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Scientists from the Birbal Sahni Institute of Palaeosciences (BSIP), Lucknow - an autonomous institute of the Department of Science and Technology - with the University of Chicago and collaborators in India, Sri Lanka and the USA, have found that South Asian gut microbiomes are distinct from those reported elsewhere and are shaped by local culture, diet, geography and lifestyle.
Stool samples with dietary, lifestyle and health information were collected from 575 healthy adults across ten culturally and geographically distinct South Asian communities in India and Sri Lanka, and characterised by high-throughput sequencing of bacterial 16S rRNA genes.
The work created the South Asian MicroBiome ARray (SAMBAR), described as the first baseline gut microbiome resource from healthy individuals in India, and was published in the journal Gut Microbes; the team was led by Dr Niraj Rai of BSIP, with Maanasa Raghavan and colleagues.
The gut microbiome is the community of bacteria, archaea, fungi and viruses living in the human digestive tract, together with their genes. These organisms ferment dietary fibre the human body cannot digest, produce short-chain fatty acids and certain vitamins, train the immune system and resist colonisation by pathogens. Their composition is shaped by diet, geography, medication - especially antibiotics - and lifestyle, which is why an urbanising population's microbiome changes. Reading the community works in two main ways. Sequencing the bacterial 16S ribosomal RNA gene is the cheaper, standard approach: the gene is present in all bacteria and contains regions that are conserved across species (so a single pair of primers amplifies everything) interspersed with variable regions unique enough to identify who is present and in what relative abundance. Shotgun metagenomics sequences all DNA in the sample and tells you not only who is there but what functions their genes can perform. This study used the 16S route across 575 individuals to build a population-scale baseline.
Simple Analogy: 16S sequencing is a roll call - it tells you which species are in the room and roughly how many of each. Shotgun metagenomics is reading everyone's CV - slower and costlier, but it tells you what they can actually do.
An autonomous research institution funded by the Department of Science and Technology, established in 1946 on the vision of Professor Birbal Sahni, the palaeobotanist. It was formerly the Birbal Sahni Institute of Palaeobotany and was renamed to reflect a broadened mandate covering palaeosciences generally - which is how a palaeoscience institute comes to run an ancient DNA group and, from it, a modern human microbiome study.
Established in May 1971 as the nodal department for organising, coordinating and promoting science and technology activities in India and for opening up new areas of science. It funds a network of autonomous institutions, of which BSIP is one.
Comprises three departments - the Department of Science and Technology (1971), the Department of Biotechnology (1986) and the Department of Scientific and Industrial Research (1985), the last of which administers CSIR. Distinguishing which department funds which institute is a standard examination point.
The reference effort run by the United States National Institutes of Health, launched in 2008, which characterised the microbiome of healthy individuals by collecting microbial DNA from multiple body sites and combining 16S rRNA tag sequencing with shotgun metagenomics. It is the model that SAMBAR extends to a population it did not cover.
Probiotics are, in the FAO/WHO formulation, live micro-organisms which when administered in adequate amounts confer a health benefit on the host. Prebiotics are non-digestible food substances that pass the upper gut intact and are fermented by gut bacteria, selectively favouring beneficial species. A population-specific baseline like SAMBAR is what makes it possible to say which strains are worth supplementing in which community, rather than importing Western formulations wholesale.
The study's stated motivation is the sharp rise in obesity, diabetes and cardiometabolic disorders across a rapidly urbanising South Asia. Gut microbial composition is implicated in energy harvest from food, insulin sensitivity and inflammation, which is why a microbiome baseline is being framed as public health infrastructure rather than pure science.
Antibiotics reshape the gut microbiome and the gut is a reservoir where resistance genes are exchanged between species. Baseline microbiome data from healthy people is the reference against which antibiotic-driven disruption and resistance-gene carriage can be measured.
BSIP's Ancient DNA group works on the genetic history of South Asian populations. The same laboratory and computational infrastructure - DNA extraction from degraded or complex samples, high-throughput sequencing, population-level bioinformatics - is what allowed a palaeoscience institute to lead a contemporary microbiome study.
The release makes an explicit equity argument: most microbiome research has been done on European and North American populations, so therapies derived from it may not transfer. The same argument runs through genomics more widely and underlies India's own population genome initiatives.
GS Paper 3 > Science and Technology > Biotechnology, Genomics and Health
General Science > Biology and Research Institutions
General Science > Human Biology
Consider the following statements in respect of probiotics: 1. Probiotics are made of both bacteria and yeast. 2. The organisms in probiotics are found in foods we ingest but they do not naturally occur in our gut. 3. Probiotics help in the digestion of milk sugars. Which of the statements given above is/are correct?
Answer: 1 and 3
Microbiome and genomics topics appear irregularly in Prelims but institute-and-department pairings are asked in nearly every SSC and railway cycle.
The community of micro-organisms in the human digestive tract together with their collective genes; it ferments fibre, produces short-chain fatty acids and vitamins and trains the immune system.
Sequencing of a bacterial ribosomal RNA gene that has both conserved and variable regions, used to identify which bacteria are present and in what relative abundance.
Sequencing all genetic material in an environmental sample to determine both the organisms present and the functions their genes encode.
Live micro-organisms which, when administered in adequate amounts, confer a health benefit on the host (FAO/WHO).
A non-digestible food substance that passes the upper gut intact and is fermented by gut bacteria, selectively promoting beneficial species.
Tailoring dietary advice to an individual's or population's biology - including microbiome composition - rather than applying a single universal guideline.