A marker is used in a procedure called marker assisted selection, or MAS. Indirect selection of a genetic determinant or determinants of an interest characteristic, such as productivity, disease resistance, abiotic stress tolerance, and quality, is carried out using a marker. Breeding of both plants and animals uses this mechanism. Basically, there are four different types of these markers: morphological, biochemical, cytological, DNA-based, and molecular-based markers. Marker-assisted selection is now used by plant breeders (MAS). The markers are a piece of DNA made up of a string or sequence of nucleic acids. With the development of molecular genetics, the genes responsible for nearly half of the 7,000 Mendelian hereditary disorders that are thought to exist were discovered. For the patient's proper medical care and the family's genetic counselling, it is more crucial than ever to confirm the diagnosis through genetic testing. A more limited selection of genetic testing are accessible, though, in standard clinical practise. The most common tests are a select few and are simple to commercialise because the diseases either have a low incidence or testing is straightforward due to an existing mutational hot spot or a single mutational mechanism that causes the disease. On the other side, there is a lack of genetic testing for rare diseases such malformation syndromes and hereditary skeletal disorders. The genes that cause these disorders usually have enormous sizes and a wide mutational spectrum due to allelic and locus heterogeneity. Because entire coding exon sequencing is currently the gold standard approach for genetic testing, molecular diagnoses of these diseases are therefore labor-intensive and expensive to produce.

For instance, GENDIA offers more than 2,000 different tests, including those for these uncommon disorders, with prices ranging from 1,000 on average to 4,000, depending on the size and quantity of the genes. Patients are responsible for the expense and hardly ever have these tests covered by insurance. There are two ways to make these orphan disease genetic tests available to the broader population. Establishing a central testing laboratory and gathering samples from all throughout the nation is one method. The mutation of a single big gene or a set of genes that produce related diseases has recently been screened using next generation sequencing (NGS), which is a newer technology. NGS is a promising and intriguing method in the near future if enough samples are collected all at once, as pooling samples reduces the operating cost per sample. Another method is for the neighbourhood hospitals to offer in-house molecular testing at a discount to meet local demands. We recently created the CHIPS (CEL Nuclease Mediated Heteroduplex Incision with Polyacrylamide Gel Electrophoresis and Silver Staining) technology to address this issue. This technology uses an enzyme mismatch cleavage method that has been meticulously optimised at every stage to achieve the highest levels of sensitivity and ease.

Using only readily accessible commercial reagents and simple equipment, CHIPS achieves nearly 100% sensitivity of mutation detection. In addition, CHIPS provides economical, simple mutation screening by eliminating 90–95% of the expense and labour associated with direct sequencing. These two approaches are not meant to be mutually exclusive; rather, they should be used in both the medical and social contexts. All Japanese citizens are required to enrol in the government's system of universal health insurance coverage. The Japanese people are fortunate to have this insurance system in place for their access to basic medical care. However, this insurance does not cover the majority of modern medical technology, including genetic testing.