Systems and methods to detect rare mutations and copy number variation
The present disclosure provides a system and method for the detection of rare mutations and copy number variations in cell free polynucleotides. Generally, the systems and methods comprise sample preparation, or the extraction and isolation of cell free polynucleotide sequences from a bodily fluid; subsequent sequencing of cell free polynucleotides by techniques known in the art; and application of bioinformatics tools to detect rare mutations and copy number variations as compared to a reference. The systems and methods also may contain a database or collection of different rare mutations or copy number variation profiles of different diseases, to be used as additional references in aiding detection of rare mutations, copy number variation profiling or general genetic profiling of a disease.
1. A method for preparing and sequencing a population of cell-free deoxyribonucleic acid (cfDNA) molecules, the method comprising:
(a) ligating adaptors comprising molecular barcodes to a plurality of the population of cfDNA molecules to tag at least 20% of the cfDNA molecules in the population of cfDNA molecules, wherein the ligating comprises using more than a 60× molar excess of the adaptors as compared to the population of cfDNA molecules, thereby generating tagged parent polynucleotides;
(b) amplifying a plurality of the tagged parent polynucleotides to generate progeny polynucleotides;
(c) selectively enriching a plurality of the progeny polynucleotides for genomic regions of interest to generate selectively enriched progeny polynucleotides; and
(d) performing high-throughput sequencing to sequence a plurality of the selectively enriched progeny polynucleotides comprising the genomic regions of interest.
2. The method of claim 1 , wherein the population of cfDNA molecules is isolated from a bodily sample.
3. The method of claim 2 , wherein the bodily sample is selected from the group consisting of blood, plasma, serum, urine, saliva, mucosal excretions, sputum, stool, and tears.
4. The method of claim 3 , wherein the bodily sample is obtained or derived from a subject having cancer.
5. The method of claim 1 , wherein the population of cfDNA molecules comprises cfDNA from a diseased cell origin and a healthy cell origin.
6. The method of claim 1 , wherein the ligating is performed using blunt-end or sticky-end ligation.
7. The method of claim 1 , wherein the population comprises 5 to 100 nanograms (ng) of cfDNA molecules.
8. The method of claim 7 , wherein the molecular barcodes are from a set of molecular barcodes comprising 5 to 10,000 different molecular barcode sequences.
9. The method of claim 1 , wherein the molecular barcodes are from a set of molecular barcodes comprising 5 to 1,000 different molecular barcode sequences.
10. The method of claim 9 , wherein the molecular barcodes have a length of 5 to 20 nucleotides.
11. The method of claim 1 , wherein the cfDNA molecules are tagged with n different molecular barcodes, wherein n is at least 2 and no more than 10,000*z, wherein z is a mean of an expected number of duplicate molecules in the population of cfDNA molecules having identical start and stop positions.
12. The method of claim 1 , wherein the ligating comprises using more than an 80× molar excess of the adaptors as compared to the population of cfDNA molecules, and wherein at least 40% of the cfDNA molecules in the population of cfDNA molecules are tagged with adaptors comprising the molecular barcodes.
13. The method of claim 1 , wherein the amplifying in (b) comprises using a universal primer.
14. The method of claim 1 , wherein the selectively enriching comprises performing selective amplification or selective sequence capture.
15. A method for preparing and sequencing a population of cell-free deoxyribonucleic acid (cfDNA) molecules, the method comprising:
(a) ligating adaptors comprising molecular barcodes to a plurality of the population of cfDNA molecules to tag at least 20% of the cfDNA molecules in the population of cfDNA molecules, wherein the ligating comprises using more than a 60× molar excess of the adaptors as compared to the population of cfDNA molecules, thereby generating tagged parent polynucleotides;
(b) amplifying a plurality of the tagged parent polynucleotides using a universal primer to generate progeny polynucleotides;
(c) selectively amplifying a plurality of the progeny polynucleotides for genomic regions of interest to generate selectively amplified progeny polynucleotides; and
(d) performing high-throughput sequencing to sequence a plurality of the selectively amplified progeny polynucleotides comprising the genomic regions of interest.
16. The method of claim 15 , wherein the population of cfDNA molecules is isolated from a bodily sample.
17. The method of claim 16 , wherein the bodily sample is selected from the group consisting of blood, plasma, serum, urine, saliva, mucosal excretions, sputum, stool, and tears.
18. The method of claim 17 , wherein the bodily sample is obtained or derived from a subject having cancer.
19. The method of claim 15 , wherein the population of cfDNA molecules comprises cfDNA from a diseased cell origin and a healthy cell origin.
20. The method of claim 15 , wherein the population of cfDNA molecules comprises DNA from a tumor.
21. The method of claim 15 , wherein the ligating is performed using blunt-end or sticky-end ligation.
22. The method of claim 15 , wherein the population comprises 5 to 100 nanograms (ng) of cfDNA molecules.
23. The method of claim 22 , wherein the molecular barcodes are from a set of molecular barcodes comprising 5 to 10,000 different molecular barcode sequences.
24. The method of claim 15 , wherein the molecular barcodes are from a set of molecular barcodes comprising 5 to 1,000 different molecular barcode sequences.
25. The method of claim 24 , wherein the molecular barcodes have a length of 5 to 20 nucleotides.
26. The method of claim 15 , wherein the cfDNA molecules are tagged with n different molecular barcodes, wherein n is at least 2 and no more than 10,000*z, wherein z is a mean of an expected number of duplicate molecules in the population of cfDNA molecules having identical start and stop positions.
27. The method of claim 15 , wherein the cfDNA molecules are tagged with n different molecular barcodes, wherein n is at least 2 and no more than 100*z, wherein z is a mean of an expected number of duplicate molecules in the population of cfDNA molecules having identical start and stop positions.
28. The method of claim 15 , wherein the ligating comprises using more than an 80× molar excess of the adaptors comprising molecular barcodes as compared to the population of cfDNA molecules, and wherein at least 40% of the cfDNA molecules in the population of cfDNA molecules are tagged with adaptors comprising the molecular barcodes.