Daily Quiz: UPSC Prelims Marathon (Science & Technology ) – July 23, 2020

Genetic drift can have major effects when a population is sharply reduced in size by a natural disaster (bottleneck effect) or when a small group splits off from the main population to found a colony (founder effect).

• The founder effect is another extreme example of drift, one that occurs when a small group of individuals breaks off from a larger population to establish a colony.
• The new colony is isolated from the original population, and the founding individuals may not represent the full genetic diversity of the original population.
• That is, alleles in the founding population may be present at different frequencies than in the original population, and some alleles may be missing altogether.
• The founder effect is similar in concept to the bottleneck effect, but it occurs via a different mechanism (colonization rather than catastrophe).
• Genetic studies done on the people of the Lakshwadeep archipelago by a team, led by K. Thangaraj at CSIR-Centre for Cellular and Molecular Biology (CCMB), for the first time have shown that a majority of human ancestry in Lakshadweep is largely derived from South Asia with minor influences from East and West Eurasia.
• And, there was no evidence of early human migration through the Lakshadweep islands.
• “We found a strong founder effect for both paternal and maternal lineages — a sign that the island population had limited genetic mixing”, said by scientists.

The United Nations announced 2019 as the International Year of the Periodic Table of the Chemical Elements to highlight its first publication in 1869.

• The periodic table as we know it today was first designed by the Russian scientist Dmitri Ivanovich Mendeleev.
• This year marks the 150th anniversary of the first publication of the periodic table by Mendeleev.
• Since its creation, the periodic table has been at the centre of a lot of vivid debates and is now considered as “one of the most important and influential achievements in modern science reflecting the essence not only of chemistry, but also of physics, biology and other disciplines.”
• Mendeleev’s genius lies in the acknowledgement that at the time, not all the elements were known yet, so he left gaps in the table for undiscovered elements.
• At that time, only 63 elements had been identified. Still the properties of five other elements (the gaps brilliantly added to complete the table) could already been determined using the table.

Bats serves as natural hosts for numerous viruses including Ebola virus, Nipah virus, corona viruses such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) and the 2019 novel corona virus that has infected nearly 10,000 people and killed over 200 others.

• Even as these viruses cause harm in humans, they rarely if at all cause any harmful effects in bats. This is the case even when the viral load is extremely high in bats.
• The reason why bats can harbour these viruses without getting affected is simply because bats can avoid excessive virus-induced inflammation, which often causes severe diseases in animals and people infected with viruses.
• The researchers found that significantly reduced inflammation in bats was because activation of an important protein — NLRP3 — that recognises both cellular stress and viral/bacterial infections was significantly dampened in bat immune cells.
• Studying further, the researchers found that reduced activation of the NLRP3 protein was in turn due to impaired production of mRNA (transcript).
• Since mRNA production is impaired the NLRP3 protein production gets compromised leading to less amount of the protein being produced.
• But this was not the case with mice and humans — there was no impairment to mRNA production so the NLRP3 protein was unaffected.

The traces pesticides leave in treated products or those left by veterinary drugs in animals are called “residues”.

• The traces pesticides leave in treated products or those left by veterinary drugs in animals are called “residues”.
• A study of fruits and vegetables grown in the Nilgiris has found that some of the produce might be harbouring high levels of pesticide, beyond what is considered advisable. This was mainly true of potato and carrot.
• While the Food Safety and Standards Authority of India (FSSAI) prescribes a maximum residual level (MRL) for some of the organophosphate pesticides used, it does not prescribe it for some other pesticides used in the cultivation of fruit and vegetables.

A new snake eel species residing in the Bay of Bengal has been discovered and documented this month (January) by the Estuarine Biology Regional Centre (EBRC) of the Zoological Survey of India (ZSI) at Gopalpur-on-sea in Odisha.

• This new marine species has been named Ophichthus kailashchandrai to honour the vast contributions of Dr. Kailash Chandra, Director of ZSI, to Indian animal taxonomy.
• Ophichthus kailashchandrai is the eighth species of the Ophichthus genus found on the Indian coast. It is the fifth new species discovered by the Gopalpur ZSI in the last two years.
• The eel family ‘Ophichthidae’ comprises two sub-families — Myrophinae (69 species) and Ophichthinae (276 species).
• The sub-family Ophichthinae is identified by its hard tail and other osteological (bone) features, and it has 17 genera and 24 species.
• Out of them, seven species from the Ophichthus genus were earlier identified in Indian waters. The recent discovery is the eighth species of this genus.
• The Ophichthus kailashchandrai lives at a depth of around 50 metres in the sea. According to the studied specimens, individuals of this species are around 420 mm to 462 mm in length.
• They are light brown in colour, with white fins. They have a well-developed pectoral fin and also have a dorsal fin.
• Their posterior nostril is a hole covered by a flap on the upper lip opening towards the mouth.
• There are 180-182 total vertebrae in this new species. Their teeth are moderately elongated, conical and sharp.

Simultaneously removing heavy metals such as arsenic, chromium, cadmium and mercury from waste water with very high efficiency now appears possible, thanks to the work of researchers at the Indian Institute of Technology (IIT) Bombay.

• The carbon-based nanostructure that the team fabricated shows 80-90% adsorption efficiency for all the four heavy metals studied.
• No electricity is required for the nanostructure to remove heavy metals from water as it allows for gravity-driven purification of the water.
• The nanostructures can be recycled and reused multiple times.
• While there is an initial drop of about 8% after the first cycle, the efficiency remains constant at 75-85% in the subsequent cycles.
• The carbon nanostructure is able to adsorb the heavy metals in the wide range of pH conditions — pH 2 to 13.

In a Rapid Communication published on January 14 – 2020, the World Health Organization (WHO) had mentioned that the India-made Truenat MTB, a molecular diagnostic test to diagnose pulmonary and extrapulmonary TB and rifampicin-resistant TB, has high diagnostic accuracy.

• Truenat MTB has “high diagnostic accuracy as initial test to diagnose TB and to sequentially detect rifampicin resistance”, says the WHO Communication.
• Truenat MTB will be used as an initial test to diagnose TB thus replacing sputum smear microscopy.
• Truenat is developed by the Goa-based Molbio Diagnostics.
• The company was provided with technical assistance and resources by the Foundation for Innovative New Diagnostics (FIND) to help commercialize Truenat. Indian Council of Medical Research (ICMR) had assessed and validated the diagnostic tool.

A meteorite that crashed into rural southeastern Australia in a fireball in 1969 contained the oldest material ever found on Earth, stardust that predated the formation of our solar system by billions of years, scientists said on January 13 – 2020.

• The oldest of 40 tiny dust grains trapped inside the meteorite fragments retrieved around the town of Murchison in Victoria state dated from about 7 billion years ago, about 2.5 billion years before the sun, Earth and rest of our solar system formed, the researchers said.
• Scientists previously had found a pre-solar grain in the Murchison meteorite that was about 5.5 billion years old, until now the oldest-known solid material on Earth.
• The oldest-known minerals that formed on Earth are found in rock from Australia’s Jack Hills that formed 4.4 billion years ago, 100 million years after the planet formed.

Neglected tropical diseases (NTDs) – a diverse group of communicable diseases that prevail in tropical and subtropical conditions in 149 countries – affect more than one billion people and cost developing economies billions of dollars every year.

Populations living in poverty, without adequate sanitation and in close contact with infectious vectors and domestic animals and livestock are those worst affected.

As of 2017, the World Health Organization categorizes the following communicable diseases as neglected tropical diseases (NTDs):

• Buruli Ulcer
• Chagas Disease
• Chromoblastomycosisexternal icon
• Cysticercosis
• Dengue Fever
• Dracunculiasis (Guinea Worm Disease)
• Echinococcosis
• Fascioliasis
• Human African Trypanosomiasis (African Sleeping Sickness)
• Leishmaniasis
• Leprosy (Hansen’s Disease)
• Lymphatic Filariasis
• Mycetoma
• Onchocerciasis
• Rabies
• Schistosomiasis
• Soil-transmitted Helminths (STH) (Ascaris, Hookworm, and Whipworm)
• Trachoma
• Yawsexternal icon

While conventional sodium sulphur batteries require very high temperature (300 degree C) for operation, researchers at the Indian Institute of technology (IIT) Madras have designed a new sodium sulphur battery that can be operated at room temperature.

By operating the battery at room temperature, the team was able to achieve higher charge storage capacity (technically called the specific capacity) and nearly zero self-discharge when the battery is not being used.