Ajay Kumar Rana

Despite the significant progress of DNA profiling in forensic science, the extraction of DNA from challenging samples remains a formidable obstacle in forensic laboratories. Particularly, hard tissues (bones, teeth, hair, and nails), formalin-fixed tissues, and contaminated samples pose considerable difficulties. DNA extraction from such samples is often complicated, resulting in scanty, degraded, and contaminated DNA. Moreover, the presence of inhibitors from the surrounding environment further hinders DNA quantification and amplification, presenting additional challenges. This review article delves into the molecular basis of these challenges and examines the mechanistic principles underlying standard DNA extraction protocols. To overcome these obstacles, skilled efforts and additional pre-processing techniques are generally required before organic or silica column-based DNA extraction. Such techniques may involve scraping the waste, sample cleaning with detergents, disinfecting, demineralization of bones and teeth, long proteolytic enzyme treatment, in some cases, harsh methods like hot alkali treatment, tailored to the specific sample type. By addressing these challenges and understanding the molecular intricacies involved in DNA extraction, forensic scientists can improve the reliability and success rate of DNA analysis from difficult forensic samples. This review serves as a comprehensive resource for understanding the complexities of DNA extraction and offers potential solutions for recovering the DNA from highly challenging samples.

This case study focuses on identifying a deceased person by establishing paternity and sibship relationships with alleged relatives through unique sharing of alleles. Bone and blood samples from the deceased were provided, along with reference blood samples from an alleged son and an alleged brother. DNA extracted from these samples was quantified, amplified, and analysed using an 8-capillary array DNA analyzer. By an extremely rare coincidence, each amplified autosomal locus in the DNA profiles from both the alleged son and the alleged brother shared at least one allele with the corresponding locus in the DNA profiles from the tissue samples of the deceased. The alleged relationships were further investigated through Y-STR analysis, which confirmed their same immediate patrilineal relationship. To establish the degree of paternity and sibling relationships, we calculated the respective indices and confirmed the relationship to the deceased individual. This is the first case we have encountered where both the son and the brother share autosomal DNA fragments at all amplified loci in the absence of the mother’s reference sample. This forensic study highlights the importance of DNA statistics in determining the strength of relationships based solely on STR results, allowing conclusions to be drawn without further testing as per the alleged relationships.

Forensic laboratories frequently receive cases related to abortion, particularly in the context of paternity disputes and rape crimes. However, the focus has traditionally been on the foetus, while the placenta and its associated components, which start development after one month and mature within three months, are often overlooked. This study represents the comparison of DNA profiling from various parts of the aborted conceptus, including the placenta (foetal side), placenta (maternal side), umbilical cord, and foetus. The results have produced consistent and expected profiles but with meticulous foetal tissue processing. Due to the significant presence of maternal blood in these components, a rigorous washing procedure for the aborted foetal material is imperative before DNA extraction can be carried out. The generated profiles emphasize the equal forensic utility of different conceptus components, challenging the conventional focus on the foetus alone. This study paves the way for collecting and processing of various developed parts of the conceptus for DNA profiling as required by the specific case scenarios.

The constant depletion of wild flora and fauna in India due to uncontrolled human activities, natural habitat destruction and covert poaching activities is threatening the ecological balance. The poaching and trafficking of wild species in the lure of money as well as fashion has wiped out a range of wildlife species that call for critical attention to tackle this menace. There are many transit routes through the states of Uttar Pradesh, Karnataka, West Bengal, Rajasthan, Madhya Pradesh, and Assam, which are major hubs for wildlife trafficking in India, in both domestic and international markets. The poaching of wild animals and plants slowly erases biodiversity, which in turn affects the survival of humans and other living species. Therefore, there is an urgent need to check ongoing wildlife crimes, raise the number of endangered species, rehabilitate exotic/extinct species and restore natural ecosystems. In this article, we collected wildlife crime data from web portals of various stakeholders, government agencies and authentic news sources, and discuss the current crime trends, challenges, and prevention approaches required to control and restore wildlife biodiversity in India.

Y-chromosomal short tandem repeats analysis is commonly used in forensic science to determine paternity, genealogy and number of males in sexual assault cases