Reconstruction of the diapsid ancestral genome permits chromosome evolution tracing in avian and non-avian dinosaurs

O'Connor, R E; Romanov, M N; Kiazim, L G; Barrett, P M; Farre Belmonte, M; Damas, J; Ferguson-Smith, M; Valenzuela, N; Larkin, D M; Griffin, D K

Abstract

Genomic organisation of extinct lineages can be inferred from extant chromosome-level genome assemblies. Here, we apply bioinformatic and molecular cytogenetic approaches to determine the genomic structure of the diapsid common ancestor. We then infer the events that likely occurred along this lineage from theropod dinosaurs through to modern birds. Our results suggest that most elements of a typical ‘avian-like’ karyotype (40 chromosome pairs, including 30 microchromosomes) were in place before the divergence of turtles from birds ~255 mya. This genome organisation therefore predates the emergence of early dinosaurs and pterosaurs and the evolution of flight. Remaining largely unchanged interchromosomally through the dinosaur–theropod route that led to modern birds, intrachromosomal changes nonetheless reveal evolutionary breakpoint regions enriched for genes with ontology terms related to chromatin organisation and transcription. This genomic structure therefore appears highly stable yet contributes to a large degree of phenotypic diversity, as well as underpinning adaptive responses to major environmental disruptions via intrachromosomal repatterning.

Citation

O'Connor, R. E., Romanov, M. N., Kiazim, L. G., Barrett, P. M., Farre Belmonte, M., Damas, J., …Griffin, D. K. (2018). Reconstruction of the diapsid ancestral genome permits chromosome evolution tracing in avian and non-avian dinosaurs. Nature Communications, 9(1), 1883. https://doi.org/10.1038/s41467-018-04267-9

• Journal Article Type: Article
• Acceptance Date: Apr 12, 2018
• Publication Date: May 21, 2018
• Deposit Date: Jun 4, 2018
• Publicly Available Date: Nov 21, 2020
• Journal: Nature Communications
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 1
• Pages: 1883
• DOI: https://doi.org/10.1038/s41467-018-04267-9
• Public URL: https://rvc-repository.worktribe.com/output/1387188