PCR stands for polymerase chain Reaction. It will amplify the specific segment of the DNA that makes a million copies of DNA molecule. This technique is widely employed in the areas of molecular biology, research and diagnostic. It has three following steps: This process is carried in a thermocyclerRead more
PCR stands for polymerase chain Reaction. It will amplify the specific segment of the DNA that makes a million copies of DNA molecule. This technique is widely employed in the areas of molecular biology, research and diagnostic.
It has three following steps: This process is carried in a thermocycler, which is a machine that can rapidly heat and cool samples.
Denaturation:
The DNA sample is heated up to (95 deg Celsius), which causes the double stranded DNA separated into single strands.
Annealing:
Primers must be added to the complementary sequence of the targeted DNA fragment. primers are short pieces of single-stranded DNA that are specific for the sequence we want to amplify. In this step, the temperature must be lowered into (50-60 deg C). It allows the primers to anneal or bind to the complementary sequence of the DNA.
Extension:
DNA polymerase enzyme should be added to the DNA fragment so that it will extends the primers, synthesizing a new DNA strand complementary to the target DNA fragment. The temperature is raised into around 72 deg C.
These steps (1-3) are repeated for the many cycles to get the increased amount of the amplified target DNA fragment.
Applications:
DNA cloning:
PCR can be used to create copies of genes or DNA that can be inserted into plasmid or vector for future manipulation.
Genetic testing:
PCR can be used to detect mutations in genes, which can be helpful in diagnosing genetic diseases.
DNA sequencing:
PCR is often used to amplify DNA fragments before they are sequenced.
Forensic science:
PCR can be used to analyze DNA evidence from crime scenes.
COVID-19 testing:
RT-PCR is the most common type of test used to diagnose COVID-19. It detects the presence of viral RNA in a patient’s respiratory sample.
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The first genetically engineered (GE) crop in India was Bt cotton, introduced in 2002. Bt cotton is a genetically modified organism (GMO) that contains genes from the bacterium Bacillus thuringiensis (Bt). These genes produce proteins that are toxic to specific insect pests, particularly the bollworRead more
The first genetically engineered (GE) crop in India was Bt cotton, introduced in 2002. Bt cotton is a genetically modified organism (GMO) that contains genes from the bacterium Bacillus thuringiensis (Bt). These genes produce proteins that are toxic to specific insect pests, particularly the bollworm, which is a major pest affecting cotton crops.
Production of Bt Cotton
The production of Bt cotton involved the following steps:
Pros of Bt Cotton
Cons of Bt Cotton
- Development of Resistance: Over time, target pests can develop resistance to the Bt toxin, rendering the technology less effective.
- Impact on Non-Target Organisms: There are concerns about the impact of Bt toxin on non-target organisms, although studies on this have shown mixed results.
- Biodiversity: The widespread adoption of Bt cotton may reduce agricultural biodiversity.
- Cost of Seeds: Bt cotton seeds are often more expensive than conventional seeds, which can be a burden for small-scale farmers.
- Regulatory and Ethical Concerns: There are ongoing debates about the safety and ethics of genetically modified crops, including concerns about long-term health effects and corporate control over seed supplies
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