A kind of dna-markeri molecular weight standard and its preparation method and application

Abstract

The invention provides a preparation method of DNA-Marker I molecular weight standard. The preparation method includes: allocating 9 DNAs of different lengths to three plasmids; performing restrictionenzyme digestion with restriction enzyme and then mixing restriction fragments to obtain the DNA-Marker I molecular weight standard. With the method, the problem that the fragments, of DNA Marker, prepared with a DNA restriction enzyme digestion method in the prior art are uneven in brightness is solved, the DNA fragments are identical in brightness by adding copy number of the different DNA fragments and mixing weight ratio of enzyme-digested products of the plasmids, and the problem about unstable quality among batches is solved.

Description

technical field [0001] The invention belongs to the field of biotechnology, and in particular relates to a DNA Marker I molecular weight standard and a preparation method and application thereof. Background technique [0002] DNA molecular weight standard, also known as DNA Marker, is a qualitative or quantitative reference for DNA fragments often used in molecular biology electrophoresis experiments, and generally consists of a series of DNA fragments of different lengths. In agarose electrophoresis, the length and concentration of DNA fragments can be roughly estimated by electrophoresis analysis of DNA Marker and DNA fragments together. [0003] There are generally two methods for the preparation of DNA Markers: DNA fragment mixing method and plasmid restriction enzyme digestion method. [0004] The DNA fragment mixing method is generally formed by mixing single DNA fragments of different lengths. The PCR amplification method is a conventional method to obtain a single ...

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Problems solved by technology

However, there are obvious deficiencies in the method of obtaining DNA fragments by PCR amplification. First, the requirements for production conditions are high. PCR amplification requires not only professional PCR equipment, but also relevant knowledge of molecular biology and primer design. PCR reagents such as Taq enzyme and dNTP also need to be purchased additionally

The second is that the yield of DNA fragments is easily limited. A PCR machine has 96 wells, and the sample volume of each PCR tube is 100 microliters. After the PCR amplification reaction is completed, the volume is about 90 microliters, and only about 8 milliliters can be obtained at most at one time.

The third is that the DNA fragments amplified by PCR are not unique, and are often accompanied by non-specific bands or primer dimers. In order to remove non-specific bands or primer dimers, additional separation and purification steps are required, which not only increases the production cost of DNA Marker , it also appears that the steps are cumbersome

Therefore, the preparation of DNA Marker I by DNA fragment mixing method is not only cumbersome, time-consuming and labor-intensive, but also difficult to standardize the production process, which may easily cause differences in band brightness between different batches of DNA Marker I.

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