Monozygotic twins: Identical or distinguishable for science and law?

2021 ◽  
Vol 61 (1_suppl) ◽  
pp. 62-66
Author(s):  
Stefania Turrina ◽  
Elena Bortoletto ◽  
Giacomo Giannini ◽  
Domenico De Leo
Keyword(s):  
Capillary Electrophoresis ◽  
Next Generation Sequencing ◽  
Tandem Repeats ◽  
Massively Parallel Sequencing ◽  
Forensic Genetics ◽  
Monozygotic Twins ◽  
Copy Number Variations ◽  
Next Generation ◽  
Generation Sequencing ◽  
Short Tandem

Monozygotic twins, also known as monovular twins, share an identical genetic heritage because they are two individuals who derive from the same zygote. For this reason, they have been considered indistinguishable. They represent a limit for the application of markers and analytical methods that are routinely used in forensic science because analyses of DNA fragments (short tandem repeats analysed by capillary electrophoresis) are unable to distinguish monozygotic twins. The recent introduction of ultra-deep next generation sequencing in forensic genetics, also known as massively parallel sequencing, has made it possible to identify a number of genetic variations through genome sequencing (such as copy number variations, single nucleotide polymorphisms and DNA methylation) that make it possible to distinguish monozygotic twins. Here, we present a case of ascertaining biological paternity, in which the alleged father had a monozygotic twin brother. This case led to the examination of international law in similar cases in which the only available biological evidence derives from classical forensic genetic analysis, performed with short tandem repeat (autosomal and/or gonosomal) capillary electrophoresis and the probative value, if recognised, of the next generation sequencing technology in the courtroom.

scholarly journals PCR-free library preparation greatly reduces stutter noise at short tandem repeats

2016 ◽  
Author(s):  
Melissa Gymrek
Keyword(s):  
Next Generation Sequencing ◽  
Short Tandem Repeats ◽  
Tandem Repeats ◽  
Repeat Unit ◽  
Library Preparation ◽  
Next Generation ◽  
High Coverage ◽  
Sequencing Technologies ◽  
Generation Sequencing ◽  
Short Tandem

Over the past several decades, the forensic and population genetic communities have increasingly leveraged short tandem repeats (STRs) for a variety of applications. The advent of next-generation sequencing technologies and STR-specific bioninformatic tools has enabled the profiling of hundreds of thousands of STRs across the genome. Nonetheless, these genotypes remain error-prone, hindering their utility in downstream analyses. One of the primary drivers of STR genotyping errors are “stutter” artifacts arising during the PCR amplification step of library preparation that add or delete copies of the repeat unit in observed sequencing reads. Recently, Illumina developed the TruSeq PCR-free library preparation protocol which eliminates the PCR step and theoretically should reduce stutter error. Here, I compare two high coverage whole genome sequencing datasets prepared with and without the PCR-free protocol. I find that this protocol reduces the percent of reads due to stutter by more than four-fold and results in higher confidence STR genotypes. Notably, stutter at homopolymers was decreased by more than 6-fold, making these previously inaccessible loci amenable to STR calling. This technological improvement shows good promise for significantly increasing the feasibility of obtaining high quality STR genotypes from next-generation sequencing technologies.

Next-Generation Sequencing: An Emerging Tool for Drug Designing

2019 ◽  
Vol 25 (31) ◽  
pp. 3350-3357 ◽  
Author(s):  
Pooja Tripathi ◽  
Jyotsna Singh ◽  
Jonathan A. Lal ◽  
Vijay Tripathi
Keyword(s):  
Next Generation Sequencing ◽  
High Throughput ◽  
Large Scale ◽  
Massively Parallel Sequencing ◽  
Genomic Research ◽  
Biological Research ◽  
Next Generation ◽  
Human Welfare ◽  
Drug Designing ◽  
Generation Sequencing

Background: With the outbreak of high throughput next-generation sequencing (NGS), the biological research of drug discovery has been directed towards the oncology and infectious disease therapeutic areas, with extensive use in biopharmaceutical development and vaccine production. Method: In this review, an effort was made to address the basic background of NGS technologies, potential applications of NGS in drug designing. Our purpose is also to provide a brief introduction of various Nextgeneration sequencing techniques. Discussions: The high-throughput methods execute Large-scale Unbiased Sequencing (LUS) which comprises of Massively Parallel Sequencing (MPS) or NGS technologies. The Next geneinvolved necessarily executes Largescale Unbiased Sequencing (LUS) which comprises of MPS or NGS technologies. These are related terms that describe a DNA sequencing technology which has revolutionized genomic research. Using NGS, an entire human genome can be sequenced within a single day. Conclusion: Analysis of NGS data unravels important clues in the quest for the treatment of various lifethreatening diseases and other related scientific problems related to human welfare.

scholarly journals Lavage of the Uterine Cavity for Molecular Detection of Müllerian Duct Carcinomas: A Proof-of-Concept Study

2015 ◽  
Vol 33 (36) ◽  
pp. 4293-4300 ◽  
Author(s):  
Elisabeth Maritschnegg ◽  
Yuxuan Wang ◽  
Nina Pecha ◽  
Reinhard Horvat ◽  
Els Van Nieuwenhuysen ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Tumor Tissue ◽  
Massively Parallel Sequencing ◽  
Uterine Cavity ◽  
Mullerian Duct ◽  
Next Generation ◽  
Benign Lesions ◽  
Cavity Detection ◽  
Müllerian Duct ◽  
Generation Sequencing

Purpose Type II ovarian cancer (OC) and endometrial cancer (EC) are generally diagnosed at an advanced stage, translating into a poor survival rate. There is increasing evidence that Müllerian duct cancers may exfoliate cells. We have established an approach for lavage of the uterine cavity to detect shed cancer cells. Patients and Methods Lavage of the uterine cavity was used to obtain samples from 65 patients, including 30 with OC, five with EC, three with other malignancies, and 27 with benign lesions involving gynecologic organs. These samples, as well as corresponding tumor tissue, were examined for the presence of somatic mutations using massively parallel sequencing (next-generation sequencing) and, in a subset, singleplex analysis. Results The lavage technique could be applied successfully, and sufficient amounts of DNA were obtained in all patients. Mutations, mainly in TP53, were identified in 18 (60%) of 30 lavage samples of patients with OC using next-generation sequencing. Singleplex analysis of mutations previously determined in corresponding tumor tissue led to further identification of six patients. Taken together, in 24 (80%) of 30 patients with OC, specific mutations could be identified. This also included one patient with occult OC. All five analyzed lavage specimens from patients with EC harbored mutations. Eight (29.6%) of 27 patients with benign lesions tested positive for mutations, six (75%) as a result of mutations in the KRAS gene. Conclusion This study proved that tumor cells from ovarian neoplasms are shed and can be collected via lavage of the uterine cavity. Detection of OC and EC and even clinically occult OC was achieved, making it a potential tool of significant promise for early diagnosis.

scholarly journals Comparison of Normalization Methods for Construction of Large, Multiplex Amplicon Pools for Next-Generation Sequencing

2010 ◽  
Vol 76 (12) ◽  
pp. 3863-3868 ◽  
Author(s):  
J. Kirk Harris ◽  
Jason W. Sahl ◽  
Todd A. Castoe ◽  
Brandie D. Wagner ◽  
David D. Pollock ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Massively Parallel Sequencing ◽  
Sequence Data ◽  
Cost Savings ◽  
Massively Parallel ◽  
Next Generation ◽  
Normalization Methods ◽  
The Cost ◽  
Generation Sequencing

ABSTRACT Constructing mixtures of tagged or bar-coded DNAs for sequencing is an important requirement for the efficient use of next-generation sequencers in applications where limited sequence data are required per sample. There are many applications in which next-generation sequencing can be used effectively to sequence large mixed samples; an example is the characterization of microbial communities where ≤1,000 sequences per samples are adequate to address research questions. Thus, it is possible to examine hundreds to thousands of samples per run on massively parallel next-generation sequencers. However, the cost savings for efficient utilization of sequence capacity is realized only if the production and management costs associated with construction of multiplex pools are also scalable. One critical step in multiplex pool construction is the normalization process, whereby equimolar amounts of each amplicon are mixed. Here we compare three approaches (spectroscopy, size-restricted spectroscopy, and quantitative binding) for normalization of large, multiplex amplicon pools for performance and efficiency. We found that the quantitative binding approach was superior and represents an efficient scalable process for construction of very large, multiplex pools with hundreds and perhaps thousands of individual amplicons included. We demonstrate the increased sequence diversity identified with higher throughput. Massively parallel sequencing can dramatically accelerate microbial ecology studies by allowing appropriate replication of sequence acquisition to account for temporal and spatial variations. Further, population studies to examine genetic variation, which require even lower levels of sequencing, should be possible where thousands of individual bar-coded amplicons are examined in parallel.

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