Abstract: A quality control system for testing biological samples is provided, comprising: a support having at least one surface capable of receiving one or more predetermined quantities of a biological sample from one or more known donors. A computerized system for testing biological samples is also provided.

Abstract: The invention provides compositions and methods for performing primer extension reactions, including employment of amplification primers having 5? tags to incorporate into amplicons variant nucleotides of interest from target nucleic acids at known ratios, with or without sequences surrounding the variant nucleotides of interest. The invention provides identifying the variant nucleotides generated from the target nucleic acid and generated from the 5? tags, comparing the results, evaluating the efficiency of the primer extension reactions, and monitoring the efficacy of such reactions. The invention accounts for DNA sequence and experimental variables that may affect efficiency of incorporation of nucleotides, and provides a reference point for the interpretation of polymorphisms. The invention also provides methods of breeding scrapie-resistant sheep populations.

Abstract: The present invention provides methods and compositions that reduce target-independent primer extension or enhance template dependent primer extension. The methods and compositions of the present invention are applicable not only in PCR, but also in nucleic acid sequencing, genotyping, and other applications employing extension of a primer in a target-dependent manner.

Abstract: The invention comprises compositions and methods for performing primer extension reactions, including employment of amplification primers having 5? tags to incorporate into amplicons variant nucleotides of interest from target nucleic acids at known ratios, along with the sequences surrounding the variant nucleotides of interest. The invention comprises identifying the variant nucleotides generated from the target nucleic acid and generated from the 5? tags, comparing the results, evaluating the efficiency of the primer extension reactions, and monitoring the efficacy of such reactions. The invention accounts for DNA sequence and experimental variables which may affect efficiency of incorporation of nucleotides, and provides a reference point for the interpretation of polymorphisms.

Abstract: Detection of variable nucleotide(s) is based on primer extension and incorporation of detectable nucleoside triphosphates. By selecting the detection step primers from the region immediately adjacent to the variable nucleotide, this variation can be detected after incorporation of as few as one nucleoside triphosphate. Labelled nucleoside triphosphates matching the variable nucleotide are added and the incorporation of a label into the detection step primer is measured. The selection of the detection step primer is important to the method according to this invention and is dependent on the nucleotide sequence of interest. The detection step primers are preferably selected so as to span the region immediately toward the 3? end from the variable nucleotide to be detected. The detection step primers can also be complementary to a sequence beginning several nucleotides removed from the variable nucleotide.