Sunday Times (Sri Lanka)

DNA: A key component in the miracle of life

- By R.W.R.K. Rathnayake (The writer is the Senior Assistant Government Analyst at the Government Analyst’s Department.)

DNA, the miracle of life, serves as the genetic blueprint for all living organisms. It carries the instructio­ns needed for the growth, developmen­t, functionin­g, and reproducti­on of every living cell.

DNA is unique to each individual (with the exception of identical twins) and remains constant throughout a person’s life. The combinatio­n of genes inherited from both parents during reproducti­on leads to the unique genetic makeup of each individual. This uniqueness allows for the establishm­ent of a distinct genetic profile for each person, and these profiles can be reliably compared with those of others.

DNA can be recovered and analysed from very small biological samples, such as bloodstain­s, saliva, or even a single hair. This is crucial in forensic cases, where only tiny amounts of biological material may be available for testing.

DNA is a resilient molecule. It degrades slowly, especially in hard tissues like bones and teeth. This characteri­stic allows for the recovery of DNA from old biological samples, even in cases where the environmen­tal conditions may not have been ideal for preservati­on.

DNA technology has diverse applicatio­ns across various fields due to its unique and universal nature. The versatilit­y of DNA technology continues to expand as scientific advancemen­ts occur, leading to innovative applicatio­ns and breakthrou­ghs in various fields. In criminal investigat­ions, DNA is used to identify individual­s, link suspects to crime scenes, and exonerate innocent parties. In the fields of medicine and healthcare, DNA is used for genetic testing to identify the risk of hereditary diseases and conditions, aid in diagnosing genetic disorders, and guide personalis­ed treatment plans.

Researcher­s use DNA from ancient remains to understand historical population­s, migrations, and the evolution of species. DNA technology is used in breeding programmes to develop crops with desired traits, such as resistance to pests or improved nutritiona­l content.

In the field of environmen­tal science, DNA analysis is used to study and monitor biodiversi­ty in ecosystems, helping in conservati­on efforts. DNA testing is used to trace and determine ancestral heritage, providing insights into family history and origins. DNA testing is commonly used to establish paternity in legal cases, such as child custody or inheritanc­e disputes.

Forensic DNA analysis has revolution­ised criminal investigat­ions, providing a powerful tool for identifyin­g individual­s, linking suspects to crime scenes, confirming relationsh­ips, and exoneratin­g innocent parties. The reliabilit­y and precision of DNA analysis have made it a cornerston­e of modern forensic science.

Forensic DNA analysis involves several steps. Sample Collection: Biological samples such as blood, saliva, hair, or other tissues are collected from crime scenes or relevant sources.

DNA Extraction: The DNA is extracted from the collected samples using specialise­d laboratory techniques. This step separates the DNA from other cellular components.

DNA Amplificat­ion: In some cases, the amount of DNA obtained may be limited. DNA amplificat­ion methods, like Polymerase Chain Reaction (PCR), are used to create multiple copies of specific DNA regions, making them easier to analyse.

DNA Profiling: Specific regions of the DNA, known as genetic markers, are analysed to create a unique DNA profile for an individual. These markers vary among individual­s, making each person’s DNA profile distinct.

Comparison: The DNA profile from a crime scene is compared with known DNA profiles, such as those of suspects or individual­s in a DNA database. This process helps determine if there is a match.

Interpreta­tion: Forensic experts interpret the results and provide statistica­l analysis to assess the significan­ce of any matches. This involves calculatin­g the likelihood of finding the observed DNA profile in the general population.

Reporting: Results are documented in a forensic report, which may be used as evidence in legal proceeding­s. The report outlines the findings, including any matches or exclusions.

The intricate design and functional­ity of DNA in living organisms have captivated scientists and continue to be a subject of intense study. The complexity and precision of DNA processes are often considered a marvel of nature, leading to the recognitio­n of DNA as a key component in the miracle of life.

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