The research article presents a novel method, Genetic Bit Analysis (GBA), for typing single nucleotide polymorphisms (SNPs) in DNA. Specific fragments of genomic DNA are amplified, rendered single-stranded, captured, and sensed to determine the nature of the resolved nucleotides. Applying this technique, the researchers successfully verified the parentage for thoroughbred horses.
Methodology and Techniques
- Genomic DNA containing the polymorphic sites was amplified using the Polymerase chain reaction (PCR). PCR is a standard molecular biology technique used to make multiple copies of a particular DNA segment from a less quantity. Special primers including a phosphorothioate-modified primer were used. A primer is a short DNA or RNA segment that attaches to the target DNA to start the replication process.
- The molecular technique was implemented to transform the double-stranded amplified DNA into single strands. The T7 gene 6 exonuclease enzyme was used, which selectively digests double-stranded DNA starting from the ends followed by capturing on a plate.
- The capture onto the wells of a plate was done using immobilized oligonucleotide primer. Oligonucleotide primers are small pieces of single-stranded DNA that are designed to bind to the start of the section of DNA to be amplified or studied.
- The extension of the oligonucleotide is carried out using a mixture of labeled and unlabeled dideoxynucleoside triphosphates and either the Klenow fragment of DNA polymerase I or modified T7 DNA polymerase known as Sequenase. Dideoxynucleoside triphosphate is a molecule similar to those used to construct DNA but, when incorporated into a growing DNA chain, it causes chain termination.
- To determine the nature of the extended base, ELISA (enzyme-linked immunosorbent assay), a method used to detect the presence of antibodies in a liquid sample, was implemented using enzymes such as alkaline phosphatase and horseradish peroxidase. These enzymes were conjugated to the antibodies for detection purposes.
Applications of Genetic Bit Analysis (GBA)
- This research utilized the developed GBA method for the task of parentage verification of thoroughbred horses. The process was semi-automated and employed a prior set of 26 diallelic polymorphisms from the equine genome.
- Diallelic polymorphisms represent the simplest form of polymorphisms where there are only two possible alleles, which refer to alternative forms of a gene that arise due to mutation.
- By using the GBA method, the researchers could accurately match offspring to parents based on their genetic information, which is crucial in the practice of breeding horses.
- The successful implementation of GBA in this context implies its potential application in other areas such as human genetic diseases studies, population genetics, and forensic analysis where detecting single nucleotide polymorphisms is critical.