PUNCTUATED EQUILIBRIUM AND CORONA VIRUS

PUNCTUATED EQUILIBRIUM AND CORONA VIRUS

In 1972 stephan J Gould and Niles Eldredge two Harvard Paleantologists took the scientific world by storm witheir papers on challenging the core assumption of Darwins theory of evolution. It lanched the careers of most influential biologists of our time, perhaps the best known since Darwin. Punctuated equilibrium holds that the great majority of species originate in geologial moments (PUNCTUATIONS) and persists in STASIS parellel to the x axis in the diagram. This idea has become the the foundation of a new view of hierarchial selection and macroevolution. Punctuated equilibrium represents much broader paradigm about the nature of change. Indeed we hunans may now be living within a punctuation. This thesis is what I want to apply in corona virus evolution. For those who are new to the word Paleontology- It is the study od ancient fossilized plants and animals. Study of Dinosars  comes under Paleontology. Paleantology has two branches Paleozoology and paleobotany. My wife  Anandi had paleozoology for her Masters programme  and I had Paleobotany for my Masters progamme.

Punctuated equibrium refutes incrementalism a theory according to which species  evolve slowly by means of successve mutations. In figure shown here the the green spiked spot is the place of appearance of sudden nutants (PUNCTUATION) after a very long dull period parallel to the X AXIS shown here as time. This is the typical characteristic of PUNCTUATED EQUILIBRIUM. The green spiked circles labelled as crtical events in the figure are the PUNCTUATIONS.

Human and plant viruses had their own way of naming and classifying as and when they were discovered.  There was no organized systematic way to classify viruses.

Nobel laureate David Baltimore, Robert A.Miilikan of CALTECH developed a system for classifying viruses based in part on their genetic material or genome. Incidentally David Baltimore received his Nobel Prize in 1975 for

BALTIMORE SYSTEM OF CLASSIFICATION OF VIRUSES

discovering the enzyme REVERSE TRANSCRIPATASE found in AIDS virus. The discovery of reverse transcriptase put an end to Cricks central dogma theory that order comes only from Nuclear DNA. Baltimore’s classification system. divides viruses into SEVEN GROUPS. SARS VIRUS (SEVERE ACUTE RESPIRATORY SYNDROME CORONA VIRUS 2). It causes deadly disease. It is in the IV group and it is single stranded positive RNA which makes messenger RNA directly to virus proteins which results in the fast spread of covid 19 in the human body (SEE BALTIMORE CLASSIFICATIO DIAGRAM ABOVE). Baltimore took the messenger RNA as central target point for the classification of viruses.

Covid 19 virus is a member of corona virus family called PICORNAVIRIDAE. When viewed under electron microscope corona viruses have a crown like appearance (corona is the Latin word for crown). The spiky protein that covers the virus on the outer edge of virus particle allow it to bind to receptors on host cells leading to infection. THERE IS NOW SEVEN CORONA VIRUSES known to infect humans.

It is assumed that SARS Cove 2 spread from animals to humans possibly through the Huan seafood and wild life market in Wuhan province. At the start of the pandemic bats were identified as a likely source of the virus. They harbour a range of SARS like viruses and theoretically could have transmitted COV19 directly to humans. But the viruses so far identified in bats have different characteristics from SARS-CoV-2 2. One important difference is spike protein which helps the virus gain entry to and infect human cells, compared with viruses found in bats, the protein of SARS Covid 2 sticks better to a receptor protein ACE2 found on the surface of many human cells, meaning thereby that it has got higher change of entering them. To infect our cells covid 19 spike protein turns the key on the molecular door way formed by our ACE2 proteins. Mutations that adapted its spike protein to humanACE2 helped the virus make its way out of bats, where SARS related corona viruses have circulated for thousands of years, and eventually trggered the COVID 19 related pandemic. THIS IS THE PUNCTUATION OF STEPEN GOULD AND NILES ELDRIGES WHICH IS ALSO DEPICTED AS CRTICAL STAGE IN FIGURE 1. After the smaller SARS epidemic in the early 2000s, COVID 19 is the second viral out break  driven by a corona virus that acquired the key to our cells.

CORONA VIRUS’ DISTANT PAST REVEALS THEIR ANCIENT CHARACTERS THAT COULD HELP THEM JUMP SPECIES.

SARS RELATED CORONA VIRUSES WITH THEIR SPILLOVER POTENTIAL IS MORE WIDE SPREAD THAN PREVIOUSLY THOUGHT.

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 The ACE2 enzyme- the full name is ANGIOTENSIN CONVERTING ENZYME 2 (ACE2). It is founf in all parts of human body like lungs heart kidney big and small intestines. The covid 19 enters human body via ACE2 receptor ACE 2enzyme is found in the membrane lining the nose and mouth also.

To enter the human cells the SARS-COV 2 spike protein uses human ACE2 as an entry receptor. Hence the interaction between the SARS-COV- 2 S and ACE 2 is critical for the fusion and thereby the transmission and pathogenicity of the virus. (REFER DIAGRAMS 2 AND 3)

Under the Baltimore suystem of classification of viruses corona virus come under GROUP IV. Viruses of this group have SINGLE STRANDED RNA (SSRNA) as their genome with a positive polarity. POSITIVE POLARITY means that the genomic RNA OF COVID 19 CAN SERVE DIRECTLY AS MESSENGER RNA TO TRANSLATE INTO VIRUS PROTEIN THROUGH RIBOSOMES.

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When we are in the critical stage (punctuated stage) as shown  in the figure1 corona virus also reaches the punctuated stage and enters the human cells.Refer diagrams 2 and 3.

DIAGRAM 2

 DIAGRAM 3

 To make the long story short we human species and  our fellow traveller COVID 19 are in PUNCTUATED EQUILIBRIUM and have many hundred more years of togetherness.

The latest news tells us that a new bronchial disease called the WALKING PNEUMONIA is sweeping across china where thousands of cildren are admitted into hospitals every day presumably caused by a mycoplasma. This could be another episode of PUNCTUATED EQUILIBRIUM in the offing

Professor K.A.Balasubramanian

Ph.D.(IARI-NEW DELHI), Ph.D.(IMPERIAL COLLEGE LONDON) D.I.C.(IMPERIAL COLLEGE LONDON)

AUSTIN, TEXAS, USA