Molecular Techniques
Molecular techniques are methods employed in molecular biology, genetics, biochemistry, and biophysics to manipulate and analyze nucleic acids (deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)), protein, and lipids. Techniques in molecular biology are employed to investigate the molecular basis for biological activity. These techniques are used to analyze cellular properties, structures, and chemical reactions, with a focus on how certain molecules regulate cellular reactions and growth.
DNA Fingerprinting and Gel Electrophoresis
The genetic makeup of living organisms is shown by a technique known as DNA fingerprinting. The difference is the satellite region of DNA is shown by this process. Alex Jeffreys has invented the process of DNA fingerprinting in 1985. Any biological samples such as blood, hair, saliva, semen can be used for DNA fingerprinting. DNA fingerprinting is also known as DNA profiling or molecular fingerprinting.
Molecular Markers
A known DNA sequence or gene sequence is present on a chromosome, and it is associated with a specific trait or character. It is mainly used as a genetic marker of the molecular marker. The first genetic map was done in a fruit fly, using genes as the first marker. In two categories, molecular markers are classified, classical marker and a DNA marker. A molecular marker is also known as a genetic marker.
DNA Sequencing
The most important feature of DNA (deoxyribonucleic acid) molecules are nucleotide sequences and the identification of genes and their activities. This the reason why scientists have been working to determine the sequences of pieces of DNA covered under the genomic field. The primary objective of the Human Genome Project was to determine the nucleotide sequence of the entire human nuclear genome. DNA sequencing selectively eliminates the introns leading to only exome sequencing that allows proteins coding.
Describe the principles behind direct and indirect fluorescent antibody
tests.
The principle used in fluorescence microscopy is that fluorescence dyes absorb invisible UV light of shorter wavelength and emits visible longer wavelength green light. So, if microorganisms or tissue cells are stained with a fluorescent dye and examined under microscope with UV light , they are seen as a bright objects.
Fluorescence-staining techniques are of two types-
1. Direct IF
2.Indirect IF
1. Direct IF- In this technique, fluorescein-tagged antibodies are brought in contact with antigens such as bacteria, viruses, which are fixed on a slide. The antigens if present react with antibodies and are observed under fluorescence microscope.
eg, This technique is used for detection of rabies virus.
Disadvantage of this technique is that separate fluorescent conjugates have to be prepared against each antigen to be tested.
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