Complete mitogenome of the critically endangered Asian king vulture (Sarcogyps calvus) (Aves, Accipitriformes, Accipitridae): evolutionary insights and comparative analysis

The Asian king vulture (<i>Sarcogypscalvus</i>), also known as the red-headed vulture, is an Old World vulture (Gypini) facing severe population declines. This study aimed to assemble the complete mitogenome of <i>S.calvus</i>, explore its phylogenetic relationships, estimate divergence times, and examine genetic distances and amino acid substitutions. The mitogenome was de novo assembled from genomic DNA extracted from the blood of a female <i>S.calvus</i>. Phylogenetic and pairwise genetic distance analyses were conducted, comparing <i>S.calvus</i> with other members of Gypini, New World vultures (Cathartidae) and various other birds. The assembled mitogenome was 17,750 base pairs in length, comprising 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes and two control regions. Most PCGs used the ATG start codon, except for cytochrome c oxidase subunit 1 (<i>COX1</i>), which employed GTG. Phylogenetic analysis revealed a close genetic relationship between <i>S.calvus</i> and other members of Gypini, with an estimated divergence time of 16.7 million years ago. Genetic distance analysis indicated that <i>S.calvus</i> was more closely related to other Gypini, as well as to <i>Spilornischeela</i> and <i>Circaetuspectoralis</i> (Circaetini)), than to Cathartidae. Conserved amino acid substitutions between Gypini and Cathartidae were primarily observed in the NADH-ubiquinone oxidoreductase chain 1 (<i>ND1</i>) gene. This study provided the first complete mitogenome of <i>S.calvus</i>, offering new insights into its genomic structure, evolutionary history, and genetic relationships.