{"id":59099,"date":"2025-11-13T19:01:45","date_gmt":"2025-11-13T13:31:45","guid":{"rendered":"https:\/\/www.nextias.com\/ca\/?p=59099"},"modified":"2025-11-15T12:28:02","modified_gmt":"2025-11-15T06:58:02","slug":"dna-sampling","status":"publish","type":"post","link":"https:\/\/www.nextias.com\/ca\/current-affairs\/13-11-2025\/dna-sampling","title":{"rendered":"DNA Sampling\u00a0"},"content":{"rendered":"\n<p><strong>Syllabus: GS3\/Science &amp; Technology<\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Context<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Investigators are using <strong>DNA profiling<\/strong> to determine the suspect of the recent deadly <strong>car explosion outside the Red Fort in New Delhi<\/strong>, highlighting how <strong>genetic analysis<\/strong> plays a crucial role in forensic investigations.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>About DNA Profiling<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>It is a set of <strong>molecular techniques<\/strong> used to identify individuals based on unique genetic markers.<\/li>\n\n\n\n<li>It remains the most dependable method of identification in cases involving explosions, fires, or mass disasters where bodies are unrecognisable.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background\" style=\"background-color:#ebecf0\"><tbody><tr><td><strong>Deoxyribonucleic Acid (DNA)<\/strong><br>&#8211; It is a molecule composed of two strands forming a double helix, carrying genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms.<br>&#8211; Each DNA molecule consists of<strong> four chemical bases:<\/strong> adenine (A), thymine (T), cytosine (C), and guanine (G).<br>1. The sequence of these bases determines genetic information.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Principles of DNA Profiling<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Short Tandem Repeats (STRs)<\/strong> as the most widely used markers.\n<ul class=\"wp-block-list\">\n<li>Each person has a distinctive STR pattern.<\/li>\n\n\n\n<li>Children inherit 50% of STR markers from each parent.<\/li>\n\n\n\n<li>A match between the mother\u2019s STR profile and that of an unidentified body can confirm identity with high accuracy.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Single Nucleotide Polymorphisms (SNPs) <\/strong>for higher resolution, useful for ancestry and medical applications.<\/li>\n\n\n\n<li><strong>Mitochondrial DNA (mtDNA) and Y-chromosome<\/strong><strong>markers <\/strong>for lineage tracing. If nuclear DNA is too degraded:\n<ul class=\"wp-block-list\">\n<li>mtDNA is used because it survives extreme conditions.<\/li>\n\n\n\n<li>It is inherited only from the mother.<\/li>\n\n\n\n<li>It is crucial for confirming maternal lineage, while it cannot uniquely identify individuals.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Techniques in DNA Profiling<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Polymerase Chain Reaction (PCR): <\/strong>It allows amplification of small or degraded DNA, and enables analysis of <strong>STR loci.<\/strong><\/li>\n\n\n\n<li><strong>Capillary Electrophoresis<\/strong>: It separates DNA fragments by size to generate STR profiles, and produces electropherograms used in identification.<\/li>\n\n\n\n<li><strong>Next-Generation Sequencing (NGS): <\/strong>It provides sequence-level variation of STRs and SNPs, and enables deeper resolution in ancestry mapping and complex forensic cases.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Applications of DNA Profiling in Genetic Analysis<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Forensic Identification: <\/strong>Crime scene investigation, missing-person cases, mass-disaster victim identification.<\/li>\n\n\n\n<li><strong>Medical Genetics: <\/strong>Detection of hereditary disorders using SNP-based profiling.\n<ul class=\"wp-block-list\">\n<li>Pharmacogenomics: matching drugs to patient genetic profiles.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Evolutionary and Population Genetics: <\/strong>Tracing migrations, genetic drift, founder effects.\n<ul class=\"wp-block-list\">\n<li>Measuring genetic diversity in populations.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Ancestry and Genealogy Testing: <\/strong>Comparing customer DNA to population reference panels.\n<ul class=\"wp-block-list\">\n<li>Use of autosomal SNP arrays and haplogroup analysis.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Conservation and Wildlife Biology: <\/strong>Tracking illegal wildlife trade.\n<ul class=\"wp-block-list\">\n<li>Identifying species, subspecies, and individuals in ecological studies.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background\" style=\"background-color:#fff2cc\"><tbody><tr><td><strong>How Genetic Analysis Establishes Identity?<\/strong><br>&#8211; <strong>DNA Extraction:<\/strong> Samples are taken from biological material \u2014 blood, bone, hair, or tissue \u2014 from both the unidentified remains and the known relative.<br>&#8211; <strong>PCR Amplification:<\/strong> PCR is used to amplify specific DNA regions for comparison.<br>&#8211; <strong>STR Profiling:<\/strong> STRs are highly variable DNA sequences used to create a genetic profile.<br>&#8211; <strong>Kinship Matching:<\/strong> The suspect\u2019s DNA is compared with that of the relative to establish a biological relationship.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Challenges in DNA Identification<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Degraded DNA: <\/strong>Heat, chemicals, or environmental exposure can break down genetic material.<\/li>\n\n\n\n<li><strong>Contamination: <\/strong>Poor handling or mixing of samples can compromise results.<\/li>\n\n\n\n<li><strong>Insufficient DNA: <\/strong>Some remains may yield very little biological material.<\/li>\n\n\n\n<li><strong>Mixed Profiles: <\/strong>In explosions, remains of multiple individuals may be intermingled, complicating analysis.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>India &amp; DNA Technology<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The <strong>DNA Technology (Use and Application) Regulation Bill, 2019<\/strong> was aimed to regulate the use of DNA technology for establishing identity in criminal investigations, missing persons cases, and disaster victim identification.\n<ul class=\"wp-block-list\">\n<li>The bill, <strong><em>though not passed<\/em><\/strong>, was aimed to:\n<ul class=\"wp-block-list\">\n<li>Establish a DNA Regulatory Board;<\/li>\n\n\n\n<li>Set standards for DNA laboratories;<\/li>\n\n\n\n<li>Ensure privacy and ethical use of genetic data.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>The <strong>Criminal Procedure (Identification) Act, 2022<\/strong> allows for the collection of DNA samples from arrestees, undertrials, and convicts.<\/li>\n\n\n\n<li>The<strong> Department of Biotechnology (DBT)<\/strong> under the Ministry of Science &amp; Technology supports research and infrastructure for DNA-based technologies, including biobanks and genomic studies.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Ethical, Legal, and Social Issues<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Privacy concerns and genetic data protection.<\/li>\n\n\n\n<li>Risks of genetic discrimination in insurance\/employment.<\/li>\n\n\n\n<li>Debates around national DNA databases.<\/li>\n\n\n\n<li>Informed consent and data ownership in consumer genetic platforms.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background\" style=\"background-color:#ebecf0\"><tbody><tr><td><strong>Other Methods of Genetic Analysis<\/strong><br>&#8211; <strong>Mendelian (Classical) Genetics:<\/strong><br>1. <strong>Segregation &amp; Independent Assortment Analysis:<\/strong> Used to determine how traits pass from parents to offspring based on predictable ratios.<br>2. <strong>Linkage &amp; Recombination Mapping: <\/strong>Measures how frequently alleles recombine during meiosis to infer physical proximity on chromosomes.<br>&#8211; <strong>Cytogenetic Methods:<\/strong><br>1. <strong>Karyotyping: <\/strong>Examines whole chromosome structures to detect aneuploidies and gross chromosomal changes.<br>2. <strong>Fluorescence In Situ Hybridization (FISH): <\/strong>Uses fluorescent probes to detect specific DNA sequences on chromosomes.<br>3. <strong>Comparative Genomic Hybridization (CGH): <\/strong>Identifies chromosomal gains and losses without requiring cell culture.<br>&#8211; <strong>Functional Genetic Analysis:<\/strong><br>1. <strong>Gene Knockout\/Knock-in (CRISPR, TALEN, ZFN): <\/strong>Used to study gene function by disrupting or altering gene sequences.<br>2. <strong>RNA Interference (RNAi): <\/strong>Silences gene expression to observe phenotypic changes.<br>3. <strong>Overexpression Systems: <\/strong>Increase gene expression to determine function.<br>&#8211; <strong>Epigenetic Analysis:<\/strong><br>1. <strong>Bisulfite Sequencing: <\/strong>Maps DNA methylation.<br>2. <strong>ChIP-seq: <\/strong>Identifies protein\u2013DNA interactions and histone modifications.<br>3. <strong>ATAC-seq: <\/strong>Profiles chromatin accessibility.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><a href=\"https:\/\/indianexpress.com\/article\/cities\/delhi\/red-fort-blast-aiims-dna-pulwama-parents-key-case-10361012\/\" target=\"_blank\" rel=\"noopener\">Source: IE<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p><strong>Context<\/strong><\/p>\n<li class=\"ms-5\">Investigators are using DNA profiling to determine the suspect of the recent deadly car explosion outside the Red Fort in New Delhi, highlighting how genetic analysis plays a crucial role in forensic investigations.<\/li>\n<p><\/p>\n<p><strong>About DNA Profiling<\/strong><\/p>\n<li class=\"ms-5\">It is a set of molecular techniques used to identify individuals based on unique genetic markers.<\/li>\n<li class=\"ms-5\">It remains the most dependable method of identification in cases involving explosions, fires, or mass disasters where bodies are unrecognisable.<\/li>\n<p><a href=\"https:\/\/www.nextias.com\/ca\/current-affairs\/13-11-2025\/dna-sampling\" class=\"btn btn-primary btn-sm float-end\">Read\u00a0More<\/a><\/p>\n","protected":false},"author":15,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[21],"tags":[],"class_list":["post-59099","post","type-post","status-publish","format-standard","hentry","category-current-affairs"],"acf":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/59099","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/comments?post=59099"}],"version-history":[{"count":2,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/59099\/revisions"}],"predecessor-version":[{"id":59114,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/59099\/revisions\/59114"}],"wp:attachment":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/media?parent=59099"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/categories?post=59099"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/tags?post=59099"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}