Diagnostics and therapeutics
Lois N. Magner, Oliver J. Kim in A History of Medicine, 2017
For diseases that are caused by defective genes, the healer of the future might have to be a genetic engineer rather than an immunologist. In 2000 when leaders of the Human Genome Project announced the completion of working drafts of the complete human genome, Francis Collins, director of the National Human Genome Research Institute, predicted that genomics would revolutionize diagnostics, preventive medicine, and therapeutics. Genetic mapping would be used to improve diagnostic methods, prevent disease, design specific agents to treat patients, and might lead to gene therapy to correct defective genes. Indeed, genetic data have allowed individuals with particular oncogenes (genes associated with hereditary cancers) to undergo preemptive surgical removal of organs at risk of becoming cancerous, including the stomach, breast, ovaries, uterus, colon, and thyroid gland. Another product of the Human Genome Project is the development of forensic genomics. Originally thought of as a way to establish databases for identifying criminals, forensic DNA analysis can also help identify human remains. However, the identification of genetic diseases has progressed much more rapidly than the discovery of therapeutic interventions for such disorders. Screening of newborn babies, therefore, confronts many parents with the heartache of knowing that their baby is affected by a disease that cannot be treated.
Human Skeletal Remains
Cristoforo Pomara, Vittorio Fineschi in Forensic and Clinical Forensic Autopsy, 2020
Forensic anthropology rarely is able to provide an identification, but there are some exceptions (Ubelaker et al. 2019; De Boer et al. 2020). DNA analysis represents the gold standard method to identify subjects. The success of forensic DNA analysis is strictly related to the changes that occur after death (Higgins and Austin, 2013). Generally, to obtain DNA profiling from all the tissue types of the body, the choice is naturally related to the state of preservation (Dettmeyer et al., 2014). The buccal swab or blood sample is usually taken from a recently deceased individual as in living subjects; but DNA analysis could become complex with regard to skeletal remains. Usually, when a corpse is found in an advanced state of decomposition, such as in the case of incomplete skeletonization, samples should be taken from the compact long bones, as well as (preferably intact) teeth, and mitochondrial DNA analysis may have to be performed (Hagelberg et al., 1991; Jeffreys et al., 1992; Draus-Barini et al., 2013).
Identification of the living and the dead
Jason Payne-James, Richard Jones in Simpson's Forensic Medicine, 2019
As forensic DNA analysis continues to progress, identifying, extracting and amplifying smaller and smaller amounts of genetic material, so the risks of contamination from other sources increase. Crime and mass disaster scenes have great potential for cross contamination and standard operating procedures to avoid contamination must always be in place to minimise this risk. Appropriate protective clothing must be worn to prevent the investigators obscuring any relevant DNA by their own material being inadvertently shed from exposed skin, or by sneezing, or perhaps even by touching. In many jurisdictions, it is now a requirement for all those involved in the identification, collection and analysis of samples to provide exclusion DNA samples in the same way as exclusion fingerprints were once provided.
Geolocation prediction from STR genotyping: a pilot study in five geographically distinct global populations
Published in Annals of Human Biology, 2023
Mansi Arora, Hirak Ranjan Dash
The field of forensic DNA analysis is constantly evolving, with rapid technological advancements. Most laboratories use the Capillary Electrophoresis (CE) technique to explore repetitions in Short Tandem Repeat (STR) markers to obtain a unique DNA profile (Butler 2007). However, the use of STR markers has been limited to the purpose of individualisation and it does not provide any additional information regarding investigative leads. In many forensic DNA investigations, sample-limiting conditions can arise, where reference samples are not available for matching (Butler 2015). In such scenarios, the present-day DNA analysis becomes irrelevant, as it fails to provide conclusive identification results. Though database searching for such unknown DNA profiles is an alternative, many developing countries do not have their own databases (Machado and Granja 2020). Some of the potential DNA databases in the world include CODIS, ENFSI STR population database, EMPOP, Family Tree Dna, ENFSI STRbASE, and many more (Ruitberg et al. 2001; Congiu et al. 2012). Hence, it has become imperative to explore the horizon of STR-based DNA profiles to provide investigative leads in cases where reference samples are not available.
Prevalence and characterisation of size and sequence-based microvariant alleles at nine autosomal STR markers in the Central Indian population
Published in Annals of Human Biology, 2021
Hirak Ranjan Dash, Kamayani Vajpayee, Ankit Srivastava, Surajit Das
The current day gold standard of forensic DNA analysis relies on exploring the repeatability of Short Tandem Repeat (STR) markers in human DNA to generate a unique profile. STR loci are found scattered more evenly throughout the genome constituting around 3% of the total genome (Fan and Chu 2007). After completion of the human genome project, ∼700,000 STR loci have been characterised out of which STR loci with two and three nucleotide repeat-units are found to be more prevalent in comparison to tetra-, penta- or hexa- nucleotide STRs (Willems et al. 2014). Despite a huge occurrence of STRs in the human genome, the current recommendation includes only 20 STR markers of either tri- or tetra- nucleotide repeats for forensic DNA analysis (Hares 2015). The well-characterised STR markers with stand-out population-specific forensic and paternity parameters have been included in the list of core loci.
Useful autosomal STR marker sets for forensic and paternity applications in the Central Indian population
Published in Annals of Human Biology, 2021
Hirak Ranjan Dash, Neha Rawat, Kamayani Vajpayee, Pankaj Shrivastava, Surajit Das
Short tandem repeat (STR) markers are the non-coding tandem repeated nucleotide sequences presenting on the human genome. They are highly useful in molecular diagnosis, population studies, linkage analysis, and identity testing, besides their applications in forensics, paternity, and kinship cases (Tilanus 2006; Somanathan and Mathur 2017). Their short size, polymorphic nature, ease of amplification, the development of the multiplex system, and rapid analysis have increased the usefulness of STR markers, and this technology has become an inevitable part of most DNA analysis laboratories (Castella et al. 2013). However, degradation, low copy numbers, and mixed sources pose a huge challenge for forensic DNA analysis using STR markers (Butler 2015a). Though the currently used kits have facilitated the analysis of challenging samples (Mulero and Hennessy 2012), only a core set of STR markers are included in them for analysis of DNA in varied populations throughout the globe (Butler 2007).
Related Knowledge Centers
- Allele
- DNA Profiling
- Polymerase Chain Reaction
- Restriction Fragment Length Polymorphism
- Str Analysis
- Variable Number Tandem Repeat
- DNA Paternity Testing
- Genetic Genealogy
- Gel Electrophoresis of Nucleic Acids
- Locus