ApoE-e3 is the most common allele (a variant of the gene) and is found in more than 50% of the general population….According Kerpedjiev, the top-10 most-studied genes are:

• EGFR;
• VEGFA;
• APOE;
• IL6;
• TGFBI;
• MTHFR;
• ESR1; and,
• AKT1.

The chemicals come in four types A, C, T and G. A gene is a section of DNA made up of a sequence of As, Cs, Ts and Gs. Your genes are so tiny you have around 20,000 of them inside every cell in your body! Human genes vary in size from a few hundred bases to over a million bases.

Genes carry the information that determines your traits (say: trates), which are features or characteristics that are passed on to you — or inherited — from your parents. For example, if both of your parents have green eyes, you might inherit the trait for green eyes from them.

Two main strategies have been employed to identify essential genes on a genome-wide basis: directed deletion of genes and random mutagenesis using transposons. In the first case, annotated individual genes (or ORFs) are completely deleted from the genome in a systematic way.

1,282 genes

The problem for the “non-essential”, or conditionally essential genes, is to identify the unknown conditions/circumstances under which the genes are required, because mutants deleted for these genes lack any obvious phenotype under normal conditions.

Background

1. Deletion of a target gene in cells and observation of the resulting phenotype is a common strategy to determine the function of a gene in biological research [1,2,3].
2. The Cre/loxP recombination system is the most commonly used technique to knockout essential genes.

A knockout typically refers to an organism that has been genetically engineered to lack one or more specific genes. Scientists create knockouts (often in mice) so that they can study the impact of the missing genes and learn something about the genes’ function.

The genes can be silenced by siRNA molecules that cause the endonucleatic cleavage of the target mRNA molecules or by miRNA molecules that suppress translation of the mRNA molecule. With the cleavage or translational repression of the mRNA molecules, the genes that form them are rendered essentially inactive.

Knocking out a gene involves inserting CRISPR-Cas9 into a cell using a guide RNA that targets the tool to the gene of interest. There, Cas9 cuts the gene, snipping through both strands of DNA, and the cell’s regular DNA repair mechanism fixes the cut using a process called non-homologous end joining (NHEJ).

To produce knockout mice, researchers use one of two methods to insert artificial DNA into the chromosomes contained in the nuclei of ES cells. Both methods are carried out in vitro, that is in cultured cells grown in laboratory conditions.

4. Application of CRISPR/Cas9 as a Therapeutic Tool for Human Diseases

• 4.1. Monogenic Disorders.
• 4.2. Cystic Fibrosis.
• 4.3. Sickle Cell Anemia.
• 4.4. Thalassemia.
• 4.5. Huntington’s Disease.
• 4.6. Duchenne Muscular Dystrophy.
• 4.7. Hemophilia A.
• 4.8. Chronic Granulomatous Diseases.

Eight Diseases CRISPR Technology Could Cure

• Cancer. One of the most advanced applications of CRISPR technology is cancer.
• Blood disorders.
• Blindness.
• AIDS.
• Cystic fibrosis.
• Muscular dystrophy.
• Huntington’s disease.
• Covid-19.

Gene therapy holds promise for treating a wide range of diseases, such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS.

Scientists have also used CRISPR to detect specific targets, such as DNA from cancer-causing viruses and RNA from cancer cells. Most recently, CRISPR has been put to use as an experimental test to detect the novel coronavirus.

The CRISPR-Cas9 system works similarly in the lab. Researchers create a small piece of RNA with a short “guide” sequence that attaches (binds) to a specific target sequence of DNA in a genome. The RNA also binds to the Cas9 enzyme. Genome editing is of great interest in the prevention and treatment of human diseases.

Kat7 gene inactivation rejuvenates prematurely aging human cells and mice and promotes longevity.

Applications of CRISPR

• Using CRISPR for genome editing.
• Using CRISPR libraries for screening.
• CRISPR/Cas9-mediated chromatin immunoprecipitation.
• Transcriptional activation and repression.
• Epigenetic editing with CRISPR/Cas9.
• Live imaging of DNA/mRNA.
• Therapeutic Applications.

The gene editing tool has been proposed as a way of removing the genetic diseases that abound in pure breed dogs. A great example are Dalmatians, which often carry a genetic mutation that makes them prone to suffer from bladder stones.

Eight Impacts of CRISPR

• Remove malaria from mosquitos. Scientists have created mosquitoes that are resistant to malaria by deleting a segment of mosquito DNA.
• Treating Alzheimer’s disease.
• Treating HIV.
• Develop new drugs.
• Livestock.
• Agricultural crops.
• Develop new cancer treatments.
• Reduce our need for plastic.

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