Fragment size analysis

Key Words Fragment size analysis capillary electrophoresis genotyping polymorphism polymerase slippage. 

DNA template amounts from 5 to 50 ng from a variety of purification methods have been successfully used in this Fragment Size Analysis protocol. Of primary importance is the uniformity of the concentrations across all samples. This will aid in the uniformity of sample injection, providing higher quality data for downstream analysis. 

CE has been used extensively for fragment size analysis up to several kilobytes (Figure 1) and for DNA sequencing. The dsDNAs after PCR amplification... 

Fig. 6. Physical detection of reciprocal translocations. The chromosomes shown are identical to those in Fig. S. Vertical arrows represent recognition sites for a single restriction enzyme horizontal arrows correspond to synthetic oligonucleotide primers and lines below the chromosomes indicate the sizes of restriction or PCR fragments. In (A), the alteration in restriction fragment size as a result of exchange is illustrated. Such alterations can be detected by Southern analysis using the duplicated sequence as a probe. In (B), the production of a PCR product from one of the exchange chromosomes is illustrated. Neither parental chromosome directs synthesis of a PCR product.

With respect to detection for CE, laser-induced fluorescence (LIF) detection is an attractive approach as a result of the sensitivity attainable despite the short path length. For this reason, it is well suited to microchip electrophoretic analysis of a variety of analytes including DNA fragment sizing and sequencing.The excitation source is usually a continuous-wave argon ion laser, which is focused in a capillary or on a microchannel in a microchip. 

Particle size analysis is useful for assessing attrition because both fragmentation and fine formation yield separate particle populations with different sizes. Production of midsize particles by means of shattering will lower the particle population s mean size and increase its size spread, as formation of fines through surface erosion will make the overall size distribution bimodal or multimodal. Barletta et al. (1993b) summarizes the different size distribution patterns in attrition resulting from the predominant attrition mechanisms and reviews the different models that fit these distributions. 

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