2000’s: SNP Arrays
In the early 2000’s, scientists were able to combine thousands of SNP (Single Nucleotide Polymorphism) loci into a single test. SNPs are letter changes in the DNA that can be used as genetic markers for a variety of applications. SNP arrays are not commonly used for relationship testing but are used for a number of other genetic tests including; predisposition to genetic disease, health and wellness, and ancestry. DDC uses a large 800,000 SNP custom array for the GPS Origins™ test. The array contains AIMs (Ancestry Informative Markers), Y-Chromosome markers, mitochondrial markers, ancient DNA markers, and other markers useful for establishing more distant biological relationships like 4th or 5th cousins.
2010’s: Next Generation Sequencing
NGS (Next Generation Sequencing) or Massively Parallel Sequencing is the newest technique available for genetic analysis. This procedure generates a DNA sequence that is the linear arrangement of letters (A, T, C, and G) that occur in a DNA sample. Because the technique allows one to simultaneously start the sequencing at thousands of locations in the DNA that overlap, massive amounts of data can be generated and put back together with appropriate bioinformatics programs. It would be like taking book and cutting out sections of sentences then reassembling the book using a computer program to recognize overlapping sentence fragments.
DDC currently uses NGS for its Non-Invasive Prenatal Paternity Test (NIPP) that can determine the biological father of a fetus as early as 8 weeks gestation using a blood sample from the mother. Before NIPP testing, a chorionic villus sample (cvs) or amniocentesis sample was required from the mother. Both of these procedures are invasive and have a small risk of damage to the fetus. The NIPP test is safe for the fetus and detects circulating cell free fetal DNA (cfDNA) in the mother’s plasma and sequences the DNA to interrogate several thousand SNPs.
DNA Diagnostics Center