DNA, or deoxyribonucleic acid, is found in every cell of the body, including skin, blood, teeth, and bones. Each individual inherits 23 chromosomes from each parent, totaling 46 chromosomes. While most DNA sequences are similar across humans, small variations exist. These variations, known as polymorphisms, are crucial for distinguishing one person from another.
DNA polymorphisms refer to the minor differences in DNA sequences that contribute to each person's uniqueness. These variations are essential for identifying individuals and establishing biological relationships, such as paternity or maternity.
Short Tandem Repeats (STRs) are repeating sequences of 2 to 6 DNA base pairs. Individuals vary in the number of times these sequences repeat, making STRs a commonly used form of polymorphism in DNA identification.
Scientists utilize a technique called Polymerase Chain Reaction (PCR) to amplify STR regions from small DNA samples. The process begins with DNA extraction, followed by heating the DNA to separate its strands. Primers and enzymes are then employed to generate multiple identical copies of the STR regions.
A DNA fingerprint is a distinctive pattern of STRs that characterizes an individual. Through a method called capillary electrophoresis, STRs are separated by size, allowing for comparisons among different individuals. Identical twins share the same DNA fingerprint, but all others have unique profiles.
DNA fingerprinting is employed by law enforcement agencies, forensic experts, courts, hospitals, and research institutions. It has even been instrumental in solving cold cases by analyzing preserved evidence.
Even a small sample, such as a drop of blood, a hair root, or saliva, is sufficient for DNA testing.
Yes, DNA can endure for thousands of years. Scientists have successfully analyzed DNA from remains that are up to 65,000 years old, particularly in cold or dry environments.
Sperm and egg cells contain only half of an individual's genetic material, making them vital for tracing lineage and comparing with parental DNA.
“You may never know what results come from your action. But if you do nothing, there will be no result.” – Mahatma Gandhi
Q1. What is the significance of DNA fingerprinting in forensic science?
Answer: DNA fingerprinting plays a crucial role in forensic science by helping to identify suspects and victims in criminal cases through DNA evidence. It provides reliable results that can confirm or exclude individuals based on genetic profiles.
Q2. How can DNA testing establish paternity?
Answer: DNA testing can establish paternity by comparing the child's DNA with that of the alleged father. If the father's DNA matches a significant portion of the child's DNA, it supports the claim of paternity.
Q3. What types of samples can be used for DNA fingerprinting?
Answer: Various samples can be used for DNA fingerprinting, including blood, saliva, hair, and skin cells. Even minute amounts of these samples are sufficient for analysis.
Q4. Why is PCR important in DNA analysis?
Answer: PCR is essential in DNA analysis because it allows scientists to amplify small quantities of DNA, making it easier to study specific regions like STRs for identification and forensic purposes.
Q5. Can DNA from ancient remains be analyzed?
Answer: Yes, DNA from ancient remains can be analyzed, especially if the remains are preserved in favorable conditions. This analysis provides insights into historical populations and lineage.
Question 1: What are Short Tandem Repeats (STRs)?
A) Unique DNA sequences that vary only in length
B) Non-repeating DNA sequences in the genome
C) Repeating sequences of 2-6 DNA base pairs
D) Enzymes used in DNA replication
Correct Answer: C
Question 2: Which technique is used to amplify DNA samples?
A) Gel electrophoresis
B) Polymerase Chain Reaction
C) DNA sequencing
D) Chromatography
Correct Answer: B
Question 3: What is the primary use of DNA fingerprinting?
A) To create genetic maps
B) To identify individuals based on unique DNA patterns
C) To analyze gene expressions
D) To determine blood type
Correct Answer: B
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