Abstract: Methods and systems are described herein that include using multiplexed digital amplification reactions to measure the sizes of a plurality of nucleic acid molecules. In various embodiments, the digital amplification reactions use multiple pairs of separate forward and reverse primer pairs to amplify targeted regions of the nucleic acid molecules, where the targeted regions are separated by a specified number of base pairs. In other embodiments, the digital amplification reactions use multiple primer pairs that share a common pair to amplify targeted regions that overlap with one another. The methods and systems are particularly useful for determining the size distributions of the nucleic acid molecules, or classifying a pathology of a subject from whom the nucleic acid molecules are sampled. Advantageously, the methods and systems can measure the sizes of long nucleic acid molecules without relying on inefficient amplification of very long amplicons.

Abstract: Provided herein are compositions comprising tissue-specific markers for identifying a tissue of origin of a cell-free nucleic acid, e.g., a cell-free DNA molecule. Also provided herein are methods, compositions, and systems for identifying a tissue of origin of a cell-free nucleic acid by determining an absolute amount of cell-free nucleic acids comprising the tissue-specific marker. Also provided herein are methods, compositions, and systems for detecting a cancer in a tissue of an organism by analyzing tissue-specific markers.

Abstract: Particular forward and reverse primers may be used to link distant regions of the same large DNA molecule into a smaller DNA molecule. A reverse primer R1 can have a first portion complementary to an ending sequence of region A and can have a second portion having an overlapping sequence. A forward primer F2 can have a first portion complementary to a starting sequence of region B, where the forward primer includes a complementary overlapping sequence (e.g., the same first portion or a second portion) that is complementary to the overlapping sequence. The first portion of F2 may be the entire primer. The smaller DNA molecules can be used to determine haplotypes of regions. Kits including the particular forward and reverse primers are also described.

Abstract: Particular forward and reverse primers may be used to link distant regions of the same large DNA molecule into a smaller DNA molecule. A reverse primer R1 can have a first portion complementary to an ending sequence of region A and can have a second portion having an overlapping sequence. A forward primer F2 can have a first portion complementary to a starting sequence of region B, where the forward primer includes a complementary overlapping sequence (e.g., the same first portion or a second portion) that is complementary to the overlapping sequence. The first portion of F2 may be the entire primer. The smaller DNA molecules can be used to determine haplotypes of regions. Kits including the particular forward and reverse primers are also described.

Abstract: Provided herein are compositions comprising tissue-specific markers for identifying a tissue of origin of a cell-free nucleic acid, e.g., a cell-free DNA molecule. Also provided herein are methods, compositions, and systems for identifying a tissue of origin of a cell-free nucleic acid by determining an absolute amount of cell-free nucleic acids comprising the tissue-specific marker. Also provided herein are methods, compositions, and systems for detecting a cancer in a tissue of an organism by analyzing tissue-specific markers.

Abstract: Particular forward and reverse primers may be used to link distant regions of the same large DNA molecule into a smaller DNA molecule. A reverse primer R1 can have a first portion complementary to an ending sequence of region A and can have a second portion having an overlapping sequence. A forward primer F2 can have a first portion complementary to a starting sequence of region B, where the forward primer includes a complementary overlapping sequence (e.g., the same first portion or a second portion) that is complementary to the overlapping sequence. The first portion of F2 may be the entire primer. The smaller DNA molecules can be used to determine haplotypes of regions. Kits including the particular forward and reverse primers are also described.

Abstract: Particular forward and reverse primers may be used to link distant regions of the same large DNA molecule into a smaller DNA molecule. A reverse primer R1 can have a first portion complementary to an ending sequence of region A and can have a second portion having an overlapping sequence. A forward primer F2 can have a first portion complementary to a starting sequence of region B, where the forward primer includes a complementary overlapping sequence (e.g., the same first portion or a second portion) that is complementary to the overlapping sequence. The first portion of F2 may be the entire primer. The smaller DNA molecules can be used to determine haplotypes of regions. Kits including the particular forward and reverse primers are also described.

Abstract: Provided herein are compositions comprising tissue-specific markers for identifying a tissue of origin of a cell-free nucleic acid, e.g., a cell-free DNA molecule. Also provided herein are methods, compositions, and systems for identifying a tissue of origin of a cell-free nucleic acid by determining an absolute amount of cell-free nucleic acids comprising the tissue-specific marker. Also provided herein are methods, compositions, and systems for detecting a cancer in a tissue of an organism by analyzing tissue-specific markers.