System and method for cleaning noisy genetic data and determining chromosome copy number
Disclosed herein is a system and method for increasing the fidelity of measured genetic data, for making allele calls, and for determining the state of aneuploidy, in one or a small set of cells, or from fragmentary DNA, where a limited quantity of genetic data is available. Poorly or incorrectly measured base pairs, missing alleles and missing regions are reconstructed using expected similarities between the target genome and the genome of genetically related individuals. In accordance with one embodiment, incomplete genetic data from an embryonic cell are reconstructed at a plurality of loci using the more complete genetic data from a larger sample of diploid cells from one or both parents, with or without haploid genetic data from one or both parents. In another embodiment, the chromosome copy number can be determined from the measured genetic data, with or without genetic information from one or both parents.
1. A method for determining genetic data for DNA from a subject, the method comprising:
isolating DNA from a blood sample from the subject, wherein the DNA comprises DNA fragments;
amplifying a plurality of target loci from the DNA fragments to obtain amplification products, wherein adaptors comprising universal amplification sequences are ligated to the ends of the fragmented DNA or DNA derived therefrom, before amplifying the plurality of target loci and wherein the amplifying comprises nested PCR; and
using high throughput genotyping by sequencing by synthesis to detect genetic material from the amplification products and produce genetic data for the plurality of target loci on a chromosome or chromosome segment of interest.
2. The method of claim 1 , wherein the genetic data produced by the high throughput genotyping is noisy and comprises allele drop out errors.
3. The method of claim 1 , wherein the genetic data produced by the high throughput genotyping is noisy and comprises measurement bias.
4. The method of claim 1 , wherein the genetic data produced by the high throughput genotyping is noisy and comprises incorrect measurements.
5. The method of claim 1 , wherein the plurality of target loci comprises SNPs.
6. The method of claim 5 , wherein the confidence that each SNP is correctly called is at least 95%.
7. The method of claim 5 , wherein the confidence that each SNP is correctly called is at least 99%.
8. The method of claim 1 , wherein the plurality of target loci comprises at least 14 SNPs.
9. The method of claim 1 , wherein the plurality of target loci comprises at least 70 SNPs.
10. The method of claim 1 , wherein the plurality of target loci comprises at least 131 SNPs.
11. The method of claim 1 , wherein the plurality of target loci comprises at least 384 SNPs.
12. The method of claim 1 , wherein the plurality of target loci comprises at least 500 SNPs.
13. The method of claim 1 , further comprising normalizing the genetic data for differences in amplification and/or measurement efficiency between the loci.
14. The method of claim 1 , wherein the subject is afflicted with cancer.
15. The method of claim 1 , wherein the subject is suspected of having cancer.
16. The method of claim 1 , wherein the method further comprises after the sequencing:
creating a set of one or more hypotheses specifying genetic data for DNA from the individual;
determining the probability of each of the hypotheses given the produced genetic data; and
using the probabilities associated with each hypothesis to determine the most likely genetic data for DNA from the individual.
17. The method of claim 16 , wherein the probability of each of the hypotheses is determined without use of a reference sample.
18. A method, comprising:
isolating DNA from a blood sample from an individual, wherein the DNA comprises DNA fragments;
amplifying a plurality of target loci from at least some of the DNA fragments to obtain amplification products, wherein the target loci are amplified by amplifying at least some of the DNA fragments with targeted PCR primers and universal PCR primers; and
sequencing a clonal DNA population generated from the amplification products using a next generation sequencing method to detect genetic material from the amplification products and produce genetic data for the plurality of target loci on a chromosome or chromosome segment of interest.
19. The method of claim 18 , wherein the next generation sequencing is sequencing by synthesis.
20. The method of claim 18 , wherein adaptors comprising universal amplification sequences are ligated to the ends of the fragmented DNA or DNA derived therefrom, before amplifying the plurality of target loci.
21. The method of claim 18 , wherein the amplification comprises nested PCR.
22. The method of claim 18 , wherein the individual is afflicted with cancer.
23. The method of claim 18 , wherein the individual is suspected of having cancer.
24. The method of claim 18 , wherein the method further comprises after the sequencing:
creating a set of one or more hypotheses specifying genetic data for DNA from the individual;
determining the probability of each of the hypotheses given the produced genetic data; and
using the probabilities associated with each hypothesis to determine the most likely genetic data for DNA from the individual.
25. The method of claim 24 , wherein the probability of each of the hypotheses is determined without use of a reference sample.
26. The method of claim 18 , wherein the plurality of target loci comprises at least 70 SNPs.
27. The method of claim 18 , wherein the plurality of target loci comprises at least 131 SNPs.
28. The method of claim 18 , wherein the plurality of target loci comprises at least 384 SNPs.
29. The method of claim 18 , wherein the plurality of target loci comprises at least 500 SNPs.