Reaction condition compositions for detecting a genomic variation from a small sample amount from 5 nano grams (ng) to 1 microgram (ug) includes DNA ligase, DNA polymerase, at least one COP, a DNA polymerase buffer, NAD+, at least two primers, and deoxynucleotide triphosphates (dNTPs). Detection of the genomic variation utilizes COPs with increased ligation efficiency and RCA with fluorescence detection due to simultaneous ligation of COPs to CPs and replication of the genomic variation. The reaction condition composition eliminates the need to perform background reduction of un-hybridized or un-ligated COPs.

Methods of assaying cells of a cellular sample for the presence of a target nucleic acid are provided. Aspects of the methods include evaluating a cellular sample that has been contacted with a nuclease inhibitor for the presence of a target nucleic acid. Also provided are devices and kits that find use in practicing the methods described herein.

Methods of assaying cells of a cellular sample for the presence of a target nucleic acid are provided. Aspects of the methods include evaluating a cellular sample that has been contacted with a nuclease inhibitor for the presence of a target nucleic acid. Also provided are devices and kits that find use in practicing the methods described herein.

Disclosed is a method of fragmenting DNA comprising contacting a sample of target DNA with (a) a composition comprising an active transpososome, and (b) a composition comprising an inactive transpososome, under conditions suitable for transpososome activity, wherein a ratio of an amount of the inactive transpososome in the composition of (b) to an amount of the active transpososome in the composition of (a) determines the mean fragment size and a level of insertion bias.

Disclosed is a method of fragmenting DNA comprising contacting a sample of target DNA with (a) a composition comprising an active transpososome, and (b) a composition comprising an inactive transpososome, under conditions suitable for transpososome activity, wherein a ratio of an amount of the inactive transpososome in the composition of (b) to an amount of the active transpososome in the composition of (a) determines the mean fragment size and a level of insertion bias.

A ribonucleic acid (RNA) reverse transcription amplification method, comprising the steps of reverse transcription of RNA into cDNA and immediate amplification of cDNA, characterized in that the process of reverse transcription of RNA into cDNA is completed during the process that a cDNA amplification reaction system is heated to reach the reaction condition for cDNA amplification. The RNA reverse transcription amplification method can combine the reaction condition for reverse transcription of RNA into cDNA with the reaction condition for cDNA amplification, thereby significantly shorten the time required for RNA reverse transcription amplification. And in the whole process of RNA reverse transcription amplification, there is no need to change the instrument temperature, and thus, it is possible to achieve detection at any time.

An apyrase enzyme, characterized by that the apyrase comprises a polypeptide sequence having at least 70% sequence identity to the wild-type Shigella flexneri apyrase of SEQ ID NO:1, wherein said sequence differs from SEQ ID NO:1 at least in that the sequence comprises at least one amino-acid substitution of a residue aligning with a residue selected from: F53, L66 and E77; and the apyrase catalyzes the dephosphorylation of at least one organic phosphate with at least 10-fold lower K.sub.m compared to the apyrase of SEQ ID NO:1. Uses of said apyrase in ATP elimination and dephosphorylation of organic phosphates.

An apyrase enzyme, characterized by that the apyrase comprises a polypeptide sequence having at least 70% sequence identity to the wild-type Shigella flexneri apyrase of SEQ ID NO:1, wherein said sequence differs from SEQ ID NO:1 at least in that the sequence comprises at least one amino-acid substitution of a residue aligning with a residue selected from: F53, L66 and E77; and the apyrase catalyzes the dephosphorylation of at least one organic phosphate with at least 10-fold lower K.sub.m compared to the apyrase of SEQ ID NO:1. Uses of said apyrase in ATP elimination and dephosphorylation of organic phosphates.

Based on the structural features of KIR full genomic sequences, the distribution of single nucleotide polymorphisms in their coding regions and the length of flanking intronic sequence of each exon, a method for high-throughput simultaneous sequence-based typing of all the 14 functional killer cell immunoglobulin-like receptor (KIR) genes is disclosed including: developing a scientific and reasonable polymerase chain reaction (PCR) amplification strategy; simultaneously amplifying the complete coding sequence of each functional KIR gene using 35 pairs of KIR gene-specific PCR primers that have similar annealing temperature; and determining the nucleotide sequences of the exons carried by each PCR amplicon in both directions using the forward and reverse sequencing primers, respectively, as shown in FIG. 1.

The methods of the disclosure can be used to enrich a population of circular polyribonucleotides in a mixture of linear polyribonucleotides, circular polyribonucleotides, and linear polydeoxyribonucleotides.