Understanding Evolution Through the Lens of COVID-19

Darwin made two very important discoveries. First, descent with modification which is the pattern of evolution. Descent with modification makes five important predictions; (1) species change through time, (2) lineages split and diverge, (3) novel forms derive from earlier forms, (4) species are connected by descent from common ancestors - they are not independent, and finally (5) both the earth and life are old. The first three predictions are microevolution, speciation, and macroevolution respectively. Darwin had believed that evolution was rather slow, however, we now know that evolution actually occurs rapidly. 

Microorganisms such as bacteria and viruses undergo rapid evolution. We are in the middle of a pandemic caused by the novel coronavirus known as SARS-CoV-2 since late 2019. The coronaviruses are named for their crown-like spikes on their surface. Coronaviruses that infect animals can evolve to new human coronaviruses. SARS-CoV-3 happens to be one that evolved from an animal coronavirus. This proves macroevolution - that novel forms derive from earlier forms. The other two were SARS-CoV, the beta coronavirus that causes severe acute respiratory syndrome (SARS), and MERS-CoV, also a beta coronavirus that causes Middle East Respiratory Syndrome (MERS). [1]

Multiple variants of the SARS-CoV-2 have emerged. Scientists are closely monitoring the changes to the spikes on the surface of the virus through genetic analyses. Three variants have been identified. The United Kingdom (UK) identified B.1.1.7, a variant with many mutations. In South Africa, another variant emerged independently of B.1.1.7, labeled as B.1.351. Lastly, in Brazil, variant P.1 emerged, its mutations suggest that it may affect its ability to be recognized by antibodies. Public Health officials are researching to understand if these variants are detected by current viral tests, if they respond to medicines currently being used to treat COVID-19, and if it will change the effectiveness of the COVID-19 vaccines. This proves microevolution, covid-19 has evolved within the last year. [2]

A study published by Li et. al. details the evolution of SARS-CoV-2 by utilizing the matrix representation with parsimony (MRP) pseudo-sequence supertree analysis. Their research showed that the bat coronavirus RaTG13 is not the last common ancestor of SARS-CoV-2. However, they are connected by descent from a common ancestor, Darwin's fourth prediction. 

MRP pseudo-sequence supertree for SARS-CoV-2. Claudes of MERS-CoV, SARS-CoV, and SARS-CoV-2 are highlighted and labeled. This demonstrates speciation. [3]

SARS-CoV-2 sub-clades common mutation sites similarity coded as the clades in the phylogenetic tree above [3]

By looking closer to the evolution of COVID-19, it goes to show that evolution is not only theory but also a fact by demonstrating the predictions of descent with modification - microevolution, speciation, macroevolution, and that species are connected by a common ancestor. 

Works Cited: 

[1] "Coronavirus." Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 15 Feb. 2020, https://www.cdc.gov/coronavirus/types.html 

[2] "New Variants of the Virus That Causes COVID-19". Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 15 Feb. 2020, https://www.cdc.gov/coronavirus/2019-ncov/transmission/variant.html 

[3] Li, T., Liu, D., Yang, Y. et al. Phylogenetic supertree reveals detailed evolution of SARS-CoV-2. Sci Rep 10, 22366 (2020). https://doi-org.er.lib.k-state.edu/10.1038/s41598-020-79484-8