Agarose gel electrophoresis identifies DNA

related topics"
Objective

the principles and methods of
agar
sugar gel electrophoresis identification
DNA
through experiments.
Experimental PrincipleAgarose is a hybrid polysaccharide extracted from seaweed and is a line-like high-polypolymer formed by D-type and L-type semi-lactose connected by α-1, 3 and β-1,4 glycoside bonds (shown in the figure below). Agarose expands in cold water, dissolves in hot water into a sol, cools and becomes a gel with aperture ranges from 50nm to greater than 200nm.
agarose
gel electrophoresis
is one of the most commonly used methods for separating, identifying and purifying DNA fragments. Agarose can also be poured into various shapes, sizes and apertures, electrophoresis in different devices, and, if necessary, dna bands can be recovered from the gel.
a wide range of agarose gels, with different gel concentrations and devices selected, from 50 base pairs to several trillion different lengths of DNA can be isolated. The electrophoresis method of horizontal plate agarose gel electrophoresis with constant electrophoresis strength and electrophoresis direction can be used to separate DNA fragments at a length of 50-20,000 bp.The migration rate of DNA in agarose gels is affected by a variety of factors. For example
the
of the dna, the concentration of agarose, the voltage added, and so on. The longer the DNA fragment, the slower the swim speed, and the speed of the swim is directly related to the intensity of the electric field. A linear DNA fragment of a given size has different migration rates in different concentrations of agarose gels, and the pair of DNA electrophoresis migration rates is linearly related to the gel concentration.
with low concentrations of fluorescent dyes such as ethyl bromide, DNA in the gel can be detected directly. 20pg of double-stranded DNA can be detected directly under UV lamps.

1. Experimental equipment
horizontal plate electrophoresis tank; irrigation mold and comb; electrophoresis instrument; 55 degrees C water bath; boiling water bath
micro
2. Experiment
Reagent
(1) DNA samples; DNA standard molecular weight markers; agar sugar; 1x electrophoretic buffer TBE; 6x sample buffer
(2) ethyl bromide ingots: ethyl bromide added to water, stirred for several hours to dissolve. The matching 10 mg/ml of ethyl bromide solution is packed in a brown bottle, stored at room temperature and diluted to 0.5 mg/ml when used.
the buffer solution is used to makeBuffer solutionworking solutionstorage solution (per liter) TBE 0.5x 5x 0.045mol/L Tris-boric acid 54 g Tris alkali 0.001mol/L
EDTA27.5g boric acid 20ml 0.5mol/L EDTA (pH8.0) 6x sample buffer 0.2% bromophenol bluestorage temperature 4c 50% (w/v) sucrose water