Resident ID proponents I wont name to protect their brittle egoes are again implying that the study of evolution by “evolutionary theorists” has no practical application in stuff like medical research.
This reflects a common view out there among creationists (gleefully fabricated and regurgitated by many ID propagandizers) that evolution is this entirely imaginary field where evolutionary biologists just dream up histories for life that never occurred in reality.
A frequent example is that inferring evolutionary histories (phylogenetic trees) from data is basically just like arbitrarily drawing lines on paper between things and then telling those dreaded “just so stories”. Disregarding the hypocricy of such an accusation (because ID-creationism is one giant just-so story) I think we would do well to ask if that is actually true?
Well there’s a new review article out in the Journal of Molecular Evolution on one of my favorite topics. That’s right, it’s a Ancestral Sequence Reconstruction again:
Abstract
As both a computational and an experimental endeavor, ancestral sequence reconstruction remains a timely and important technique. Modern approaches to conduct ancestral sequence reconstruction for proteins are built upon a conceptual framework from journal founder Emile Zuckerkandl. On top of this, work on maximum likelihood phylogenetics published in Journal of Molecular Evolution in 1996 was one of the first approaches for generating maximum likelihood ancestral sequences of proteins. From its computational history, future model development needs as well as potential applications in areas as diverse as computational systems biology, molecular community ecology, infectious disease therapeutics and other biomedical applications, and biotechnology are discussed. From its past in this journal, there is a bright future for ancestral sequence reconstruction in the field of evolutionary biology.
Ancestral Sequence Reconstruction and Infectious Disease
Ancestral sequence reconstruction can be used to understand viral evolution and towards therapeutic applications (Arenas 2020). An understanding of the evolutionary histories of these viruses can lead to applications in detecting targeted regions for future therapeutics, and to assist in predicting new viral resistance against current drugs.
Ancestral sequence reconstruction is also of emerging interest for vaccine technologies, especially for the development of vaccines to combat rapidly evolving viruses such as HIV and influenza strains (Gaschen et al. 2002; Ducatez et al. 2011). Using ancestrally derived sequences to create vaccine reagents takes advantage of the evolutionary history of the virus. This strategy contrasts with other methods which construct a consensus sequence from different viral strains, ignoring phylogenetic structure. A vaccine reagent can be based on the last common ancestral sequence of all the strains that are circulating, or from other points in the tree. For example, when the phylogenetic topology is skewed, the “center of tree” method may be implemented. The center of tree method considers the ancestral sequence that minimizes the evolutionary distance between different viral strains of interest (Nickle et al. 2003).
In the age of the SARS-CoV-2, ancestral sequence reconstruction has become of immediate interest to assist in vaccine development (Zhou et al. 2020). Like the rapidly evolving RNA virus influenza and retrovirus HIV, SARS-CoV-2 is also an RNA virus. However, a recent study used ancestral sequence reconstruction to demonstrate that unlike other RNA viruses, mutations in SARS-CoV-2 are rare, as the evolution rate is slower than the transmission rate. Because of the slow evolution of SARS-CoV-2, only one vaccine candidate may be necessary to match all currently circulating SARS-CoV-2 variants (Dearlove et al. 2020).
Aside from disease causing viruses, viruses are also developed to serve as a vehicle for gene therapy (Ivics et al. 1997). The Adeno-associated Virus (AAV) has been considered an efficient gene therapy for both inherited and infectious diseases. However, the complex structure and diversity associated with different target receptor binding for AAV make the virus difficult to properly structurally assemble when designed. Using ancestral sequence reconstruction, Zinn et al. (2015) were able to provide a virus with a structure that would remain evolutionarily resilient to future mutations and maintain broad clinical applicability.
Biomedical and Biotechnological Directions for Ancient Proteins
In addition to all the insights ASR reveals about natural evolutionary processes, it turns out that ancient proteins also have applied functions in biotechnology and biomedicine (Randall et al. 2016). Ancestral variants have been used to develop clinical treatments for type 2 diabetes (Skovgaard et al. 2006), gout (Kratzer et al. 2014), hemophilia (Zakas et al. 2017), tyrosinemia (Hendrikse et al. 2020) and others. It is anticipated that this trend in biomedicine will continue as ASR generates proteins having expanded biomolecular functionalities with lower immunogenic responses in human patients compared to their modern protein counterparts. Further, ancestral variants are being used in the biotechnology sector due to their unique and desirable properties. Companies such as nanoGUNE (Manteca et al. 2017), Syngenta, New England Biolabs (Zhou et al. 2012), DuPont (Ladics et al. 2020) and others have developed or integrated ancient proteins into their biotechnology product development pipelines, while some ancient proteins have even been tested for their value in the cosmetic industry (Perez-Jimenez et al. 2011).
The irony of ancient proteins having an applied utility to the development of therapeutics and industrial enzymes is clear. It is reasonable to expect that this utility will expand within the public and private sectors as more examples are discovered in the coming years. Sometimes one must explore the past in order to navigate the future.
