The molecular evolution of genes previously associated with large sizes reveals possible pathways to cetacean gigantism

Author(s)

Silva, Felipe Andre ; Souza, Erica M. S. ; Ramos, Elisa ; Freitas, Lucas ; Nery, Mariana F. F.

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 13, n. 1, p. 10-pg., 2023-01-19.

Abstract

Cetaceans are a group of aquatic mammals with the largest body sizes among living animals, including giant representatives such as blue and fin whales. To understand the genetic bases of gigantism in cetaceans, we performed molecular evolutionary analyses on five genes (GHSR, IGF2, IGFBP2, IGFBP7, and EGF) from the growth hormone/insulin-like growth factor axis, and four genes (ZFAT, EGF, LCORL, and PLAG1) previously described as related to the size of species evolutionarily close to cetaceans, such as pigs, cows, and sheep. Our dataset comprised 19 species of cetaceans, seven of which are classified as giants because they exceed 10 m in length. Our results revealed signs of positive selection in genes from the growth hormone/insulin-like growth factor axis and also in those related to body increase in cetacean-related species. In addition, pseudogenization of the EGF gene was detected in the lineage of toothless cetaceans, Mysticeti. Our results suggest the action of positive selection on gigantism in genes that act both in body augmentation and in mitigating its consequences, such as cancer suppression when involved in processes such as division, migration, and cell development control. (AU)

• FAPESP's process: 15/18269-1 - Using comparative genomics to understand convergent evolution of mammals: tracking the molecular footprints of the marine and riverine environment colonisation
• Grantee: Mariana Freitas Nery
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 17/25058-2 - Adaptive convergent evolution of hematophagy-related genes in Insecta
• Grantee: Lucas Araujo Freitas
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/01236-1 - Evolution of new environments colonization in mammals: investigating the molecular footprints of fluvial environment colonization and the osmoregulation system
• Grantee: Elisa Karen da Silva Ramos
• Support Opportunities: Scholarships in Brazil - Doctorate