The present disclosure relates in some aspects to methods for analyzing a target nucleic acid in a biological sample. In some aspects, provided herein are methods and compositions for detecting a region of interest in a target nucleic acid, wherein hybridization between an interrogatory region of a probe and a region of interest of the target nucleic acid is blocked by a blocking strand unless the interrogatory region is complementary to the region of interest. In some aspects, the methods provided herein increase specificity of detecting a region of interest in a target nucleic acid (e.g., a SNP in an RNA molecule). In some aspects, the presence, amount, and/or identity of a region of interest in a target nucleic acid is analyzed in situ. Also provided are polynucleotides, sets of polynucleotides, compositions, and kits for use in accordance with the methods, for example for RNA-targeting padlock probe-mediated SNP detection.

The present disclosure relates in some aspects to methods and compositions for analysis of a target nucleic acid, such as in situ detection of a region of interest in a polynucleotide in a tissue sample. In some embodiments, provided herein are templated ligation probes (e.g., RNA-templated ligation probes) and selector probes for generation of a circularized ligated probe comprising an insertion sequence of a selector probe, wherein the circularized ligated probe is amplified in a rolling circle amplification reaction to generate a product that is detected in the sample.

The present disclosure relates in some aspects to methods and compositions for analysis of a target nucleic acid, such as in situ detection of a region of interest in a polynucleotide in a tissue sample. In some embodiments, provided herein are templated ligation probes (e.g., RNA-templated ligation probes) and selector probes for generation of a circularized ligated probe comprising an insertion sequence of a selector probe, wherein the circularized ligated probe is amplified in a rolling circle amplification reaction to generate a product that is detected in the sample.

A method for determining sequences from sense and antisense strands of a nucleic acid, including (a) providing a nucleic acid cluster attached to a solid support, wherein the nucleic acid cluster includes a sense strand and an antisense strand of a concatemer, the concatemer including multiple copies of a sequence unit, the sequence unit including a target sequence and a primer binding site; (b) hybridizing a primer to a primer binding site in the antisense strand; (c) extending the primer along the antisense strand to determine the sequence from at least a portion of the target sequence in the antisense strand; (d) hybridizing a second primer to a primer binding site in the sense strand; and (e) extending the second primer along the sense strand to determine the sequence from at least a portion of the target sequence in the sense strand.

A method for determining sequences from sense and antisense strands of a nucleic acid, including (a) providing a nucleic acid cluster attached to a solid support, wherein the nucleic acid cluster includes a sense strand and an antisense strand of a concatemer, the concatemer including multiple copies of a sequence unit, the sequence unit including a target sequence and a primer binding site; (b) hybridizing a primer to a primer binding site in the antisense strand; (c) extending the primer along the antisense strand to determine the sequence from at least a portion of the target sequence in the antisense strand; (d) hybridizing a second primer to a primer binding site in the sense strand; and (e) extending the second primer along the sense strand to determine the sequence from at least a portion of the target sequence in the sense strand.

The present disclosure belongs to the technical field of pathogen detection, in particular to loop-mediated isothermal amplification (LAMP) primer sets for detecting porcine susceptibility-related pathogenic bacteria, and a kit, a LAMP chip and use based on the same. The LAMP primer sets for detecting porcine susceptibility-related pathogenic bacteria include an Actinobacillus pleuropneumoniae primer set, a Haemophilus parasuis primer set, a Salmonella choleraesuis primer set, a Bordetella bronchiseptica primer set, a Pasteurella multocida primer set, a Streptococcus suis primer set, and an Erysipelothrix rhusiopathiae primer set.

The present disclosure belongs to the technical field of pathogen detection, in particular to loop-mediated isothermal amplification (LAMP) primer sets for detecting porcine susceptibility-related pathogenic bacteria, and a kit, a LAMP chip and use based on the same. The LAMP primer sets for detecting porcine susceptibility-related pathogenic bacteria include an Actinobacillus pleuropneumoniae primer set, a Haemophilus parasuis primer set, a Salmonella choleraesuis primer set, a Bordetella bronchiseptica primer set, a Pasteurella multocida primer set, a Streptococcus suis primer set, and an Erysipelothrix rhusiopathiae primer set.

A method for determining sequences from sense and antisense strands of a nucleic acid, including (a) providing a nucleic acid cluster attached to a solid support, wherein the nucleic acid cluster includes a sense strand and an antisense strand of a concatemer, the concatemer including multiple copies of a sequence unit, the sequence unit including a target sequence and a primer binding site; (b) hybridizing a primer to a primer binding site in the antisense strand; (c) extending the primer along the antisense strand to determine the sequence from at least a portion of the target sequence in the antisense strand; (d) hybridizing a second primer to a primer binding site in the sense strand; and (e) extending the second primer along the sense strand to determine the sequence from at least a portion of the target sequence in the sense strand.

A method for determining sequences from sense and antisense strands of a nucleic acid, including (a) providing a nucleic acid cluster attached to a solid support, wherein the nucleic acid cluster includes a sense strand and an antisense strand of a concatemer, the concatemer including multiple copies of a sequence unit, the sequence unit including a target sequence and a primer binding site; (b) hybridizing a primer to a primer binding site in the antisense strand; (c) extending the primer along the antisense strand to determine the sequence from at least a portion of the target sequence in the antisense strand; (d) hybridizing a second primer to a primer binding site in the sense strand; and (e) extending the second primer along the sense strand to determine the sequence from at least a portion of the target sequence in the sense strand.

Provided herein are methods for enriching a biological sample for a target nucleic acid, and analyzing the nucleic acid. In some cases, a biological sample is enriched for target nucleic acids associated with a cancer or tumor. In some cases, a biological sample is enriched for target nucleic acids, and the target nucleic acids vary in length. In some cases, one or more probes are used to enrich the biological sample for the target nucleic acid. In some cases, one or more probes hybridize to one or more ends of a target nucleic acid.