What are microsatellites?
Microsatellites, or repetitive DNA, defined as tandem repeats of 1- to 6-mer motifs are pervasive in the human genome – for example, the DNA sequence, CAGCAGCAGCAGCAG, where the motif (CAG) is repeated 5 times. There are approximately one million such repeat-containing loci in the human genome. Microsatellites are mostly known for their role in forensics and paternity testing. About 20 microsatellite loci, which are known to vary among individuals, are measured for all forensics and paternity testing. Orbit Genomics™ explores all one million microsatellite loci.
How are they different from other DNA sequence variations in the human genome?
Most of the genome is non-repeating, and almost all genetic and genomic studies have focused on single nucleotide polymorphisms, called SNPs. These variants, where a single DNA base (or nucleotide) changes, for example a G to an A, are often studied for their role in disease. Although they have been studied extensively, they fall far short of explaining the known or suspected genetic components of disease, especially complex diseases such as cancer, heart or neurological disease. Because of their repeating nature, microsatellites tend to be more susceptible to unstable genomic processes. As a result, they are excellent readouts of genome stability, and are hotspots or causative for certain diseases (Huntington’s Disease, Fragile-X, etc.). Microsatellites are harder to analyze than SNPs and have been largely ignored in studies. They are also present throughout the genome, in both coding and non-coding regions.
How does Orbit Genomics use microsatellites?
Based on over 30 scientific published studies co-authored by our CSO, Skip Garner, Orbit Genomics has developed technologies to accurately measure microsatellite variations and associate those variations with disease. Standard sequencing algorithms, which are optimized for SNPs, do you accurately analyze microsatellites. Orbit Genomics’ OrbiSeq™ technology platform uses proprietary algorithms to accurately call the one million microsatellite loci in the human genome. These advancements have enabled us to develop new diagnostic tools to evaluate risk of certain cancers and for actionable clinical decision support. Orbit Genomics’ analysis pipelines have re-assembled thousands of disease and non-disease (control) genomes to accurately discover small subsets of variants at microsatellite loci, which together form a diagnostic test. Orbit Genomics has also used this technique to compare different traits, for example, responders and non-responders to a given therapy, to develop companion diagnostics for new or established drugs.