Topic 1 : A freak DNA change 25 million years ago is why humans lack tails
Introduction
One of the most striking anatomical features of apes, which sets them apart from monkeys, is the absence of a tail. All mammals have a tail at some point during their development, but apes, including humans, chimpanzees, bonobos, gorillas, orangutans, and gibbons, lose them in utero, leaving behind three to five vestigial vertebrae called the coccyx, or tailbone.
The compact genome
- Every cell of an organism contains a full copy of that organism’s DNA, called the genome. The genome contains the information that the cell uses to make proteins, the workhorses of the cell.
- Each protein is coded by a specific section of the genome, called the gene.
- Not all cells make all the proteins encoded in the genome. For instance, pancreatic cells make insulin, but skin cells don’t. Skin cells make other proteins, such as keratin, that the pancreas cells don’t.
- A cell achieves this selective protein production by first making a temporary copy of the gene, called the mRNA, that then drives protein production.
- So pancreas cells will first copy information in the insulin gene into insulin mRNA, and the insulin mRNA will be used to make insulin protein. Skin cells follow the same process to make keratin.
‘Junk’ DNA
- Bacteria keep their genomes very compact while more complex life forms don’t.
- In the bacterial genome, the genes are arranged in tandem: where one gene ends, another begins. As a result, genes make up 85–90% of the bacterial genome.
- But in complex organisms, genes are spaced far apart. In humans, for example, only 1.5% of the genome codes for proteins. At the time, scientists didn’t know what the rest did and called it ‘junk’ DNA.
- Today we know this ‘junk’ DNA is responsible for various functions, including controlling when to make a protein and when not to.
- A significant fraction of the ‘junk’ also contains transposable elements. These are pieces of DNA that can shift their positions within the genome.
- One such element, called Alu, is unique to primates (both apes and monkeys). It is tiny, being made up of around 300 base pairs (the human genome is approximately 3 billion base pairs).
- Normally, in nearly all cell types, these elements copy themselves, switch to different locations, and insert themselves into the genome again with minimal consequence to health or evolution. This is because the insertion event is unique to a given cell.
The Alu accident
- Twenty-five million years ago, after the ape and monkey lineages separated, a chance insertion of an Alu element occurred in an important gene in the zygote of an ancient creature and it caused that ancient creature to not develop a tail.
- And because the insertion had happened in the zygote, it was imprinted in the DNA of every cell of that creature, and its subsequent offspring — all of them. That creature was the ancestor of all modern apes.
- It was eventually found hiding in the ‘junk’ DNA.
A tailoring defect
- A peculiar feature of the genome of complex animals is that a gene never exists as one continuous piece in the genome.
- The gene is divided into segments separated by ‘junk’; it’s stitched together only when the cell makes the mRNA.
- This strategy has multiple advantages. For example, the pieces can be rearranged differently at the time of stitching to make different proteins from the same DNA code.
- The research found the Alu insertion between two pieces of a gene called TBXT — a gene already known as one of many involved in tail formation in monkeys.
- The team realised this insertion was present in all apes and absent in all other monkeys — a strong sign that it’s the cause of tail loss in apes.
Conclusion
Tail loss has been implicated in bipedalism: our ability to walk on two legs. But it is difficult to speculate on exactly what evolutionary benefit was conferred on the ancestral tailless ape that led to its selection by nature. Whatever that selection pressure may have been, what is incredible is how evolution seized upon that one-in-a-million event and used it to create an ape that would go on to rule the world.
Topic 2 : Indian aviation, a case of air safety at a discount
Context
The oft-repeated statements by the Union Minister for Civil Aviation, Jyotiraditya Scindia, and the Directorate General of Civil Aviation (DGCA), that, first, ‘safety is paramount’ and, second, ‘India has one of the fastest growing aviation sectors’, are ones that are at complete variance with each other when there are two very serious safety issues staring at aviation in India.
Aviation safety
- Aviation safety involves a combination of pre-flight planning, operational procedures, maintenance protocols, and continuous oversight to prevent accidents and incidents.
- Safety is a core value-offering of rapid and dependable air services, and international cooperation on aviation safety by governments and industry groups, through the International Civil Aviation Organization (ICAO), has helped to make commercial aircraft the safest way to travel
Regulatory Framework
- International Civil Aviation Organization (ICAO sets global standards for aviation safety, security, efficiency, and environmental protection.
- Each country has its aviation regulatory body responsible for enforcing safety regulations and standards.
- Aircraft are designed, manufactured and undergo extensive training to meet rigorous safety standards set by aviation authorities.
- Pilots undergo rigorous training to obtain and maintain their licenses, including simulation exercises for emergency scenarios.
- Crew Resource Management (CRM) focuses on effective communication and decision-making among the flight crew to enhance overall safety.
- Advanced radar and satellite technologies help monitor aircraft movements and prevent collisions.
- Advanced avionics systems enhance navigation, communication, and aircraft monitoring.
- Technologies like Traffic Collision Avoidance Systems (TCAS) help prevent mid-air collisions.
- Data from flight data recorders (black boxes) and other sources contribute to improving aviation safety through lessons learned.
- Regulations and policies address crew fatigue to minimize its impact on performance.
Aviation safety in India
- Directorate General of Civil Aviation (DGCA), under the Ministry of Civil Aviation, is the regulatory body responsible for overseeing civil aviation activities, including safety, licensing, and airworthiness in India
- In 2023, India’s aviation safety oversight ranking jumped to 55th position from 112th place, with a significant improvement in the country’s score under the ICAO’s coordinated validation mission.
- The aviation safety regulator of the U.S., the Federal Aviation Administration (FAA), had retained the “Category 1” status for India’s aviation safety oversight following a review in early 2023.
- The countries listed under ‘Category-1’ meet the ICAO standards for safety oversight of civil aviation.
Aviation safety crucial for the economic growth of a country
- Facilitates Business and Trade.
- Boosts Tourism Industry.
- Encourages Foreign Direct Investment (FDI).
- Supports Export Industries.
- Stimulates Job Creation.
- Contributes to GDP Growth.
- Promotes Regional Development.
- Attracts High-Value Industries.
- Catalyzes Infrastructure Development.
Way forward
- Directorate General of Civil Aviation (DGCA) has made significant changes in the regulations pertaining to Flight Duty Time Limitations (FDTL) for flight crew, in line with the international best practices.
- DGCA further envisages to the adoption of a new regime of fatigue management i.e. Fatigue Risk Management System (FRMS) going forward.
- The revised FDTL regulation is a stepping stone towards FRMS implementation in India. FRMS is a data-driven approach to enhance monitoring and reporting of flight crew fatigue.
- With the implementation of the revised FDTL regulations, the aviation sector aspires for safer skies.