Complete mitochondrial genome of Chroicocephalus brunnicephalus from India: phylogeny with other Larids

Abstract

The complete mitogenome sequence of the brown-headed gull, Chroicocephalus brunnicephalus was determined in this study. The 16,771 bp genome consists of 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, and 22 transfer RNA (tRNA) genes, and a control region (CR). The decoded mitogenome was AT-rich (54.77%) with nine overlapping and 17 intergenic spacer regions. Most of the PCGs were started by a typical ATG initiation codon except for cox1 and nad3. Further, the usual termination codons (AGG, TAG, TAA, and AGA) were used by 11 PCGs except for cox3 and nad4. The concatenated PCGs based Bayesian phylogeny clearly discriminates all the Laridae species and reflects the sister relationship of C. brunnicephalus with C. ridibundus. The present mitogenome-based phylogeny was congruent with the earlier hypothesis and confirmed the evolutionary position of the brown-headed gull as masked species. The generated mitogenome of C. brunnicephalus is almost identical to the previously generated mitogenome from China except for two base pairs in CR. To visualize the population structure of this migratory species, we propose more sampling from different geographical locations and the generation of additional molecular data to clarify the reality.

Keywords: Gulls; evolution; migratory species; mitogenome; phylogeny.

Figure 1.

(A) Map showing the collection locality of C. brunnicephalus from the southern coast of India. (B) The spherical representation of mitochondrial genome of C. brunnicephalus. Direction of gene transcription is indicated by arrows. PCGs are shown as blue arrows, rRNA genes as coral arrows, tRNA genes as orchid arrows, and non-coding control region as mint rectangle. The GC-skew is plotted using green and violet color sliding window as the deviation from the average in the complete mitogenome. The species photograph was taken by the third author (G.M.) (C) The BA phylogeny based on the concatenated nucleotide sequences of 13 PCGs showing the evolutionary relationship of the studied taxa with other Laridae species. The posterior probability support values were superimposed with each node. The figure was edited with the representative species photograph acquired from the internet using Adobe Photoshop CS version 8.0.