshakov et al 2022b ).…”

“…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.…”

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

“…Perhaps the length of 535 bp is insufficient for an accurate identification of the sequence of C. bernensis (JN016851), or it could be a result of interspecific hybridization and horizontal transfer of mitochondrial genes, with fixation in one of the parental species in the population [37,54,55]. We have already shown that hybridization of species from different cytocomplexes is possible [56]. Sample C. muratensis (KC250748) from Sweden may also be misidentified.…”