Daily Current Affairs

What our ancestors genomes can tell us about modern health (GS Paper 3, Science and Technology)

Context:

• Ancient DNA (aDNA) studies powered by cutting-edge genomic techniques have opened a window into the past, providing unprecedented insights into the genetic makeup of our ancestors.
• And by extracting and analysing DNA from ancient skeletal remains, scientists can reconstruct the genetic profiles of these people.

 

Details:

• Studies of such ancestral DNA have provided glimpses into the genetic diversity and population dynamics of ancient communities, their migration patterns, interactions, and adaptations to local environments, and even into the diseases these people confronted and how the afflictions shaped human evolution.
• For example, genomic technologies have given researchers a way to understand pathogens that spread in the distant past, and trace their origins and evolutionary trajectories.
• By reconstructing the genomes of these lifeforms, they have been able to piece together the emergence, spread, and adaptation of infectious diseases throughout human history.

 

Ancestral DNA and health:

• In a number of recent papers, researchers have also reported being able to use sequences of aDNA to understand genetic diseases that may have affected ancient humans, and through that open windows onto the medicines and tools that early human communities used.
• For example, some of the more common genetic diseases are the result of chromosomal abnormalities. Many chromosomal abnormalities result in chromosome number changes – that is, extra copies or deletions of entire chromosomes resulting in different clinical syndromes.
• For example Down’s syndrome is caused by an extra chromosome 21; Klinefelter’s syndrome due to an extra X chromosome; and Turner syndrome by the loss of one of the two X chromosomes in women.

 

Chromosomal karyotyping:

• Chromosomal karyotyping is a method to visualise the complete set of chromosomes in a cell, and is among the best techniques to diagnose such abnormalities. However, karyotyping requires live cells, which in turn requires scientists to adopt laborious methods to culture and stain them.
• The scientists today can fortunately use whole-genome sequencing data from fragmented and/or degraded DNA to understand chromosomal abnormalities. Scientists have since adopted these approaches to study chromosomal abnormalities in aDNA as well.
• For example, recently researchers at the Francis Crick Institute in London published evidence of some of the earliest known instances of Turner syndrome, Kinefelter’s syndrome, and Down’s syndrome in aDNA dating from the Iron age in Britain.
• Similarly, a research group from Italy, Germany, and the U.S. reported an interesting analysis of genetic variants associated with cardiovascular diseases in modern humans.
• They studied DNA isolated from 22 mummified individuals from a variety of geographical regions and time periods. Some 17 samples from ancient Egypt were dated to 3600 BC whereas those from Bolivia, Peru, Switzerland, and Australia were from 1500-1900 AD.
• In all, the scientists said they believe cardiovascular disease has been widespread in human populations for at least 5,000 years.

 

Linking ancestral DNA to diets:

• Insights into the lifestyles of ancient humans can also be gleaned from their genetic remains. One such material is pitch from the birch tree. There is some evidence that ancient humans extensively used birch pitch to repair stone tools and possibly fix arrowheads. Microbes from the pitch sample can thus reveal information about the oral health of the individuals who chewed it.
• For example, scientists from Finland, Norway, Sweden, and Turkey analysed DNA from three pieces of chewed pitch estimated to be around 9,500 years old, obtained from a site in Sweden.
• Upon sequencing the pitch samples, the scientists identified organisms associated with the sort of imbalance of microbial species observed in people with inflamed gums (periodontitis). The team also matched DNA with a number of plant and animal species, hinting at the ancient people’s diet.

 

What else can ancestral DNA reveal?

• Studies of aDNA could also provide big clues about the creation and development of stone tools. In the 1930s, for instance, researchers dug a cave in Ranis, Germany, where they identified a number of ancient stone tools.
• This site was believed to have been occupied by an old human population, from around 50,000 years ago, when modern humans, neanderthals, and denisovans coexisted. So the question was who actually made these tools.
• A tide of interest in this question prompted archaeologists to re-excavate the cave more recently, when they found several bone remains.
• When they sequenced genetic material from these bones using high-throughput sequencing, the DNA sequences they found unequivocally pointed in the direction of Homo sapiens. When they dated the samples using radiocarbon dating, the samples were found to be some 45,000 years old.

 

What are IPCC’s assessment reports?

(GS Paper 3, Environment)

Why in news?

• Since 1988, the UN Intergovernmental Panel on Climate Change (IPCC) has produced six assessment reports, three special reports, and methodology reports that provide guidelines for estimating greenhouse gas emissions and removal.
• Three reports from the IPCC’s sixth assessment cycle (AR6) were published in 2021-2022.
• These documents, prepared by scientists from the 195 countries that are part of the UN Framework Convention on Climate Change (FCCC), examine the science, consequences, adaptation, and vulnerability as well as the mitigation aspects of climate change.

 

What did the recent report say?

• The Sixth Assessment Report (AR6) warned that the time to limit the rise of the world’s average surface temperature to 1.5 degrees Celsius from the pre-industrial era as agreed in the Paris Agreement is running out.
• It also suggested some options and strategies to slow warming, and to adapt and build resilience in natural systems, in human-made systems, and in communities.
• After the AR6 synthesis report, the IPCC initiated its seventh cycle (AR7) by electing an IPCC bureau. In January 2024, bureau members met for the first time in Turkey to discuss budgeting issues, timelines for the various reports, and the work programme.
• The recent paper emphasised a recommendation by member countries to “ensure adequate input from the IPCC is available for the second global stocktake to be concluded in 2028”.

 

What is meant by ‘global stocktake’?

• To assess the world’s progress towards the goals of the Paris Agreement, UNFCCC countries conduct a ‘global stocktake’ (GST) every five years. The GST is a mechanism to measure collective progress, identify gaps, and chart a better course of climate action.
• The first GST started in 2022 and ended at the 28th session of the Conference of the Parties (COP28) to the UNFCCC in 2023.
• The first GST text, to which member countries agreed to at the COP28 in Dubai last year, requested the IPCC to consider ways in which its work can be aligned with subsequent stocktakes.
• The second GST is due in 2028; and member countries have requested the IPCC to publish its AR7 assessment reports before so that countries could measure their progress against the state of the planet.

 

What will the AR7 cycle produce?

• In Turkey, the Bureau agreed to produce the full assessment and synthesis reports, the methodology reports, and a special report. The full assessment reports will include reports from three Working Groups (as in the previous assessment cycles) plus a synthesis report.
• This decision considered the time available for significant new literature to be published, time required to run climate models, time to engage with under-represented communities, and the stress imposed on the IPCC technical support unit and the authors.
• The two methodology reports will be on short-lived climate forcers (like methane) and on carbon removal. The bureau also decided to revise the technical guidelines on impacts and adaptation.
• While countries suggested producing special reports spanning 28 topics, the bureau decided it will produce only one, on climate change and cities.

 

What is the timeline for reports?

• Several member countries also asked the bureau to ready the assessment reports by 2028 to coincide with the GST.
• But the bureau couldn’t reach a consensus on the release date, partly due to its experience with authors and countries over the time required to review, finalise, and publish the approved texts. Each assessment report in the past has required at least four years from start to finish.
• Countries also said a shortened cycle could compromise the content as not enough new research papers may be published in the window and modelling efforts to understand the changes in climate to the full extent may also remain incomplete.
• Many member countries also said a constrained timeline would complicate engagements with individuals and institutions in under-represented countries.
• A decision on the timeline with respect to the assessment reports is pending and will be taken at the 61st session of the IPCC. However, the special and methodology reports will be published in 2027.

 

Why OpenAI’s new video generator, Sora, is making a splash

(GS Paper 3, Science and Technology)

Context:

• OpenAI is in the spotlight again. This time, for building an artificial intelligence (AI) model that can create near flawless one-minute-long videos based on text prompt.
• The video creation AI model, called Sora, is trained on videos and images of various durations, resolutions, and aspect ratios to generate crisp, clear, and photorealistic output.
• While generating videos from texts aren’t new, Sora’s achievement dwarfs Meta’s Make-a-Video and Google’s recently announced Lumiere text-to-video tools. Unlike the output from Meta’s, Google’s, or other earlier AI video tools, Sora provides studio-grade final product.

What is Sora and what can it do?

• Sora in Japanese means sky, an imagery that evokes ‘limitless creative potential,’ per the company’s engineering team. This new diffusion-based AI model is built on the foundation of transformer architecture, similar to large language models like ChatGPT.
• It can create images and videos with near-accuracy on a given subject. It can construct a video from an image and also fill gaps in existing video clips.
• Diffusion models are used to generate high-quality images and videos. They are named after the physical diffusion process in which molecules move from high-concentration to low-concentration zones. In machine learning, these models generate new data by reversing the diffusion process.
• The simple idea here is to add noise to data and then reverse the visual data back to its original state by filtering out the noise.

 

How good is Sora’s output?

• The video clips generated by Sora are so photorealistic that they will stun anyone who looks at them for the first time. It is a top-class AI-based image generator. But a closer look reveals there is work to be done in object tracking.
• While OpenAI claims Sora can handle occlusion, a term in computer vision for objects disappearing when two or more of them come too close to each other, the text-to-video model does suffer from this limitation to an extent.
• For instance, in one of the clips shared by the Microsoft-backed company, people in the background disappear when the focus moves past a couple walking.
• Sora is not available to the public yet. The videos were handpicked by OpenAI so they may not be indicative of the tool’s average output. OpenAI plans to start sharing the model with third-party testers to receive feedback to improve the model.

 

What about the training data?

• OpenAI’s achievement through Sora is monumental and it will disrupt video creation and gaming industries. But the critical question on most people’s minds is on what visual data was Sora trained.
• Speculation is rife that the video generation tool was trained on data from game engines, movies, documentaries, YouTube videos, and possibly videos scraped from every corner of the web.
• The question of whether companies like OpenAI using unauthorised material scraped from the web to train AI violates copyright law is yet to be addressed by the courts.
• Tech firms claim they are protected by the copyright’s fair use doctrine and that lawsuits against them will stifle a growing AI industry.

 

What about misinformation?

• Photorealistic video generation capabilities are worrying considering the burgeoning misuse of generative AI tools to spread misinformation. This is possibly the reason why OpenAI took the red-teaming route ahead of its public launch.
• Sora already has a filter that will block prompt requests that mention violent, sexual, or hateful language, as well as images of well-known personalities.
• A second filter will check frames of generated videos and block content that violates the company’s safety guidelines.
• Sora uses a fake-image detector developed for DALL.E 3, but given the industriousness of bad actors, none of these steps are watertight.