Structure and evolution of the Phasianidae mitochondrial DNA control region

Structure, evolution and phylogenetic informativeness of eelpouts (Cottoidei: Zoarcales) mitochondrial control region sequences

Control region (CR) is a major non-coding domain of mitochondrial DNA in vertebrates which contains the promoters for replication and transcription of mitochondrial genome along with the binding sites for metabolic machinery and, hence, is a vital element for the integrity of mitochondrial genome as a biological replicator. The origin and diversity of structural elements within CR have been intensively studied in recent years with the involvement of new diverse taxa. In this paper, we provide new data on the nucleotide and structural patterns of CR evolution and phylogenetic suitability among eelpouts (Cottoidei: Zoarcales). To achieve this, we carried out a comparative phylogenetic and structural analysis of 29 CR sequences belonging to the long shanny Stichaeus grigorjewi together with nine sequences of other eelpouts taxa representing four families in contrast to mitochondrial protein-coding fragments. The CR organization within S. grigorjewi, as well as in all other eelpouts, is consistent with the common three-domain structure known from most vertebrates. We found a hidden CR variation constrains on the landscape level and a lack of nucleotide saturation. Finally, our results demonstrate the advantage of the length variation in CR sequences for phylogenetic reconstructions among eelpouts.

Two mitochondrial genomes in Alcedinidae (Ceryle rudis/Halcyon pileata) and the phylogenetic placement of Coraciiformes

Coraciiformes comprises 209 species belonging to ten families with significant divergence on external morphologies and life styles. The phylogenetic placement of Coraciiformes was still in debate. Here, we determined the complete mitochondrial genomes (mitogenomes) of Crested Kingfisher (Ceryle rudis) and Black-capped Kingfisher (Halcyon pileata). The mitogenomes were 17,355 bp (C. rudis) and 17,612 bp (H. pileata) in length, and both of them contained 37 genes (two rRNA genes, 22 tRNA genes and 13 protein-coding genes) and one control region. The gene organizations and characters of two mitogenomes were similar with those of other mitogenomes in Coraciiformes, however the sizes and nucleotide composition of control regions in different mitogenomes were significantly different. Phylogenetic trees were constructed with both Bayesian and Maximum Likelihood methods based on mitogenome sequences from 11 families of six orders. The trees based on two different data sets supported the basal position of Psittacidae (Psittaciformes), the closest relationship between Cuculiformes (Cuculidae) and Trogoniformes (Trogonidae), and the close relationship between Coraciiformes and Piciformes. The phylogenetic placement of the clade including Cuculiformes and Trogoniformes has not been resolved in present study, which need further investigations with more molecular markers and species. The mitogenome sequences presented here provided valuable data for further taxonomic studies on Coraciiformes and other related groups.

Structure and variation of the Fringillidae (Aves: Passeriformes) mitochondrial DNA control region and their phylogenetic relationship

The control region is the major noncoding segment of animal mitochondrial DNA. To infer the structure and variation of Fringillidae mitochondrial DNA control region, the entire control region sequences of 25 species were analyzed. The length of the control region sequences was very conserved (1230 ± 18) and can be separated into three domains. The frequency of both substitutions and gaps was highest in the third domain and lowest in the central region. The control region has the same flanking gene order from tRNA^Glu to tRNA^Phe. Genetic distances between species ranged from 1.80% (between Carduelis pinus and Carduelis spinus) to 25.34% (between Carduelis sinica and Coccothraustes vespertinus). The average genetic distances among the species within the genera varied from 5.11% (Leucosticte) to 14.31% (Carpodacus). The average genetic distances showed insignificantly negative correlation with ts/tv. Domain III is the most variable of the three domains among all the genera. The control region of Fringillidae contains a putative TAS element and the highly conserved CSB-1, and F, E, D, C boxes. However, neither CSB-2 nor CSB-3 could be unambiguously identified in the Fringillidae. The maximum likelihood method was used to construct a phylogenetic tree. Control region analysis demonstrated that some currently recognized genera may be polyphyletic, including Carpodacus, Carduelis and Serinus.

Structure and variation of the Anseriformes mitochondrial DNA control region

The control region is the major non-coding segment of animal mitochondrial DNA. To infer the structure and variation of Anseriformes mitochondrial DNA control region, the control region sequences of 52 species were analyzed. The length of the control region sequences ranged from 968 bp (Chenonetta jubata) to 1335 bp (Anseranas semipalmata) and can be separated into three domains. There is a deletion of 100-130 bp in Anatinae, compared to other groups of Anserinae. The average genetic distances among the species within the genera varied from 4.14% (Anser) to 10.58% (Cygnus). The average genetic distances showed insignificantly negative correlation with ts/tv. Domain I is the most variable among the three domains among all the genera. Five conserved sequence boxes in the domain II of Anseriformes sequences were identified. The alignment of the Anseriformes five boxes sequences showed considerable sequence variation. CSB-1, -2 and 3 were not found in the Anseriformes. Maximum-likelihood method was used to construct a phylogenetic tree, which grouped all of the genera into four divergent clades. Anseranas + Chauna and Dendrocygna were identified as early offshoots of the Anatidae. All the remaining taxa fell into two clades that correspond to the two subfamilies Anserinae and Anatiane.