Methods and compositions for evaluating genetic markers
Aspects of the invention relates to methods and compositions that are useful to reduce bias and increase the reproducibility of multiplex analysis of genetic loci. In some configurations, predetermined preparative steps and/or nucleic acid sequence analysis techniques are used in multiplex analyses for a plurality of genetic loci in a plurality of samples.
1. A method for correcting for errors or bias introduced during nucleic acid analysis workflow, the method comprising the steps of:
obtaining a biological sample comprising a plurality of target nucleic acid molecules from more than one locus of origin;
introducing a set of differentiator tags, wherein members of said set of differentiator tags are associated with members of said plurality, such that one or more of said loci of origin are associated with more than one differentiator tag;
amplifying each of the plurality of tagged target nucleic acid molecules to generate amplicons;
sequencing the amplicons obtained in said amplifying step to obtain sequence reads of each of the amplicons, wherein each of the sequence reads comprises a target nucleic acid molecule sequence and a differentiator tag sequence; and
correcting for error or bias introduced during said workflow by collapsing target:differentiator tag combinations observed more than once into a single count.
2. The method of claim 1 , wherein said correcting step further comprises collapsing all sequence reads comprising a same differentiator tag into a single read before determining a consensus base call for the target nucleic acid molecule sequences.
3. The method of claim 2 , further comprising the step of determining the presence of a sequencing or amplification error based upon a number of said differentiator tag sequences.
4. The method of claim 1 , wherein said biological sample is selected from the group consisting of blood and biopsy tissue.
5. The method of claim 1 , wherein said plurality of target nucleic acid molecules comprises bacterial or viral nucleic acids isolated from said biological sample.
6. The method of claim 1 , wherein said plurality of target nucleic acid molecules are circulating tumor nucleic acid molecules.
7. The method of claim 1 , further comprising the step of determining the copy number of a genomic region or transcript in a patient from whom the sample is obtained.
8. The method of claim 1 , wherein said plurality of target nucleic acid molecules are maternally-circulating fetal or placental nucleic acid molecules.
9. A method for correcting for errors or bias introduced during nucleic acid analysis workflow, the method comprising the steps of:
obtaining a biological sample comprising a plurality of target nucleic acid molecules from more than one locus of origin;
introducing a set of unique differentiator tags, wherein members of said set of unique differentiator tags are randomly associated with members of said plurality of target nucleic acid molecules, such that any given tag is uniquely associated with said locus of origin;
amplifying each of the plurality of tagged target nucleic acid molecules to generate amplicons;
sequencing the amplicons obtained in said amplifying step to obtain sequence reads of each of the amplicons, wherein each of the sequence reads comprises a target nucleic acid molecule sequence and a differentiator tag sequence; and
correcting for error or bias introduced during said workflow by recognizing target/differentiator tags having the same sequence as being derived from the same input molecule.