Evolutionary Origins of Mammalian Coronaviruses Revealed

Core Concepts

The author argues that mammalian coronaviruses originated recently in bats and diversified through host switches, challenging previous notions of long-term codiversification with hosts.

Abstract

Recent research sheds light on the evolutionary history of mammalian coronaviruses. The study suggests a recent origin in bats and diversification through host switches, contradicting previous assumptions of long-term codiversification. The findings have implications for understanding future zoonotic risks and transmission patterns.
The study focused on the evolutionary origins and diversity hotspots of mammalian coronaviruses. By analyzing genetic data from 35 sOTUs associated with mammalian hosts, researchers uncovered insights into the history of these viruses. Results indicate a scenario of recent origination in bats and diversification by preferential host switches within mammalian orders.
Coronaviruses are found predominantly in mammals, particularly bats, suggesting a likely mammalian origin for these viruses. The timing of the Coronaviridae family's origination has been debated, with conflicting estimates ranging from thousands to millions of years ago. Previous studies have suggested codiversification between coronaviruses and their hosts over long periods, but this new research challenges those assumptions.
The study used phylogenetic analyses to reconstruct the evolutionary relationships between coronaviruses and their mammalian hosts. Results revealed a significant phylogenetic signal indicating that closely related coronaviruses tend to infect closely related mammals. This pattern suggests that diversification of Coronaviridae is linked to host evolutionary history through preferential host switches rather than long-term cospeciation events.
Furthermore, the analysis identified hotspots of coronavirus diversity concentrated in East Asia and Europe, with implications for future transmission scenarios. The findings highlight the potential for rapid spread and increased species diversity across different regions due to frequent host switches among mammals.
Overall, the study provides valuable insights into the evolutionary dynamics of mammalian coronaviruses, emphasizing recent origination in bats and diversification through host switches as key drivers shaping their genetic diversity and geographic distribution.

Stats

Woo et al found a recent origin around 10 thousand years ago.
Wertheim et al estimated an ancient origin around 293 million years ago.
Hayman & Knox obtained similar results using splitting times of hosts as constraints.
Mantel test: r=0.38; P=0.0001 for overall association between coronaviruses and mammals.
Phylogenetic distances: BEAST2 MCC tree used for analysis.
Ecological distances: UniFrac distances calculated based on interaction network matrix.
ALE reconciliations inferred average numbers: 145 cospeciations, 65 losses, 0 duplications, 92 host switches.
ALE found an origination within bats in 64% reconciliations.
eMPRess estimated significant reconciliations favoring recent origination in bats (54%).

Quotes

"Coronaviruses originated recently in bats and diversified through host switches."
"The high frequency of recombination makes coronavirus evolution especially dynamic."
"Results challenge previous notions of long-term virus-host codiversification."

Key Insights Distilled From

Recent evolutionary origin and localized diversity hotspots of mammalian coronaviruses

by Maestri,R., ... at www.biorxiv.org 03-09-2023

https://www.biorxiv.org/content/10.1101/2023.03.09.531875v2

Deeper Inquiries

What are the implications of recent coronavirus origins in bats for zoonotic risks

The implications of recent coronavirus origins in bats for zoonotic risks are significant. Bats have been identified as the likely origin of many coronaviruses, including SARS-CoV2, due to their high diversity and endemicity of these viruses. This suggests that bats serve as a reservoir for various coronaviruses, making them a potential source for future spillover events into other species, including humans. Understanding this recent origination in bats highlights the need for continued monitoring and research on bat populations to assess and mitigate zoonotic risks associated with coronaviruses.

How might conservation efforts targeting bat habitats help mitigate future coronavirus spillovers

Conservation efforts targeting bat habitats can play a crucial role in mitigating future coronavirus spillovers. By preserving natural habitats where bats reside undisturbed by human activities, conservationists can reduce the likelihood of human-bat interactions that may lead to virus transmission. Protecting bat habitats helps maintain biodiversity and ecosystem balance while minimizing disturbances that could trigger viral shedding or mutations in bat populations. Additionally, conserving bat habitats can limit opportunities for viruses to jump from bats to other wildlife or domestic animals before potentially infecting humans.

Could human activities driving contact between humans and wildlife contribute to future pandemics

Human activities driving contact between humans and wildlife significantly contribute to the risk of future pandemics. Encroachment into natural habitats through deforestation, urbanization, agriculture expansion, and hunting increases direct interactions between humans and wildlife species like bats carrying potential pathogens such as coronaviruses. These interactions create opportunities for cross-species transmission of viruses leading to new infectious diseases in humans (zoonoses). Therefore, sustainable land-use practices, habitat preservation initiatives focusing on reducing human-wildlife contact zones are essential strategies to minimize the chances of future pandemics originating from zoonotic sources like wild animals.