Illumina Technology

 Genotyping persons using Genomic DNA obtained from the submitted sample is enriched for targeted regions using a hybridization-based protocol, and sequenced using Illumina technology.

Introduction to Genotyping by Sequencing

Genotyping by sequencing, or next-generation genotyping, is a genetic screening method for discovering novel plant and animal SNPs and performing genotyping studies. For some applications, such as genotype screening and genetic mapping, sequence-based genotyping provides a lower-cost alternative to arrays for studying genetic variation.

Various sequence-based genotyping approaches have been developed. Enrichment methods are useful for plants, which often contain duplicated areas of the genome. Restriction enzyme methods are advantageous for species where there is no prior knowledge of the genome.

1. Genomic DNA extraction: The process begins with the extraction of genomic DNA from the submitted sample. This DNA contains the individual's genetic information encoded in their genome.
2. Targeted region enrichment: Rather than sequencing the entire genome, which can be costly and time-consuming, targeted regions of interest are selectively enriched for sequencing. This is typically done using a hybridization-based protocol, where DNA probes complementary to the target regions are hybridized with the genomic DNA sample. This allows specific regions of interest, such as genes or genomic regions associated with particular traits or diseases, to be isolated and enriched for sequencing.
3. Sequencing using Illumina technology: Once the targeted regions are enriched, the enriched DNA sample is sequenced using Illumina sequencing technology. Illumina sequencing is a widely used next-generation sequencing (NGS) method that relies on sequencing-by-synthesis chemistry to generate high-throughput sequencing data. During sequencing, fluorescently labeled nucleotides are incorporated into DNA strands, and the emitted fluorescence is detected and recorded to determine the sequence of bases in the DNA.
4. Data analysis: After sequencing, the resulting data is processed and analyzed to determine the genetic variants present in the targeted regions of the individual's genome. This involves aligning the sequenced reads to a reference genome, identifying genetic variants such as single nucleotide polymorphisms (SNPs) or insertions/deletions (indels), and interpreting their potential functional significance.