How A Virus Evolves
FRONTLINE|May 22, 2020
The mutations of SARS-CoV-2, according to a new study, have led to the emergence of a dominant virus type, Type A2a, distinctly different from the original virus, Type O, that emerged from Wuhan, and spreading with much higher frequencies than the original version.
R. Ramachandran
How A Virus Evolves

Viruses readily mutate. There is nothing surprising about this because it is their nature to do so. This happens due to the imperfect copying mechanism at work as viruses replicate in the cells of infected hosts.

The complete set of genetic information needed to sustain an organism, such as the virus, is its genome, which, in the case of viruses, can be made up either of the DNA or the RNA molecule. The DNA and the RNA can be thought of as a string of (genetic) letters, and a genome can be imagined to be long stretches of these letters with different parts of it encoding for different proteins required for the organism’s existence. Mutations are just random errors that occur during the process of copying these letters during viral multiplication and such errors accumulate during every replicating cycle, which can occur within hours or even less. RNA viruses mutate faster than DNA viruses because their replication mechanism is intrinsically more error-prone. Likewise single-stranded viruses mutate more often than double-stranded ones.

Viruses cannot exist in isolation; they need a host to replicate and survive. Mutations generate a diversity of virus population in a single infected host. This amazing ability of viruses to mutate is what drives their evolutionary change. Most mutations may be inconsequential. But mutations that adversely affect some virus function or the other, which impede its sustenance, will get removed by natural selection. If during an outbreak, a mutated virus with a greater (or lesser) degree of infectivity or virulence were to appear in a population, it does not immediately follow that the mutation will sustain and continue to spread with high frequency, unless it gives the virus a selective advantage as instances during the current COVID-19 pandemic that we consider below illustrate.

This story is from the May 22, 2020 edition of FRONTLINE.

Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.

This story is from the May 22, 2020 edition of FRONTLINE.

Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 8,500+ magazines and newspapers.

MORE STORIES FROM FRONTLINEView All
How Not To Handle An Epidemic
FRONTLINE

How Not To Handle An Epidemic

The lockdowns were meant to buy time to put in place appropriate health measures and contain the coronavirus’ spread, but they have failed to achieve the objective and heaped immense misery on the marginalised sections of society. India is still in the exponential phase of the COVID-19 infection and community transmission is a reality that the government refuses to accept.

time-read
9 mins  |
June 5, 2020
Tragedy on foot
FRONTLINE

Tragedy on foot

As the COVID-19-induced lockdown cuts the ground beneath their feet in Tamil Nadu, thousands of migrant workers are trudging along the highway to the relative safety of their upcountry homes.

time-read
10+ mins  |
June 5, 2020
Sarpanchs as game changers
FRONTLINE

Sarpanchs as game changers

Odisha manages to keep COVID-19 well under control because of the strong participation of panchayati raj institutions and the community at the grass-roots level under the leadership of Chief Minister Naveen Patnaik.

time-read
7 mins  |
June 5, 2020
Scapegoating China
FRONTLINE

Scapegoating China

As the COVID-19 death rate spikes and the economy tanks in the United States, Donald Trump and his advisers target China and the World Health Organisation with an eye to winning the forthcoming presidential election.

time-read
10 mins  |
June 5, 2020
New worries
FRONTLINE

New worries

Kerala’s measured approach to the pandemic and lockdown has yielded results. But it still has to grapple with their huge economic impact on its economy, which it feels the Centre’s special financial relief package does little to alleviate.

time-read
9 mins  |
June 5, 2020
FRONTLINE

No love lost for labour

Taking advantage of the lockdown and the inability of workers to organise protests, many State governments introduce sweeping changes to labour laws to the detriment of workers on the pretext of reviving production and boosting the economy.

time-read
8 mins  |
June 5, 2020
Capital's Malthusian moment
FRONTLINE

Capital's Malthusian moment

In a world that needs substantial reorienting of production and distribution, Indian capital is resorting to a militant form of moribund neoliberalism to overcome its current crisis. In this pursuit of profit, it is ready and willing to throw into mortal peril millions whom it adjudicates as not worth their means—an admixture of social Darwinism born of capital’s avarice and brutalism spawned by Hindutva. .

time-read
10+ mins  |
June 5, 2020
Understanding migration
FRONTLINE

Understanding migration

When governments and their plans are found to be blatantly wanting in addressing reverse migration, exercises such as the Ekta Parishad’s survey of migrant workers throughout India can be useful to work out creative long-lasting solutions.

time-read
10 mins  |
June 5, 2020
Waiting for Jabalpur moment
FRONTLINE

Waiting for Jabalpur moment

The Supreme Court’s role in ensuring executive accountability during the ongoing lockdown leaves much to be desired. Standing in shining contrast is the record of some High Courts.

time-read
10+ mins  |
June 5, 2020
An empty package
FRONTLINE

An empty package

The Modi regime, which has been unable to control the COVID-19 infection, restore economic activity and provide relief to millions exposed to starvation, trains its sights on Indian democracy, making use of the panic generated by fear and a lockdown that forecloses paths of resistance.

time-read
10+ mins  |
June 5, 2020