How are the cases of disputed paternity solved ? Discuss the recent techniques.

Traditional Methods of Determining Paternity

Before the advent of DNA testing, paternity determination relied heavily on circumstantial evidence and less reliable methods. These methods, while sometimes providing clues, were often subjective and prone to error.

• Family Resemblance: Assessment of physical characteristics to compare the child with potential fathers. This was highly unreliable due to shared traits within families.
• Blood Grouping (ABO System): While initially used, the ABO blood group system proved unreliable. A child can have a blood type different from both parents, which doesn’t necessarily exclude paternity. A child’s blood group must be possible based on the parents’ blood groups.
• Customary Law and Social Norms: In many societies, traditional customs and social structures dictated paternity assignment, which were often based on social standing and power dynamics.

Recent Technological Advancements in Paternity Testing

Modern paternity testing primarily utilizes DNA analysis, offering significantly higher accuracy than traditional methods. These techniques analyze specific genetic markers to determine biological relationships.

DNA Fingerprinting (STR Analysis)

This is the most common method used in paternity testing globally. Short Tandem Repeats (STRs) are highly variable regions of DNA that are inherited from parents.

• Process: DNA is extracted from samples (buccal swabs, blood, hair follicles). STR markers are amplified using Polymerase Chain Reaction (PCR). The resulting fragments are separated and analyzed to determine the individual's genetic profile.
• Probability of Paternity: The probability of paternity is calculated based on the matching STR alleles. A probability of 99.99% or higher typically establishes paternity. A probability of 0% excludes paternity.
• Legal Admissibility: STR analysis is widely accepted as legally admissible evidence in courts worldwide.

Single Nucleotide Polymorphism (SNP) Analysis

SNPs are single-base variations in DNA. While STR analysis focuses on repetitive sequences, SNP analysis examines single nucleotide differences.

• Advantages: SNP analysis can be useful in cases where DNA is degraded or limited (e.g., from old samples or hair shafts with minimal root). It is also used for non-invasive prenatal paternity testing (niPnP).
• niPnP: This technique analyzes fetal DNA circulating in the mother’s blood, allowing for paternity determination without invasive procedures like amniocentesis.

Next-Generation Sequencing (NGS)

NGS technologies offer even greater resolution and can analyze a vast number of genetic markers simultaneously. This can be used for complex cases involving multiple potential fathers or to identify genetic conditions inherited from the father.

Other Techniques

• Mitochondrial DNA (mtDNA) Analysis: Used to determine maternal lineage. While not directly determining paternity, it can provide valuable information in certain cases, especially when the maternal line is in question.
• Y-STR Analysis: Analyzes Y-chromosome STRs, passed down from father to son. Useful in cases involving multiple male relatives.

Legal and Ethical Considerations

While DNA testing provides conclusive evidence, its use raises several legal and ethical concerns.

• Privacy Concerns: Genetic information is highly personal and sensitive. Strict protocols are necessary to protect the privacy of individuals involved.
• Chain of Custody: Maintaining a secure and documented chain of custody for samples is crucial to ensure the integrity of the results and their admissibility in court.
• Consent and Confidentiality: Informed consent from all parties involved is essential. Results are typically confidential and shared only with authorized individuals.
• Admissibility in Court: Legal frameworks govern the admissibility of DNA evidence, ensuring reliability and fairness.
• Impact on Family Dynamics: Paternity testing can have profound emotional and social consequences for families, requiring sensitivity and support.

Case Study: The “Baby M” Case (1988)

The “Baby M” case in New Jersey, USA, highlighted the legal and ethical complexities of paternity testing and surrogacy. The case involved a dispute over custody and paternity of a child born through surrogacy. DNA testing was used to confirm the biological father, leading to significant legal and societal debates about parental rights and the use of assisted reproductive technologies.

Technique	Principle	Advantages	Disadvantages
STR Analysis	Analysis of repetitive DNA sequences	High accuracy, widely accepted	Requires relatively intact DNA
SNP Analysis	Analysis of single nucleotide variations	Useful with degraded DNA, niPnP	Lower discriminatory power than STR analysis

The evolution of paternity determination from traditional methods to advanced DNA-based techniques represents a significant advancement in forensic science and legal proceedings. While STR analysis remains the cornerstone of paternity testing, techniques like SNP analysis and NGS are expanding the possibilities for resolving complex cases. However, the use of these technologies necessitates careful consideration of ethical and legal implications, including privacy, consent, and the potential impact on family dynamics. Continuous refinement of these technologies and robust legal frameworks are crucial to ensure responsible and equitable application of paternity testing in the future.