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E Thayer

Publications and source records attributed to E Thayer.

2 recordsLinked to original sources

An algorithmic approach to multiple complete digest mapping.

Multiple Complete Digest (MCD) mapping is a method of determining the locations of restriction sites along a target DNA molecule. The resulting restriction map has many potential applications in DNA sequencing and genetics. In this work, we present a heuristic algorithm for fragment identification, a key step in the process of constructing an MCD map. Given measurements of the restriction fragment sizes from one or more complete digestions of each clone in a clone library covering the molecule to be mapped, the algorithm identifies groups of restriction fragments on different clones that correspond to the same region of the target DNA. Once these groups are correctly determined the desired map can be constructed by solving a system of simple linear inequalities. We demonstrate the effectiveness of our algorithm on real data provided by the Genome Center at the University of Washington.

Algorithms↗

Optimization of restriction fragment DNA mapping.

Consider a mapping project in which overlap of clonal segments is inferred from complete multiple restriction digests. The fragment sizes of the clones are measured with some error, potentially leading to a map with erroneous links. The number of errors in the map depends on the number and types of enzymes used to characterize the clones. The most critical parameter is the decision rule k, or the criterion for declaring clone overlap. Small changes in k may cause an order of magnitude change in the amount of work it takes to build a map of given completion. We observe that the cost of an optimal mapping strategy is approximately proportional to the target size. While this finding is encouraging, considerable effort is nonetheless required: for large-scale sequencing projects with up-front mapping, mapping will be a non-negligible fraction of the total sequencing cost.

Chromosome Mapping↗