Whole Genome Sequencing (WGS) and Whole Exome Sequencing (WES) are abbreviated terms for sequencing the entire genome and the entire exome, respectively. In the context of Next-Generation Sequencing (NGS), the term "Panel" represents a "gene package" or a set of targeted genes.
WGS, WES, and Panel each exhibit distinct characteristics in the realm of genomics.
To illustrate, the entire genome sequence comprises approximately 3 gigabases (Gb). If sequencing data amounts to 10 Gb, it can cover the entire genome approximately 3 times, referred to as 3X sequencing depth. In contrast, the coding exons, constituting only 1% of the genome or around 30 megabases (Mb) in size, can achieve sequencing depths of over 100X with 10 Gb of sequencing data. This is even more pronounced for Panels targeting specific genes, where 1 Gb of data can achieve depths of around 1000X. Reduced data volume correlates with lower costs, but one significant advantage of Panels lies in their high sequencing depth.
Consider a wild-type locus with a GG genotype. If a heterozygous mutation occurs, the genotype becomes GT. Sequencing data will simultaneously display sequences containing both G and T, roughly in a 1:1 ratio. In genetic testing, sequencing data is used to infer the true genotype. To confidently conclude a heterozygous mutation at a given locus and prevent interference from sequencing errors, a certain quantity of variant sequences is required, necessitating a minimum sequencing depth, such as 20X.
Due to systematic biases in the sequencing and analysis processes, the distribution of sequences with G and T may not be a perfect 1:1 ratio. Additionally, the sequencing depth at different loci may vary, influenced by factors such as genomic GC content and probe specificity during capture. Higher sequencing depth mitigates these issues, reducing the likelihood of missing variant information in problematic regions.
Moreover, a substantial sequencing depth proves beneficial in identifying mosaic variations. In instances where variations manifest during the fertilization stage, irrespective of the number of cells subjected to sequencing, the variant sequences will each constitute approximately half. On the contrary, variations arising in intermediate developmental stages may exhibit mosaic patterns. The ability to discern lower proportions of mosaicism necessitates increased sequencing depth, making gene Panels particularly adept at this task.
Gene Panels showcase the ability to achieve elevated sequencing depth, conferring an advantageous position in genetic analysis. Moreover, they offer substantial customization flexibility, facilitating the inclusion of pathogenic regions within non-coding domains.
WES, strategically positioned between WGS and Panel sequencing, strikes a harmonious balance by delivering an expanded sequencing scope at a generally acceptable cost. This technology empowers researchers to attain comprehensive sequencing coverage while sustaining a commendable sequencing depth.
WGS stands out for its unparalleled sequencing scope, spanning the entire genome. However, to detect base pair variations, a substantial dataset of approximately 100 gigabases (Gb) is requisite. The current challenges associated with the feasibility and affordability of acquiring such extensive data underscore the considerations for its widespread adoption.
The ongoing debate in the realm of genetic testing revolves around the selection of Panel, WES, or WGS. Each method boasts distinctive advantages, prompting the need for a thoughtful decision-making process.
In cases where testing objectives are clearly defined, the initial preference should be towards Panel sequencing to ensure heightened sensitivity within the designated detection range. Conversely, when testing goals are less defined, considerations should shift towards WES or WGS to uncover a broader spectrum of pathogenic factors. WGS involves sequencing every base pair of the genome, while WES and Panel sequencing employ targeted sequencing techniques.
Ultimately, the decision-making process is contingent upon the clarity of testing objectives. Opting for Panel sequencing guarantees precision in detecting known targets, whereas WES or WGS may be favored when the goal is to explore a wider array of potential pathogenic factors, particularly in scenarios where testing targets lack specificity.
CD Genomics offers ccurate and cost-effective predesigned and custom NGS panel services, which involves capturing DNA fragments from multiple relevant gene target regions using specific gene capture probes. Subsequently, the captured DNA sequences in the target regions are determined using next-generation sequencing (NGS) technology, enabling the identification of target genes and mutation sites.
Targeted RNA sequencing is the optimal choice for studying gene expression and rearrangements, even with samples of poor quality such as FFPE and cfRNA. The probe technology targeting all exonic regions of genes of interest has high coverage, enabling comprehensive gene expression analysis, including subtype analysis of total RNA sequencing.
Exome sequencing panels, as a widely used method in disease research, can rapidly and effectively detect pathogenic gene variations in target genes across the genome. This approach enhances data coverage depth, effectively reducing data analysis time and sequencing costs.
CD Genomics has introduced a probe technology based on bisulfite conversion, enabling methylation analysis of various sample types, such as gDNA and cfDNA. This method accurately analyzes the methylation status of target genes, providing comprehensive methylation results for research. Subsequently, CD Genomics also offers comprehensive bioinformatics analysis services for methylation data.
Accuracy: Based on deep sequencing technology, the accuracy of results exceeds 99%.
Specific Capture: Demonstrates excellent specificity, allowing for chromosome-specific capture in polyploid organisms.
Flexible Customization: Highly adaptable, capable of simultaneously conducting gene sequence detection and targeted mutation detection in a single pipeline.
High Detection Efficiency: Enables parallel sequencing of hundreds of thousands to millions of DNA molecules in a single run, facilitating the simultaneous detection of multiple diseases, numerous genes, and tens of thousands of mutation sites. This ensures rapid, efficient, reliable results with high throughput and cost-effectiveness.