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1.  PlasmaDNA: a free, cross-platform plasmid manipulation program for molecular biology laboratories 
Most molecular biology experiments, and the techniques associated with this field of study, involve a great deal of engineering in the form of molecular cloning. Like all forms of engineering, perfect information about the starting material is crucial for successful completion of design and strategies.
We have generated a program that allows complete in silico simulation of the cloning experiment. Starting with a primary DNA sequence, PlasmaDNA looks for restriction sites, open reading frames, primer annealing sequences, and various common domains. The databases are easily expandable by the user to fit his most common cloning needs. PlasmaDNA can manage and graphically represent multiple sequences at the same time, and keeps in memory the overhangs at the end of the sequences if any. This means that it is possible to virtually digest fragments, to add the digestion products to the project, and to ligate together fragments with compatible ends to generate the new sequences. Polymerase Chain Reaction (PCR) fragments can also be virtually generated using the primer database, automatically adding to the fragments any 5' extra sequences present in the primers.
PlasmaDNA is a program available both on Windows and Apple operating systems, designed to facilitate molecular cloning experiments by building a visual map of the DNA. It then allows the complete planning and simulation of the cloning experiment. It also automatically updates the new sequences generated in the process, which is an important help in practice. The capacity to maintain multiple sequences in the same file can also be used to archive the various steps and strategies involved in the cloning of each construct. The program is freely available for download without charge or restriction.
PMCID: PMC2075515  PMID: 17868482
2.  SiteFind: A software tool for introducing a restriction site as a marker for successful site-directed mutagenesis 
Site-directed mutagenesis is a widely-used technique for introducing mutations into a particular DNA sequence, often with the goal of creating a point mutation in the corresponding amino acid sequence but otherwise leaving the overall sequence undisturbed. However, this method provides no means for verifying its success other than sequencing the putative mutant construct: This can quickly become an expensive method for screening for successful mutations. An alternative to sequencing is to simultaneously introduce a restriction site near the point mutation in manner such that the restriction site has no effect on the translated amino acid sequence. Thus, the novel restriction site can be used as a marker for successful mutation which can be quickly and easily assessed. However, finding a restriction site that does not disturb the corresponding amino acid sequence is a time-consuming task even for experienced researchers. A fast and easy to use computer program is needed for this task.
We wrote a computer program, called SiteFind, to help us design a restriction site within the mutation primers without changing the peptide sequence. Because of the redundancy of genetic code, a given peptide can be encoded by many different DNA sequences. Since the list of possible restriction sites for a given DNA sequence is not always obvious, SiteFind automates this task. The number of possible sequences a computer program must search through increases exponentially as the sequence length increases. SiteFind uses a novel "moving window" algorithm to reduce the number of possible sequences to be searched to a manageable level. The user enters a nucleotide sequence, specifies what amino acid residues should be changed in the mutation, and SiteFind generates a list of possible restriction sites and what nucleotides must be changed to introduce that site. As a demonstration of its use, we successfully generated a single point mutation and a double point mutation in the wild-type sequence for Krüppel-like factor 4, an epithelium-specific transcription factor.
SiteFind is an intuitive, web-based program that enables the user to introduce a novel restriction site into the mutated nucleotide sequence for use as a marker of successful mutation. It is freely available from
PMCID: PMC1314889  PMID: 16321147

Results 1-2 (2)