The invention relates to a method for identifying one or more polymorphisms in nucleic acid samples, comprising: (a) performing a reproducible complexity reduction on a plurality of nucleic acid samples to provide a plurality of libraries of the nucleic acid samples comprising amplified fragments, wherein the reproducible complexity reduction comprises amplifying fragments of the nucleic acid samples using one or more primers to obtain the amplified fragments, and wherein the amplified fragments in each library comprise a unique identifier sequence to indicate origin of each library obtained by the reproducible complexity reduction; (b) combining the plurality of libraries to obtain a combined library and sequencing at least a portion of the combined library to obtain sequences; (c) aligning the sequences to obtain an alignment; and (d) identifying one or more polymorphisms in the plurality of nucleic acid samples.

The invention relates to a method for identifying one or more polymorphisms in nucleic acid samples, comprising: (a) performing a reproducible complexity reduction on a plurality of nucleic acid samples to provide a plurality of libraries of the nucleic acid samples comprising amplified fragments, wherein the reproducible complexity reduction comprises amplifying fragments of the nucleic acid samples using one or more primers to obtain the amplified fragments, and wherein the amplified fragments in each library comprise a unique identifier sequence to indicate origin of each library obtained by the reproducible complexity reduction; (b) combining the plurality of libraries to obtain a combined library and sequencing at least a portion of the combined library to obtain sequences; (c) aligning the sequences to obtain an alignment; and (d) identifying one or more polymorphisms in the plurality of nucleic acid samples.

The invention relates to a method for identifying one or more polymorphisms in nucleic acid samples, comprising: (a) performing a reproducible complexity reduction on a plurality of nucleic acid samples to provide a plurality of libraries of the nucleic acid samples comprising amplified fragments, wherein the reproducible complexity reduction comprises amplifying fragments of the nucleic acid samples using one or more primers to obtain the amplified fragments, and wherein the amplified fragments in each library comprise a unique identifier sequence to indicate origin of each library obtained by the reproducible complexity reduction; (b) combining the plurality of libraries to obtain a combined library and sequencing at least a portion of the combined library to obtain sequences; (c) aligning the sequences to obtain an alignment; and (d) identifying one or more polymorphisms in the plurality of nucleic acid samples.

The invention relates to a method for identifying one or more polymorphisms in nucleic acid samples, comprising: (a) performing a reproducible complexity reduction on a plurality of nucleic acid samples to provide a plurality of libraries of the nucleic acid samples comprising amplified fragments, wherein the reproducible complexity reduction comprises amplifying fragments of the nucleic acid samples using one or more primers to obtain the amplified fragments, and wherein the amplified fragments in each library comprise a unique identifier sequence to indicate origin of each library obtained by the reproducible complexity reduction; (b) combining the plurality of libraries to obtain a combined library and sequencing at least a portion of the combined library to obtain sequences; (c) aligning the sequences to obtain an alignment; and (d) identifying one or more polymorphisms in the plurality of nucleic acid samples.

A fractional concentration of clinically-relevant DNA in a mixture of DNA from a biological sample is determined based on amounts of DNA fragments at multiple sizes. For example, the fractional concentration of fetal DNA in maternal plasma or tumor DNA in a patient's plasma can be determined. The size of DNA fragments in a sample is shown to be correlated with a proportion of fetal DNA and a proportion of tumor DNA, respectively. Calibration data points (e.g., as a calibration function) indicate a correspondence between values of a size parameter and the fractional concentration of the clinically-relevant DNA. For a given sample, a first value of a size parameter can be determined from the sizes of DNA fragments in a sample. A comparison of the first value to the calibration data points can provide the estimate of the fractional concentration of the clinically-relevant DNA.

A fractional concentration of clinically-relevant DNA in a mixture of DNA from a biological sample is determined based on amounts of DNA fragments at multiple sizes. For example, the fractional concentration of fetal DNA in maternal plasma or tumor DNA in a patient's plasma can be determined. The size of DNA fragments in a sample is shown to be correlated with a proportion of fetal DNA and a proportion of tumor DNA, respectively. Calibration data points (e.g., as a calibration function) indicate a correspondence between values of a size parameter and the fractional concentration of the clinically-relevant DNA. For a given sample, a first value of a size parameter can be determined from the sizes of DNA fragments in a sample. A comparison of the first value to the calibration data points can provide the estimate of the fractional concentration of the clinically-relevant DNA.

The invention relates to a method for identifying one or more polymorphisms in nucleic acid samples, comprising: (a) performing a reproducible complexity reduction on a plurality of nucleic acid samples to provide a plurality of libraries of the nucleic acid samples comprising amplified fragments, wherein the reproducible complexity reduction comprises amplifying fragments of the nucleic acid samples using one or more primers to obtain the amplified fragments, and wherein the amplified fragments in each library comprise a unique identifier sequence to indicate origin of each library obtained by the reproducible complexity reduction; (b) combining the plurality of libraries to obtain a combined library and sequencing at least a portion of the combined library to obtain sequences; (c) aligning the sequences to obtain an alignment; and (d) identifying one or more polymorphisms in the plurality of nucleic acid samples.

The invention relates to a method for identifying one or more polymorphisms in nucleic acid samples, comprising: (a) performing a reproducible complexity reduction on a plurality of nucleic acid samples to provide a plurality of libraries of the nucleic acid samples comprising amplified fragments, wherein the reproducible complexity reduction comprises amplifying fragments of the nucleic acid samples using one or more primers to obtain the amplified fragments, and wherein the amplified fragments in each library comprise a unique identifier sequence to indicate origin of each library obtained by the reproducible complexity reduction; (b) combining the plurality of libraries to obtain a combined library and sequencing at least a portion of the combined library to obtain sequences; (c) aligning the sequences to obtain an alignment; and (d) identifying one or more polymorphisms in the plurality of nucleic acid samples.

A classification of a level of cancer in an organism is determined by analyzing a biological sample of the organism. The biological sample comprises clinically-relevant DNA and other DNA. At least some of the DNA is cell-free in the biological sample. An amount of a first set of DNA fragments from the biological sample corresponding to each of a plurality of sizes is measured. A first value of a first parameter is calculated based on the amounts of DNA fragments at the plurality of sizes. The first value is compared to a reference value. A classification of a level of cancer in the organism is determined based on the comparison.

A classification of a level of cancer in an organism is determined by analyzing a biological sample of the organism. The biological sample comprises clinically-relevant DNA and other DNA. At least some of the DNA is cell-free in the biological sample. An amount of a first set of DNA fragments from the biological sample corresponding to each of a plurality of sizes is measured. A first value of a first parameter is calculated based on the amounts of DNA fragments at the plurality of sizes. The first value is compared to a reference value. A classification of a level of cancer in the organism is determined based on the comparison.