The first whole genome and transcriptome of the cinereous vulture reveals adaptation in the gastric and immune defense systems and possible convergent evolution between the Old and New World vultures

Background: The cinereous vulture, Aegypius monachus, is the largest bird of prey and plays a key role in the ecosystem by removing carcasses, thus preventing the spread of diseases. Its feeding habits force it to cope with constant exposure to pathogens, making this species an interesting target for discovering functionally selected genetic variants. Furthermore, the presence of two independently evolved vulture groups, Old World and New World vultures, provides a natural experiment in which to investigate convergent evolution due to obligate scavenging. Results: We sequenced the genome of a cinereous vulture, and mapped it to the bald eagle reference genome, a close relative with a divergence time of 18 million years. By comparing the cinereous vulture to other avian genomes, we find positively selected genetic variations in this species associated with respiration, likely linked to their ability of immune defense responses and gastric acid secretion, consistent with their ability to digest carcasses. Comparisons between the Old World and New World vulture groups suggest convergent gene evolution. We assemble the cinereous vulture blood transcriptome from a second individual, and annotate genes. Finally, we infer the demographic history of the cinereous vulture which shows marked fluctuations in effective population size during the late Pleistocene. Conclusions: We present the first genome and transcriptome analyses of the cinereous vulture compared to other avian genomes and transcriptomes, revealing genetic signatures of dietary and environmental adaptations accompanied by possible convergent evolution between the Old World and New World vulturesopen

The first whole genome and transcriptome of the cinereous vulture reveals adaptation in the gastric and immune defense systems and possible convergent evolution between the Old and New World vultures

Abstract Background: The cinereous vulture, Aegypius monachus, is the largest bird of prey and plays a key role in the ecosystem by removing carcasses, thus preventing the spread of diseases. Its feeding habits force it to cope with constant exposure to pathogens, making this species an interesting target for discovering functionally selected genetic variants. Furthermore, the presence of two independently evolved vulture groups, Old World and New World vultures, provides a natural experiment in which to investigate convergent evolution due to obligate scavenging. Results: We sequenced the genome of a cinereous vulture, and mapped it to the bald eagle reference genome, a close relative with a divergence time of 18 million years. By comparing the cinereous vulture to other avian genomes, we find positively selected genetic variations in this species associated with respiration, likely linked to their ability of immune defense responses and gastric acid secretion, consistent with their ability to digest carcasses. Comparisons between the Old World and New World vulture groups suggest convergent gene evolution. We assemble the cinereous vulture blood transcriptome from a second individual, and annotate genes. Finally, we infer the demographic history of the cinereous vulture which shows marked fluctuations in effective population size during the late Pleistocene. Conclusions: We present the first genome and transcriptome analyses of the cinereous vulture compared to other avian genomes and transcriptomes, revealing genetic signatures of dietary and environmental adaptations accompanied by possible convergent evolution between the Old World and New World vultures

Additional file 2: Fig. S1. of The first whole genome and transcriptome of the cinereous vulture reveals adaptation in the gastric and immune defense systems and possible convergent evolution between the Old and New World vultures

Estimation of genome size using 17-mers. Fig. S2 The divergence time of avian species. Fig. S3 Specific amino acid changes in the gastric acid secretion associated genes. Fig. S4 Species distribution of BLASTx top hits of cinereous vulture transcripts. Fig. S5 NR protein database properties for the assembled unigenes. Fig. S6 Gene Ontology classifications of cinereous vulture unigenes. Fig. S7 Amino-acid sequence comparison of toll-like receptor 1 of the Griffon and cinereous vultures. (DOCX 2228 kb

Additional file 1: Table S1. of The first whole genome and transcriptome of the cinereous vulture reveals adaptation in the gastric and immune defense systems and possible convergent evolution between the Old and New World vultures

Sequencing and analysis statistics of the cinereous vulture’s WGS relative to the bald eagle genome. Table S2 17-mer statistics. Table S3 Summary of SNVs and small indel in the cinereous vulture. Table S4 PSGs list of the Accipitrimorphae using a branch-site model. Table S5 PSGs list of the Accipitrimorphae using a branch model. Table S6 Functional annotation chart of PSGs of the Accipitrimorphae. Table S7 PSGs list of the cinereous vulture using a branch-site model. Table S8 PSGs list of the cinereous vulture using a branch model. Table S9 PSGs list of the turkey vulture using a branch-site model. Table S10 PSGs list of the turkey vulture using a branch model. Table S11 Functional annotation chart of PSGs of the cinereous vulture. Table S12 Functional annotation chart of PSGs of the turkey vulture. Table S13 Unique amino acid changes of the turkey vulture. Table S14 Unique amino acid changes of the cinereous vulture Table S15 Unique amino acid changes of the Accipitridae. Table S16 Unique amino acid changes on sites between Accipitridae and Cathartidae of the digestive system-related proteins. Table S17 Unique amino acid changes on sites between Accipitridae and Cathartidae of the gastric acid secretion-related proteins. Table S18 Statistics regarding whole-transcriptome sequences and unigene construction. Table S19 GO analysis for the blood transcriptome of the cinereous vulture. Table S20 KEGG pathway analysis for the blood transcriptome of the cinereous vulture. Table S21 Gene expression in the cinereous vulture compared to the other avian species. Table S22 Immune related genes expression in the cinereous vulture compared to the other avian species. (XLSX 635 kb