DNA in the diagnosis of Genetic diseases
Traditional laboratory tests for the diagnosis of genetic diseases are mostly based on the estimation of metabolites and/ or enzymes. This is usually done after the onset of symptoms.
The laboratory test based on DNA analysis can specifically diagnose the inherited diseases at the genetic level. DNA based tests are useful to discover, well in advance , whether the individuals or their offsprings are at risk for any genetic disease. Further, such tests can also be employed for the prenatal diagnosis of hereditary diseases.
By knowing the genetic basis of the diseases, the individuals can be advised on how to limit the transmission of the disease to their offsprings. It may also be possible , in due course of time, to treat genetic diseases by appropriate gene therapies.
Theoretically, it is possible to develop screening tests for all single gene diseases, some of the genetic diseases like cystic fibrosis, sickle-cell anemia, Duchenne's muscular dystrophy, Huntington's disease, Fragile X syndrome, Alzheimer's disease, Amyotrophic lateral sclerosis, Cancers, Diabetes, Deafness, Glaucoma, Baldness, Parkinson's disease, Hemochromatosis, Menke's disease etc.,
A Novel concept of Gene Bank
As the search continues by scientists for the identification of more and more genes responsible for various diseases, the enlightened public, is very keen to enjoy the fruits of this research outcome. As of now, DNA probes are available for a large number of genetically predisposed disorders.
Gene banks are the centres for the storage of individual's DNAs for the future use to diagnose diseases. For this purpose, the DNA isolated from a person's cells( usually white blood cells) is stored. As and when a DNA probe for the detection of a specific disease is available, the stored DNA can be used for the diagnosis or risk assessment of the said genetic disease.
Infact, some institutions have established gene banks. They store the DNA samples of the interested customers at a fee( one firm was charging 200 dollars) for a specific period ( say around 20-25 years). For the risk assessment of any disease, it is advisable to have the DNAs from close relatives of atleast 2-3 generations.
The collection of DNA fragments ( specifically genes) from a particular species represents gene libraries. The creation or construction of gene libraries is accomplished by isolating the complete genome which is cut into fragments , and cloned in suitable vectors. Then the specific clone carrying the desired( target) DNA can be identified, isolated and characterized. In this manner, a library of genes or clones (appropriately considered as gene bank) for an entire genome of a species can be constructed.
Biotechnologists are particularly interested in the isolation of genes which encode for proteins.
Gene banks exist to conserve the genetic diversity of wild and domesticated organisms that humans depend on for food, fiber, medicine and energy.
Over 7 million plant germplasm accessions are housed in 1750 national and international gene banks. Most accessions are poorly characterized; few are ever used.
Gene banks exist to conserve the genetic diversity of wild and domesticated organisms that humans depend on for food, fiber, medicine and energy.
Over 7 million plant germplasm accessions are housed in 1750 national and international gene banks. Most accessions are poorly characterized; few are ever used.
Grand challenges of DNA Bank
- Population and income growth
- Land and water resources
- climate change
- Nutrition, Health, Biosafety
- Sustainability
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