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Genomic research in both research institutesand biotechnology industry hasreceived great attention. During the last 15 years, the Human Genome Project andother major genomic sequencing projects have pushed the fast development of DNAsequencing technology. And the advent of DNA typing in the mid-1980s has also hadan enormous effect on the ability of crime laboratories to identify individuals uniquelyby testing a variety of their body fluids. In the past 20 years, DNA typing forindividual identification has moved at a breathtaking pace. DNA sequencing and DNAtyping, or DNA analyses, are mainly addressed here.
The report has been divided into three chapters.
Chapter 1 provides some basicinformation on DNA structure and function. Then two methods for DNA sequencingare introduced, one is chemical degradation method invented by Maxam and Gilbert,the other is chain termination method invented by Sanger. And the technology ofDNA typing is discussed, especially focused on the 13 commonly used short tandemrepeat (STR) markers in the United States. Finally, the important applications of DNAanalysis are introduced.
Chapter 2 begins with an overview of capillary electrophoresis and laser-excitedfluorescence detection technology. Then the platform of capillary electrophoresisemployed in the experiments is described in detail, it uses a 532nm laser to excite theDNA sample inserted with ethidium bromide. Channel coating and separation matrixloading are also presented here. Lastly, the experimental results of pGEM-3Zf(+)/HaeIII Markers are discussed, which includes the electrophoretograms with 4﹪ LPA and6﹪ LPA, relationship between DNA fragment electrophoresis velocity and strength ofelectric field, relationship between DNA fragment transfer time and sample injectiontime.
Chapter 3 briefly reviews the development of DNA analyzer at first, and thenABI Prism 3100 analyzer is precisely studied. In 3100 analyzer, DNA .samples areprepared in 96- or 384-well plates. After placing on the autosampler, it automaticallymoves the sample plate into position to be sampled by the 16 capillaries. DNAfragments are electrophoretically injected into the capillaries. The DNA fragmentbands are excited by a 488nm laser beam and detected with a CCD camera. Finally, aprototype DNA analyzer of 16 capillaries is introduced. It uses a 90°geometry todetect the laser-excited fluorescence, that is, the incident laser beam and the emittedfluorescence are perpendicular to each other. The analyzer is controlled by an ARMmicrocontroller, LPC2142, after analog to digital conversion, the data is transferred to the computer through USB port.