{"id":45541,"date":"2025-06-16T21:30:02","date_gmt":"2025-06-16T16:00:02","guid":{"rendered":"https:\/\/www.nextias.com\/ca\/?p=45541"},"modified":"2025-07-03T13:23:45","modified_gmt":"2025-07-03T07:53:45","slug":"how-dna-identification-works","status":"publish","type":"post","link":"https:\/\/www.nextias.com\/ca\/current-affairs\/16-06-2025\/how-dna-identification-works","title":{"rendered":"How DNA Identification Works?"},"content":{"rendered":"\n<p><strong>Syllabus: GS3\/Science and 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>After the Air India Boeing 787 Dreamliner crash in Ahmedabad, authorities are <strong>using <a href=\"https:\/\/www.nextias.com\/ca\/current-affairs\/07-01-2025\/genomic-history-early-medieval-europe\">DNA analysis<\/a> to identify the remains<\/strong> of those killed in the accident.\u00a0<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>About<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>With the exception of identical twins,<strong> every person has a unique DNA<\/strong> that is present in nearly every cell of their body.&nbsp;<\/li>\n\n\n\n<li>DNA identification is the gold standard for identifying human remains, especially after <strong>mass fatality events<\/strong> in which bodies might not be easy to identify otherwise.<\/li>\n<\/ul>\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>DNA Degradation: <\/strong>It begins immediately after death and affects analysis accuracy.<\/li>\n\n\n\n<li><strong>Factors Impacting Degradation:<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Tissue type: <\/strong>Soft tissues degrade faster than hard tissues (bones, teeth).<\/li>\n\n\n\n<li><strong>Environmental conditions:<\/strong> DNA survives better in cold and dry conditions than in hot and humid ones.<\/li>\n\n\n\n<li><strong>Sample Collection Timeline: <\/strong>Delays can further degrade DNA.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Preservation of DNA Samples<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Samples have to be <strong>collected as soon as possible<\/strong>, and once collected, stored in a <strong>cool and dry environment<\/strong>.&nbsp;<\/li>\n\n\n\n<li>They should ideally be<strong> frozen at minus 20 degrees Celsius<\/strong>, or, in the case of soft tissues (skin, muscles, etc.), they may be stored in <strong>95% ethanol.<\/strong><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Methods of DNA Analysis<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Reference DNA <\/strong>is needed to <strong>match unidentified remains.<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Ideal sources: <\/strong>Parents and children (share 50% of DNA).<\/li>\n\n\n\n<li><strong>Other possible sources: <\/strong>Maternal or paternal relatives depending on the method used.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Depending on the quality of the collected DNA<\/strong>, scientists can choose between a number of different methods of analysis.<\/li>\n\n\n\n<li><strong>Short Tandem Repeat (STR) Analysis:<\/strong> Its basis is the short repeating DNA sequences.\n<ul class=\"wp-block-list\">\n<li><strong>STRs are typically found on nuclear DNA<\/strong> which is located within the nucleus of a cell.<\/li>\n\n\n\n<li><strong>Use:<\/strong> High variability among individuals makes STR ideal for identification.<\/li>\n\n\n\n<li><strong>Limitation: <\/strong>Requires well-preserved nuclear DNA.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Mitochondrial DNA (mtDNA) Analysis:<\/strong> Found in mitochondria (outside the nucleus), this method is used when nuclear DNA is degraded or unavailable.\n<ul class=\"wp-block-list\">\n<li>mtDNA is passed down by the mother, unchanged, to all her children. This means that samples from a person\u2019s remains can be matched with the maternal line of inheritance.<\/li>\n\n\n\n<li><strong>Advantage:<\/strong> Easier to recover from degraded samples due to multiple copies per cell.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Y-Chromosome STR Analysis:<\/strong> Analyses STRs on the Y chromosome.\n<ul class=\"wp-block-list\">\n<li><strong>Inheritance: <\/strong>Passed from father to son.<\/li>\n\n\n\n<li><strong>Application: <\/strong>Matches possible with any paternal line male relative (e.g., father, brother, paternal uncle).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Single Nucleotide Polymorphism (SNP) Analysis:<\/strong> It is based on the variation at a single base (A, C, G, T).\n<ul class=\"wp-block-list\">\n<li>It is applied when DNA is highly degraded.<\/li>\n\n\n\n<li><strong>Sources for reference: <\/strong>Victim&#8217;s personal items like toothbrushes or hairbrushes.<\/li>\n\n\n\n<li><strong>Limitation: <\/strong>Less effective than STR analysis.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Conclusion<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>DNA identification is a critical tool in disaster victim identification. Each method has strengths and limitations based on the quality of DNA, type of tissue, and available reference material.&nbsp;<\/li>\n\n\n\n<li>The choice of method depends on the condition of remains and availability of relatives or personal items.<\/li>\n<\/ul>\n\n\n\n<p><strong>Source: <\/strong><a href=\"https:\/\/indianexpress.com\/article\/explained\/explained-sci-tech\/air-india-plane-crash-dna-identification-10067029\/\" rel=\"nofollow noopener\" target=\"_blank\"><strong>IE<\/strong><\/a><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-background has-fixed-layout\" style=\"background-color:#ebecf0\"><tbody><tr><td><strong>Read this in Hindi: <a href=\"https:\/\/www.nextias.com\/ca\/current-affairs-hindi\/16-06-2025\/dna-%e0%a4%aa%e0%a4%b9%e0%a4%9a%e0%a4%be%e0%a4%a8-%e0%a4%95%e0%a5%88%e0%a4%b8%e0%a5%87-%e0%a4%95%e0%a4%be%e0%a4%b0%e0%a5%8d%e0%a4%af-%e0%a4%95%e0%a4%b0%e0%a4%a4%e0%a5%80-%e0%a4%b9%e0%a5%88\">DNA \u092a\u0939\u091a\u093e\u0928 \u0915\u0948\u0938\u0947 \u0915\u093e\u0930\u094d\u092f \u0915\u0930\u0924\u0940 \u0939\u0948?<\/a><\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<h3><strong>Context<\/strong><\/h3>\n<li class=\"ms-5\">After the Air India Boeing 787 Dreamliner crash in Ahmedabad, authorities are using DNA analysis to identify the remains of those killed in the accident.\u00a0<\/li>\n<p><\/p>\n<h3><strong>About<\/strong><\/h3>\n<li class=\"ms-5\">With the exception of identical twins, every person has a unique DNA that is present in nearly every cell of their body.\u00a0<\/li>\n<li class=\"ms-5\">DNA identification is the gold standard for identifying human remains, especially after mass fatality events in which bodies might not be easy to identify otherwise.<\/li>\n<p><a href=\"https:\/\/www.nextias.com\/ca\/current-affairs\/16-06-2025\/how-dna-identification-works\" 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-45541","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\/45541","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=45541"}],"version-history":[{"count":3,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/45541\/revisions"}],"predecessor-version":[{"id":46771,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/posts\/45541\/revisions\/46771"}],"wp:attachment":[{"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/media?parent=45541"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/categories?post=45541"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nextias.com\/ca\/wp-json\/wp\/v2\/tags?post=45541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}