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Electrophoresis

Fluorescently labeled DNA fragments   DNA fragments pass through a laser beam

Figure 1. Fluorescently labeled DNA fragments move through a capillary.  Figure 2. DNA fragments pass through a laser beam and optical detector.



During capillary electrophoresis, the products of the cycle sequencing reaction are injected electrokinetically into capillaries filled with polymer. High voltage is applied so that the negatively charged DNA fragments move through the polymer in the capillaries toward the positive electrode.

A high voltage is applied so that the negatively charged DNA fragments move through the polymer in the capillaries toward the positive electrode (Figure 1). Capillary electrophoresis can resolve DNA molecules that differ in molecular weight by only one nucleotide.

Shortly before reaching the positive electrode, the fluorescently labeled DNA fragments, separated by size, move through the path of a laser beam. The laser beam causes the dyes on the fragments to fluoresce. An optical detection device on Applied Biosystems DNA analyzers detects the fluorescence (Figure 2).

The Data Collection Software converts the fluorescence signal to digital data, then records the data in a *.ab1 file. Because each dye emits light at a different wavelength when excited by the laser, all four colors, and therefore, all four bases, can be detected and distinguished in one capillary injection.


Capillary Electrophoresis Instrument Selection Guide

 Instrument
 3730xl
3730xL
3730
3730
3500xl
3500xL
3500
3500
3130xl
3130xL
3130
3130
310
310
Number of Capillaries964824
8
24
41
Compatible Applications:
(S) Supported; (A) AB Demonstrated; (C) Customer Demonstrated; (N) Not Supported
BAC End SequencingSSSSSSS
Checking Clone ConstructsSSSSSSS
De Novo Sequencing SSSSSSS
Heterozygote Detection & Resequenicng (SNP-based) SSSSSSA
HLA Typing NNSSSSC
MethylationSSSSSSC
mtDNA Sequencing SSSSSSS
Resequencing
- Comparative GenomicsSSSSSSS
- Indels SSSSSSS
SAGE™ Method CCCCCCA
SNP Analysis SSSSSSS
General Sizing of PCR ProductsSSSSSSS
Fragment Length Polymorphism
- AFLPSSSSSSS
- RFLPAAAAAAA
Large Fragment Analysis
- BAC FingerprintingAAAAAAN
- VNTRCCCCCCC
Microsatellite
- GenotypingSSSSSSS
- Analysis for Forensics/HIDNNSSSSS
- Instability/RERAAAAAAA
Chimerism StudiesCCCCCCC
Conformation Analysis
- SSCPNNAAAAS
Relative Flourescent Quantitation
- Loss of Heterozygosity (LOH)SSSSSSS
SNP Genotyping
- SNaPshot® SystemAASSSSS
- SNPlex™ SystemSSSSSNN
DNA Protein Binding Assays & DNA Fingerprinting CCCCCCC