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Next: Weak Points Detection Up: Constructing Physical Maps from Previous: Map Quality

   
Main Results

Results presented in this section are for the base scenario, which has the following parameters: Based on the results of 1000 simulations, the algorithm has a probability of $0.039 \pm 0.006$ of making any big errors in the base scenario. The average error in the constructed map is also quite small: $1740 \pm 3 bp.$ The average error can be reduced if a finer quantization unit is used (at a linear cost to memory and CPU consumption). A further experiment indicated a probability of about 0.075 of any mistake that exceeds a clone's length in the estimation of the relative distance between any two (not necessarily adjacent) clones.
  
Figure: True clone order (y axis) vs. constructed order (x axis) in four scenarios. When applicable, weak points shown as vertical dotted lines. The results are taken from the following scenarios: (a) base scenario, (b) a long 2MB genome, (c) a simulation with very low coverage (5), (d) a simulation with very low coverage (5) and very high noise ( $\alpha = 0.3$ and $\beta = 0.25$). Note that all big errors were detected as weak points, though some weak points incorrectly predicted additional big errors. pinpoint possible errors. This information can be used for a judicious choice of additional hybridization experiments, minimizing cost and human effort.

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Figure 10.12: Influence of various simulation parameters on the probability of having big errors. The vertical dotted line indicates the value of the parameter in the base scenario. Note that the effect of a decrease in the number of probes is very similar to that of an increase in the experimental noise. This is because noise decreases the informational content of each probe, an effect that can be countered by an increase in the number of probes. It is also notable that the probe size has a very significant effect, resulting from its direct influence on the frequency of probe occurrences, and therefore on the informational content of the experiment. In contrast, the genome size only moderately effects performance.

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next up previous
Next: Weak Points Detection Up: Constructing Physical Maps from Previous: Map Quality
Itshack Pe`er
1999-03-21