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You are an expert at identifying data availability statements in scientific text. A data availability statement describes where research data can be found or how it can be accessed.<|eot_id|><|start_header_id|>user<|end_header_id|>

Determine if the following text contains a data availability statement. Answer with 'yes' or 'no'.

Text: Vector design for the commercial USERÔ cloning technique involves insertion of a 42 bp cassette which contains two XbaI restriction recognition sites flanked by two Nt . BbvCI nicking recognition sites into the multiple cloning sites ( http://www.neb.com/nebecomm/ManualFiles/manualE5500 . pdf ) . Subsequent digestion of the constructed vector with these two enzymes generates a linearized fragment with 8 nt 3 0 overhangs at each end ( Figure 1 ) . To be applicable with the uracil - based cloning technique , it is required for the restriction enzyme used in the cassette to cut after a thymidine residue in their recognition sequence . This thymidine residue will be the last residue in the 8 nt 3 0 overhangs in the vector and will correspond to the uracil in the PCR primers ( Figure 1 ) . We found that PacI , PmeI , AsiSI and SwaI fulfill this requirement and , in addition , these all have 8 bp recognition sequences which statistically occur less frequently than the 6 bp restriction site of XbaI. We designed a 38 bp cassette that has two PacI sites flanked by two Nt . BbvCI sites at its core ( PacI cassette , Figure 1 , left panel ) . The sequence of the 8 nt 3 0 overhangs generated in USER vectors after digestion is mostly dictated by the recognition sites of the nicking and restriction enzymes used in the cassette . Since the same nicking and restriction recognition sites are used in both halves of the cassette , directional insertion of DNA fragments is ensured by varying the nucleotides lying between the respective recognition sites . In the XbaIcontaining cassette , three variable nucleotides lie between the recognition sites of Nt . BbvCI and XbaI. In our PacI cassette , only one variable nucleotide lies between the Nt . BbvCI and PacI recognition sites ( Figure 1 ) . This could potentially   lower the stringency by which DNA fragments are inserted in a directional fashion . However , we have cloned more than 500 PCR fragments by USER cloning into the described PacI cassette and have not detected a single fragment that has been inserted in the wrong direction ( data not shown ) . Furthermore , calculated T m values for the hybridizing ends of fragments inserted in the correct orientation are 22 C ( 11 ) while the corresponding T m 's for fragments hybridizing in the wrong orientation are close to 0 C. This indicates that the single base difference between the otherwise identical halves of our PacI cassette is sufficient to ensure directional cloning .<|eot_id|><|start_header_id|>assistant<|end_header_id|>

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