Population variability in Chironomus (Camptochironomus) species (Diptera, Nematocera) with a Holarctic distribution: evidence of mitochondrial gene flow

Abstract

Phylogenetic analysis of DNA sequences from mitochondrial (mt) genes (Cytochrome b and Cytochrome oxidase I) and one nuclear gene (globin 2b) was used for the investigation of Nearctic and Palearctic populations representing four Chironomus species of the subgenus Camptochironomus, namely C. biwaprimus, C. pallidivittatus, C. tentans sensu stricto and C. dilutus (the last two species constitute Holarctic C. tentans sensu lato). Phenograms constructed on the basis of mt sequences were not congruent with trees based on nuclear genes, or with morphological and cytological data. The mt tree divided the populations by continental region, rather than by the species groupings recognized by the other data sets. The incongruence is explained by mt gene flow resulting from hybridization between the sympatric species on each continent. Calculation of divergence times, based on the sequence data, suggest that C. tentans (s.l.) and C. pallidivittatus have both been in North America for about 2.5 My.

DNA barcoding supports reclassification of JapaneseChironomusspecies (Diptera: Chironomidae)

“…For the Chironomidae, there is a growing number of studies of DNA barcoding and phylogenetic analysis using DNA sequences (Guryev et al 2001;Martin et al 2002Martin et al , 2007Ekrem et al 2007Ekrem et al , 2010aPfenninger et al 2007;Sinclair & Gresens 2008;Polukonova et al 2009;Krosch et al 2011;Stur & Ekrem 2011;Cranston et al 2012;Kim et al 2012;Roongruangwongse et al 2012;Anderson et al 2013;Proulx et al 2013;Lin et al 2015) and attempts at aquatic biomonitoring using DNA sequences (Sharley et al 2004;Carew et al 2007Carew et al , 2011Brodin et al 2013). In these studies, the commonly used sequences were of the mitochondrial genes cytochromec oxidase subunit I (COI) and cytochromeb oxidase (cytb) and the nuclear genes globin 2β (gb2β), rudimentary (CAD) and ribosomal RNA (18S and 28S rRNA).…”

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“…As in previous chironomid studies (Guryev et al 2001;Martin et al 2002), calibration of the molecular clock for Cytb sequences was performed using the time of the estimated split of the species Chironomus thummi and C. tentans (60 my), obtained using the substitution rate of invertebrate globin genes (Kao et al 1994) and comparison to slowly evolving Drosophila genes (Chen et al 1995). This converts to an mt sequence divergence rate of 0.75% (corrected distance) per my (Martin et al 2002). This figure can be used here since the test statistic, namely the relative difference between a rate-constrained model and a model that has no constraints on branch length (likelihood ratio test of Felsenstein 1981), failed to reject overall rate homogeneity (value less than 0.01).…”

“…The amount of divergence between the sequences can be used to estimate the separation times of the populations. As in previous chironomid studies (Guryev et al 2001;Martin et al 2002), calibration of the molecular clock for Cytb sequences was performed using the time of the estimated split of the species Chironomus thummi and C. tentans (60 my), obtained using the substitution rate of invertebrate globin genes (Kao et al 1994) and comparison to slowly evolving Drosophila genes (Chen et al 1995). This converts to an mt sequence divergence rate of 0.75% (corrected distance) per my (Martin et al 2002).…”

Preliminary Study of Phylogenetic Relationship of Rice Field Chironomidae (Diptera) Inferred From DNA Sequences of Mitochondrial Cytochrome Oxidase Subunit I

“…The systematics, phylogenetics and taxonomic studies of insects have however developed quickly with the emergence of molecular techniques. These techniques provide an effective tool toward more accurate identification of ambiguous chironomid species [11][12][13][14][15][16] . In most molecular studies the mitochondrial DNA (mtDNA) is used and often only one or several genes can act as an effective marker such as cytochrome Oxidase Subunit one (COI).…”

“…Perhaps, the most intensive study of Chironomus was the study on species identification and distribution in the Holarctic region [13] . DNA sequences from the mitochondrial Cytochrome b and cytochrome oxidase subunit I genes and a nuclear gene (globin 2b) were investigated in this study.…”