This question bridges NCERT Class 12 Biology (Molecular Basis of Inheritance) and Environment Current Affairs (Tiger Census). While 'Microsatellite' sounds technical, it is the fundamental basis of 'DNA Fingerprinting' mentioned in every standard text. The strategy is to link the 'tool' (DNA profiling) with its 'component' (Microsatellites/STRs).
How this question is built
This question can be broken into the following sub-statements.
Tap a statement sentence to jump into its detailed analysis.
Statement 1
Is microsatellite DNA used to study evolutionary relationships among various species of fauna?
Origin: Web / Current Affairs
Fairness: CA heavy
Web-answerable
"Micro-satellite DNA analysis is useful to study genetic relationships between populations (Ambali and Doyle 1997) and allozymes have been studied to determine phylogenetic relationships (Agnèse et al. 1997)."
Why this source?
- Directly states microsatellite DNA analysis is useful to study genetic relationships between populations.
- Links microsatellite analysis to genetic/phylogenetic work in fish (fauna) contexts.
"Stock origin of migratory Atlantic Sturgeon in Minas Basin, Inner Bay of Fundy, Canada, determined by microsatellite and mitochondrial DNA analyses. ... Comparison of mitochondrial DNA control region sequence and microsatellite DNA analyses in estimating population structure and gene flow rates in Atlantic sturgeon Acipenser oxyrinchus."
Why this source?
- Shows microsatellite DNA analyses being used to determine stock origin and population structure in Atlantic sturgeon (a faunal species).
- Compares microsatellite and mitochondrial DNA for estimating population structure and gene flow, indicating use in evolutionary/relationship studies.
"Molecular markers: A DNA marker is an identifiable DNA fragment or sequence that can be used to detect DNA polymorphism. Molecular markers have a number of uses including estimation of population histories and genetic relationships within and between animal breeds (molecular characterization), as well as the determination of parentage."
Why this source?
- Describes molecular markers (a category that includes microsatellites) as tools for estimating population histories and genetic relationships within and between animal breeds.
- Links molecular markers to molecular characterization and determination of relationships in animals, supporting their use in evolutionary studies of fauna.
History , class XI (Tamilnadu state board 2024 ed.) > Chapter 1: Early India: From the Beginnings to the Indus Civilisation > Sources > p. 1
Strength: 4/5
βThe human genes also constitute an important source for understanding prehistoric migrations. The mitochondrial DNA (mt-DNA) studies provide information on pre-historic migrations. Scientists are trying to extract ancient DNA from the bones of the prehistoric era to understand human dispersals. Language is another important source of history. Indo-Aryan, Dravidian, Austro-Asiatic and Tibeto-Burman language families have flourished in India. These languages developed and evolved during the various phases of migrations in Indian history.β
Why relevant
States that mitochondrial DNA studies provide information on prehistoric migrations and human dispersals, showing DNA markers are used to infer historical/evolutionary relationships.
How to extend
A student can generalize that other genetic markers (e.g., microsatellites) may likewise be used to study evolutionary or population relationships among animals and check specialized literature on microsatellite applications.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > Goals: > p. 249
Strength: 4/5
ββ’ Deliver DNA barcoding technology for 5 million species. β’ Develop the informatics platform and analytical protocols required for the development of a DNA barcode reference library. β’ Establish a core facility to provide sequencing and informatics support.
β’ Complete the census of all multicellular species.
β’ Establish a global biosurveillance program.
β’ Construct a 'library of life' by preserving DNA extracts from all species.β
Why relevant
Calls for DNA barcoding, a program to sequence standard gene regions and build reference libraries for species identification β an example of using DNA sequences to study species-level relationships.
How to extend
A student could infer that different types of genetic markers (including short repetitive markers like microsatellites) are part of the toolbox for studying species relationships and population structure.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.r.3. Estimation of Tiger Populations > p. 229
Strength: 5/5
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individuals. Now it is largely used as one of the indices of tiger occurrence and relative abundance.
β’ I Recent methods used to estimate the numbers of tigers are camera trapping and DNA fingerprinting. β’ In camera trapping, the photograph of the tiger is taken and individuals are differentiated on the basis of the stripes on the body. β’ In the latest technique of DNA fingerprinting, tigers can be identified from their scats.β
Why relevant
Describes DNA fingerprinting for individual identification of tigers from scats, demonstrating practical use of genetic markers in fauna studies and conservation.
How to extend
From this, a student might extend that microsatellites β commonly used in DNA fingerprinting and population genetics β can be applied to study relationships and population structure in other animal species.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.17. DNA BARCODING > p. 248
Strength: 3/5
βA MoU signed between Zoological Survey of India (ZSI), a subordinate organization under MoEF&CC, and International Barcode of Life (iBOL), a Canadian not-for-profit corporation. ZSI and iBOL have come together for further efforts in DNA barcoding, a methodology for rapidly and accurately identifying species by sequencing a short segment of standardized gene regions and comparing individual sequences to a reference database. iBOL is a research alliance involving nations that have committed both human and financial resources to enable expansion of the global reference database, the development of informatics platforms, and/or the analytical protocols needed to use the reference library to inventory, assess, and describe biodiversity.β
Why relevant
Explains DNA barcoding as sequencing standardized gene regions and comparing to a reference database to identify species β an explicit example of sequencing-based methods applied to biodiversity studies.
How to extend
A student could reason that beyond barcoding loci, other genetic markers (such as microsatellites) serve complementary roles in resolving evolutionary and population-level questions.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 8: Biodiversity > ffiIffiffi > p. 143
Strength: 3/5
β'F' iodiversity found on Earth today consists of millions of distinct biological species, which is a product of four billion years of evolution. Biodiversity refers to the variety of life on Earth, encompassing all organisms, species, and populations; the genetic variation among these; and their complex assemblages of communities and ecosystems. It also includes the interrelatedness of genes, species, and ecosystems, along with their interactions with the environment.β
Why relevant
Defines biodiversity to include genetic variation among organisms, highlighting that genetic data are central to understanding relationships among species and populations.
How to extend
A student can use this principle to justify why molecular markers (including microsatellites) are relevant tools for studying evolutionary relationships among fauna.
Statement 2
Is microsatellite DNA used to stimulate stem cells to transform into diverse functional tissues?
Origin: Weak / unclear
Fairness: Borderline / guessy
Indirect textbook clues
Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Activity 6.2 > p. 108
Strength: 4/5
βIf, instead of generating an electrical impulse, stimulated cells release a chemical compound, this compound would diffuse all around the original cell. If other cells around have the means to detect this compound using special molecules on their surfaces, then they would be able to recognise information, and even transmit it. This will be slower, of course, but it can potentially reach all cells of the body, regardless of nervous connections, and it can be done steadily and persistently. These compounds, or hormones used by multicellular organisms for control and coordination show a great deal of diversity, as we would expect.β
Why relevant
Describes that stimulated cells can release chemical compounds which other cells detect and respond to β a general rule that chemical signals can change cell behaviour.
How to extend
A student could extend this by noting microsatellite-derived factors would need to act like such signalling molecules or influence their production to steer stem cell differentiation.
Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > 8.2.3 How do these Traits get Expressed? > p. 131
Strength: 4/5
βHow does the mechanism of heredity work? Cellular DNA is the information source for making proteins in the cell. A section of DNA that provides information for one protein is called the gene for that protein. How do proteins control the characteristics that we are discussing here? Let us take the example of tallness as a characteristic. We know that plants have hormones that can trigger growth. Plant height can thus depend on the amount of a particular plant hormone. The amount of the plant hormone made will depend on the efficiency of the process for making it. Consider now an enzyme that is important for this process.β
Why relevant
Explains that DNA (genes) encodes proteins and that hormones (chemical signals) control traits like growth β linking DNA sequence to production of molecules that change cell fate.
How to extend
One could infer that if microsatellite DNA affects gene expression, it might alter production of proteins/hormones that direct stem cells toward specific tissue types.
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > How do Organisms Reproduce? CHAPTER7 > p. 116
Strength: 3/5
βThis is not true for all multi-cellular organisms. They cannot simply divide cell-by-cell. The reason is that many multi-cellular organisms, as we have seen, are not simply a random collection of cells. Specialised cells are organised as tissues, and tissues are organised into organs, which then have to be placed at definite positions in the body. In such a carefully organised situation, cell-by-cell division would be impractical. Multi-cellular organisms, therefore, need to use more complex ways of reproduction. A basic strategy used in multi-cellular organisms is that different cell types perform different specialised functions. Following this general pattern, reproduction in such organisms is also the function of a specific cell type.β
Why relevant
States multicellular organisms use specialised cell types and tissues β a pattern showing that distinct molecular programs yield specialised functions.
How to extend
A student could reason that stimulating stem cells must change their molecular program to produce specialised tissues, so any candidate (e.g., microsatellite DNA) would need to influence those programs.
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.3.1 Why the Sexual Mode of Reproduction? > p. 120
Strength: 3/5
βreproduction incorporates such a process of combining DNA from two different individuals during reproduction. But this creates a major difficulty. If each new generation is to be the combination of the DNA copies from two pre-existing individuals, then each new generation will end up having twice the amount of DNA that the previous generation had. This is likely to mess up the control of the cellular apparatus by the DNA. How many ways can we think of for solving this difficulty? We have seen earlier that as organisms become more complex, the specialisation of tissue increases. One solution that many multi-cellular organisms have found for the problem mentioned above is to have special lineages of cells in specialised organs in which only half the number of chromosomes and half the amount of DNA as compared to the nonreproductive body cells.β
Why relevant
Notes existence of specialised cell lineages with different chromosome/DNA content for particular functions, illustrating that DNA configuration relates to specialized cell roles.
How to extend
This supports extending the idea that alterations in DNA or its regulatory regions could be implicated in directing cells to particular fates, a prerequisite for claims about microsatellite involvement.
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.1 DO ORGANISMS CREATE EXACT COPIES OF THEMSEL THEMSELVES? > p. 114
Strength: 2/5
βbecause the copy pushed out would not have any organised cellular structure for maintaining life processes. Therefore, DNA copying is accompanied by the creation of an additional cellular apparatus, and then the DNA copies separate, each with its own cellular apparatus. Effectively, a cell divides to give rise to two cells. These two cells are of course similar, but are they likely to be absolutely identical? The answer to this question will depend on how accurately the copying reactions involved occur. No bio-chemical reaction is absolutely reliable. Therefore, it is only to be expected that the process of copying the DNA will have some variations each time.β
Why relevant
Points out DNA copying is imperfect and generates variations β a general example that DNA sequence differences can lead to different cellular outcomes.
How to extend
A student might use this to reason that sequence repeats (microsatellites) could influence gene function/variation and thus be hypothesised to affect differentiation, warranting experimental testing.
Statement 3
Is microsatellite DNA used to promote clonal propagation of horticultural plants?
Origin: Weak / unclear
Fairness: Borderline / guessy
Indirect textbook clues
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.2.5 Vegetative Propagation > p. 117
Strength: 4/5
βThere are many plants in which parts like the root, stem and leaves develop into new plants under appropriate conditions. Unlike in most animals, plants can indeed use such a mode for reproduction. This property of vegetative propagation is used in methods such as layering or grafting to grow many plants like sugarcane, roses, or grapes for agricultural purposes. Plants raised by vegetative propagation can bear flowers and fruits earlier than those produced from seeds. Such methods also make possible the propagation of plants such as banana, orange, rose and jasmine that have lost the capacity to produce seeds. Another advantage of vegetative propagation is that all plants produced are genetically similar enough to the parent plant to have all its characteristics.β
Why relevant
Explains vegetative propagation produces plants genetically similar to the parent, i.e., clonal propagation is used in horticulture (sugarcane, roses, grapes).
How to extend
A student could infer that genetic markers (like microsatellites) might be useful to identify or verify these clonally propagated plants or to select parent material for propagation.
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > Tissue culture > p. 118
Strength: 5/5
βIn tissue culture, new plants are grown by removing tissue or separating cells from the growing tip of a plant. The cells are then placed in an artificial medium where they divide rapidly to form a small group of cells or callus. The callus is transferred to another medium containing hormones for growth and differentiation. The plantlets are then placed in the soil so that they can grow into mature plants. Using tissue culture, many plants can be grown from one parent in disease-free conditions. This technique is commonly used for ornamental plants.β
Why relevant
Describes tissue culture as a technique to grow many plants from one parent in disease-free conditions, a common method for producing multiple identical horticultural plants.
How to extend
One could extend this to ask whether molecular markers (e.g., microsatellites) are used to monitor genetic fidelity or to screen for somaclonal variation among tissue-cultured clones.
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > QUESTIONS > p. 119
Strength: 3/5
ββ’ 1. How does binary fission differ from multiple fission?β’ 2. How will an organism be benefited if it reproduces through spores?β’ 3. Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?β’ 4. Why is vegetative propagation practised for growing some types of plants?β’ 5. Why is DNA copying an essential part of the process of reproduction?β
Why relevant
Notes vegetative propagation is practised for growing some types of plants, highlighting the horticultural reliance on asexual/clonal methods.
How to extend
This suggests testing whether molecular tools are applied in horticulture to confirm clonality or to select propagules, raising the possibility microsatellite markers could be used for that purpose.
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Sisal (Agave sisalana) > p. 53
Strength: 3/5
βTop soil should be disturbed as little as possible and infertile sub-soil should not be exposed. Ploughing to a depth of 15-20 cm is adequate. Sisal plants rarely set seeds. Propagation of sisal is done by bulbils and suckers which are asexual source of propagation. Te sisal plant produces nearly 500-2000 bulbils. Bulbils are collected from mid-February to mid-April. Te process of extracting the fbre from leaf tissues of sisal is called decortications. Extracting of fbre is preferably done on the same day or within 48 hours from the time of harvesting. Decorticated fbre is washed in clean water and dried in the sun for removing moisture.β
Why relevant
Gives a concrete example (sisal) where propagation is done by bulbils and suckers because seed set is rare β an instance of routine clonal propagation in crops.
How to extend
A student could reason that for crops propagated asexually, genetic assays (such as microsatellites) may be employed to track genetic identity or variability in propagules.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Beneficial effects of weeds > p. 365
Strength: 2/5
βColonum occurs in rich soils while Cymbopogon denotes poor light soil and Sedges are found in ill-drained soils Genetically modified crops (GM crops, or biotech crops) are plants, the DNA of which has been modified using genetic engineering techniques, which are then used in agriculture.β
Why relevant
Mentions genetically modified crops as plants whose DNA has been modified using genetic engineering techniques, linking horticulture to DNA-level interventions.
How to extend
From this one might extend to consider other DNA-based techniques (like molecular marker analysis) being applied in horticulture to support propagation or breeding decisions.
Statement 4
Is microsatellite DNA used to assess the efficacy of drugs when conducting drug trials in a population?
Origin: Weak / unclear
Fairness: Borderline / guessy
Indirect textbook clues
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.r.3. Estimation of Tiger Populations > p. 229
Strength: 4/5
β5I{ANKAR
individuals. Now it is largely used as one of the indices of tiger occurrence and relative abundance.
β’ I Recent methods used to estimate the numbers of tigers are camera trapping and DNA fingerprinting. β’ In camera trapping, the photograph of the tiger is taken and individuals are differentiated on the basis of the stripes on the body. β’ In the latest technique of DNA fingerprinting, tigers can be identified from their scats.β
Why relevant
Mentions "DNA fingerprinting" as a method to identify individuals from biological samples, showing that molecular genetic markers are used to track individuals/populations.
How to extend
A student could infer that if genetic markers can identify individuals, similar markers (e.g., microsatellites) might be used to track genetic-related outcomes or stratify subjects in drug trials and then check specialized sources on pharmacogenetic markers.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > Innovations in Zoro National Tiger Assessment > p. 230
Strength: 3/5
βr Partnerships with civil society organizations
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β’ Local communities involved in data collection and analysis.
β’ Genetic analysis to estimate tiger populations from faecal samples.
β’ Along with tigers, co-predators, prey, and habitat quality assessed.
β’ Pioneering attempt to estimate tiger populations in Sunderbans Tiger Reserve (West Bengal) using satellite telemetry and sign surveys.
β’ First estimation of tiger population in Sahyadri Tiger Reserve (Maharashtra).β
Why relevant
Describes "genetic analysis to estimate tiger populations from faecal samples," indicating genetics is applied to monitor populations noninvasively.
How to extend
A student could reason that genetic assays used to monitor populations could be adapted to monitor biological responses in human cohorts during trials and then look for literature on markers used in clinical studies.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.17. DNA BARCODING > p. 248
Strength: 3/5
βA MoU signed between Zoological Survey of India (ZSI), a subordinate organization under MoEF&CC, and International Barcode of Life (iBOL), a Canadian not-for-profit corporation. ZSI and iBOL have come together for further efforts in DNA barcoding, a methodology for rapidly and accurately identifying species by sequencing a short segment of standardized gene regions and comparing individual sequences to a reference database. iBOL is a research alliance involving nations that have committed both human and financial resources to enable expansion of the global reference database, the development of informatics platforms, and/or the analytical protocols needed to use the reference library to inventory, assess, and describe biodiversity.β
Why relevant
Explains DNA barcoding and sequencing standardized gene regions for identification, demonstrating use of short DNA regions as reliable markers.
How to extend
A student could extend this to ask whether short repetitive markers (like microsatellites) are similarly standardized for tracking genetic variation relevant to drug response and search pharmacogenetics resources.
THEMES IN INDIAN HISTORY PART I, History CLASS XII (NCERT 2025 ed.) > Chapter 1: Bricks, Beads and Bones > 10.1 Cunningham's confusion > p. 19
Strength: 3/5
βGiven his specific focus, it is not surprising that he missed the significance of Harappa. Archaeogenetics is the study of DNA of ancient population. It involves various methods of molecular genetics to understand population history.β
Why relevant
Defines archaeogenetics as use of molecular genetics to study population history, showing that genetic marker analyses are standard tools in population-level studies.
How to extend
A student could use this pattern to hypothesize that population-level genetics (including microsatellites) can be applied to study variability in drug response across populations and then verify in clinical genetics literature.
Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.3.1 Why the Sexual Mode of Reproduction? > p. 119
Strength: 2/5
βThe creation of two new cells from one involves copying of the DNA as well as of the cellular apparatus. The DNA copying mechanism, as we have noted, cannot be absolutely accurate, and the resultant errors are a source of variations in populations of organisms. Every individual organism cannot be protected by variations, but in a population, variations are useful for ensuring the survival of the species. It would therefore make sense if organisms came up with reproductive modes that allowed more and more variation to be generated. While DNA-copying mechanisms are not absolutely accurate, they are precise enough to make the generation of variation a fairly slow process.β
Why relevant
Discusses DNA copying errors as sources of variation in populations, highlighting that genetic variation exists and can be measured.
How to extend
A student could combine this with knowledge that drug efficacy can vary with genetic differences and then investigate whether microsatellites are among markers used to correlate genotype with drug response.
Pattern takeaway:
UPSC is shifting from asking 'What is the application?' (e.g., Tiger Census) to 'What is the underlying technology?' (e.g., Microsatellites, M-STrIPES). Always prepare the 'Science behind the Scheme'.
How you should have studied
- [THE VERDICT]: Conceptual Sitter for Science students; Moderate for others. Source: NCERT Class 12 Biology, Chapter 6 (Human Genome Project & DNA Fingerprinting) + Tiger Census methodology.
- [THE CONCEPTUAL TRIGGER]: 'DNA Fingerprinting' and 'Genetic Markers' used in Wildlife Conservation (Project Tiger).
- [THE HORIZONTAL EXPANSION]: Memorize these Genetic Tools: 1) Microsatellites (STRs) = Paternity/Forensics/Population structure. 2) Minisatellites (VNTRs) = Older fingerprinting tech. 3) Mitochondrial DNA (mtDNA) = Maternal lineage/Evolutionary tracking. 4) SNPs (Single Nucleotide Polymorphisms) = Drug response/Precision medicine. 5) eDNA (Environmental DNA) = Detecting species from water/soil samples.
- [THE STRATEGIC METACOGNITION]: When you read 'Tiger Census uses DNA fingerprinting from scat,' ask 'What exactly in the DNA is being measured?' The answer is Microsatellites. UPSC tests the *mechanism* behind the *headline*.
Concept hooks from this question
π DNA barcoding for species identification
π‘ The insight
DNA barcoding is a standardized short-gene sequencing method used to identify species rapidly and accurately.
High-yield for questions on biodiversity inventory and conservation policy because it links molecular techniques to species-level identification and global initiatives like building reference libraries; connects to bioinformatics and national biodiversity programmes and enables questions on technological tools for conservation.
π Reading List :
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.17. DNA BARCODING > p. 248
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > Goals: > p. 249
π Anchor: "Is microsatellite DNA used to study evolutionary relationships among various spe..."
π Mitochondrial DNA for tracing population history
π‘ The insight
Mitochondrial DNA is used to infer prehistoric migrations and maternal lineage relationships.
Important for topics on human migrations, evolutionary history and phylogeography; helps answer questions that connect genetics with historical demography and patterns of dispersal.
π Reading List :
- History , class XI (Tamilnadu state board 2024 ed.) > Chapter 1: Early India: From the Beginnings to the Indus Civilisation > Sources > p. 1
π Anchor: "Is microsatellite DNA used to study evolutionary relationships among various spe..."
π DNA fingerprinting in wildlife monitoring
π‘ The insight
DNA fingerprinting enables identification of individual animals from biological samples and aids population estimation.
Directly relevant to conservation practice and wildlife census methods (camera trapping vs genetic identification); useful for questions on methods to estimate and monitor endangered species and forensics in wildlife protection.
π Reading List :
- Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > 16.r.3. Estimation of Tiger Populations > p. 229
- Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 4: BIODIVERSITY > Ex-situ conservation > p. 30
π Anchor: "Is microsatellite DNA used to study evolutionary relationships among various spe..."
π Cell specialization and tissue organization
π‘ The insight
Multicellular organisms form specialised cell types that are organised into tissues and organs, which is the outcome targeted when converting stem cells into functional tissues.
High-yield for questions on development, regeneration and reproductive biology; links cellular differentiation to physiology and organ-level function. Mastery helps answer questions on how cellular-level manipulations (like stem-cell work) must respect tissue organisation and specialised roles.
π Reading List :
- Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > How do Organisms Reproduce? CHAPTER7 > p. 116
- Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > 5.1 WHAT ARE LIFE PROCESSES? > p. 80
π Anchor: "Is microsatellite DNA used to stimulate stem cells to transform into diverse fun..."
π Gene-to-protein control of traits and hormonal triggers
π‘ The insight
Genes encode proteins that control cellular functions and hormones can trigger growth and physiological responses relevant to driving cell behaviour and differentiation.
Essential for genetics, endocrinology and developmental biology questions; explains mechanisms by which molecular signals can direct cell fate and tissue formation. Useful for evaluating interventions that aim to change cell behaviour by altering signalling or gene expression.
π Reading List :
- Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > 8.2.3 How do these Traits get Expressed? > p. 131
- Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Activity 6.2 > p. 108
π Anchor: "Is microsatellite DNA used to stimulate stem cells to transform into diverse fun..."
π DNA replication, variation and chromosomal basis of heredity
π‘ The insight
Accurate DNA copying, chromosome complement and the generation of variation underlie cellular identity and stability, which constrain how cells can be manipulated or reprogrammed.
Core for genetics and reproduction topics; helps reason about limits of genetic interventions, stability of engineered cells, and inheritance of cellular properties. Prepares candidates to connect molecular fidelity to larger biological outcomes.
π Reading List :
- Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.1 DO ORGANISMS CREATE EXACT COPIES OF THEMSEL THEMSELVES? > p. 114
- Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.3.1 Why the Sexual Mode of Reproduction? > p. 120
- Science , class X (NCERT 2025 ed.) > Chapter 8: Heredity > separate traits, shape and colour of seeds Figure 8.5 > p. 132
π Anchor: "Is microsatellite DNA used to stimulate stem cells to transform into diverse fun..."
π Vegetative (asexual) propagation / clonal propagation
π‘ The insight
Vegetative propagation reproduces plants from roots, stems or leaves to produce genetically similar (clonal) plants.
High-yield topic for horticulture questions: explains how clonal uniformity, early flowering and propagation of seedless cultivars are achieved. Connects to crop-management, nursery practices and distinctions between sexual vs asexual reproductionβuseful for questions on propagation methods and advantages/disadvantages.
π Reading List :
- Science , class X (NCERT 2025 ed.) > Chapter 7: How do Organisms Reproduce? > 7.2.5 Vegetative Propagation > p. 117
- Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet > 13.5.1 Asexual reproduction > p. 220
π Anchor: "Is microsatellite DNA used to promote clonal propagation of horticultural plants..."
Next Logical Question: 'Environmental DNA (eDNA)'. Since they asked about Microsatellites (tissue/scat analysis), the next step is eDNA (detecting species presence from water/soil without physical samples), which is currently revolutionizing biodiversity monitoring.
β‘ Elimination Cheat Code
Etymology Hack: 'Satellite' in genetics refers to highly repetitive DNA. Repetitive things are unique to individuals/lineages (like fingerprints). Option B (Stem cells) and D (Drug trials) usually involve functional genes (coding regions), not repetitive 'junk' DNA. Option C is about growing plants. Option A (Evolutionary relationships) is the only one dealing with 'tracking lineage' or 'identity,' which is what fingerprints do.
Mains GS-3 (Science & Tech + Environment): Use this to argue for 'Non-invasive Conservation Technologies.' Genetic monitoring allows tracking of endangered species (like Cheetahs in Kuno) without the stress of physical capture.