Process for controlling contamination of nucleic acid amplification reactions

Claim 2

A process for amplifying nucleic acid, the process comprising: (a) hybridizing an oligonucleotide primer to the nucleic acid; (b) synthesising nucleic acid which incorporates an exo-sample nucleotide from the primer, that is substantially complementary to the nucleic acid; (c) separating the nucleic acid and the synthesised nucleic acid; (d) optionally when required, repeating (a) using the nucleic acid and the synthesised nucleic acid as templates for the primer; and (e) subjecting the synthesised nucleic acid to treatment to render it unable to serve as a template for synthesising further nucleic acid.

Claim 3

A process for preventing or reducing contamination of a second sample comprising nucleic acid by a first sample comprising nucleic acid, the process comprising; (a) incorporating an exo-sample nucleotide into a nucleic acid during amplification of nucleic acid to produce a first sample; (b) when the second sample is suspected of being contaminated by the first sample, subjecting the second sample to treatment to render nucleic acid containing the exo-sample nucleotide substantially unamplifiable.

Claim 4

A process for preventing or reducing contamination of a second sample comprising nucleic acid by a first sample comprising nucleic acid, the process comprising; (a) incorporating an exo-sample nucleotide into a nucleic acid during amplification of nucleic acid to produce a first sample; (b) when the second sample is suspected of being contaminated by the first sample, subjecting the second sample to treatment to render nucleic acid containing the exo-sample nucleotide substantially unamplifiable.

Claim 5

A process for amplifying one or more nucleic acid sequences, the process comprising: (a) incorporating an exo-sample nucleotide into nucleic acid during amplification of a first sample of the nucleic acid sequence(s); and (b) subjecting nucleic acid of a second sample to treatment which renders nucleic acid containing the exo-­sample nucleotide substantially unamplifiable and which does not substantially affect amplification of nucleic acid that does not contain the exo-sample nucleotide; whereby amplified nucleic acid sequences derived from the first sample which contaminate the second sample are not further substantially amplified during amplification of the nucleic acid sequences of the second sample.

Claim 6

A process for amplifying one or more nucleic acid sequences, the process comprising: (a) incorporating an exo-sample nucleotide into nucleic acid during amplification of a first sample of the nucleic acid sequence(s); and (b) subjecting nucleic acid of a second sample to treatment which renders nucleic acid containing the exo-­sample nucleotide substantially unamplifiable and which does not substantially affect amplification of nucleic acid that does not contain the exo-sample nucleotide; whereby amplified nucleic acid sequences derived from the first sample which contaminate the second sample are not further substantially amplified during amplification of the nucleic acid sequences of the second sample.

Claim 7

A process as claimed in any of claims 1 to 3 wherein the exo-sample nucleotide is deoxyuridine.

Claim 8

A process as claimed in any of claims 1 to 4 wherein the treatment is physical, chemical, enzymatic, or biological treatment.

Claim 9

A process as claimed in any of claims 1 to 5 wherein the treatment is treatment with uracil DNA glycosylase.

Claim 10

A process as claimed in any of claims 3 to 6 further comprising: (c) amplifying nucleic acid in the second sample.

Claim 11

A process as claimed in any of claims 1 to 7 further comprising: (d) terminating the treatment in (b), such as by heating.

Claim 12

A process as claimed in any of claims 1 to 8 wherein the amplifying is a process for amplifying at least one specific nucleic acid sequence contained in a nucleic acid or a mixture of nucleic acids wherein each nucleic acid consists of two separate complementary strands, of equal or unequal length, which comprises: (e) treating the strands with two oligonucleotide primers, for each different specific sequence being amplified, under conditions such that for each different sequence being amplified an extension product of each primer is synthesized which is complementary to each nucleic acid strand, wherein the primers are selected so as to be sufficiently complementary to different strands of each specific sequence to hybridize therewith such that the extension product synthesized from one primer, when it is separated from its complement, can serve as a template for synthesis of the extension product of the other primer; (f) separating the primer extension products from the templates on which they were synthesized to produce single-stranded molecules; and (g) treating the single-stranded molecules generated in (f) with the primers from (e) under conditions that a primer extension product is synthesized using each of the single strands produced in (f) as a template.

Claim 13

A process for amplifying one or more nucleic acid sequences, the process comprising: (A) with a first sample containing a nucleic acid sequence or a mixture of nucleic acid sequences, wherein each nucleic acid sequence has two separate complementary strands of equal length: (a) treating the strands with two oligonucleotide primers, for each different specific sequence being amplified, under conditions such that for each different sequence being amplified an extension product of each primer is synthesized which is complementary to each nucleic acid strand and which incorporated an exo-sample nucleotide, wherein the primers are selected so as to be sufficiently complementary to different strands of each specific sequence to hybridize therewith such that the extension product synthesized from one primer, when it is separated from its complement, can serve as a template for synthesis of the extension product of the other primer; (b) separating the primer extension products from the templates on which they were synthesized to produce single-stranded molecules; (c) treating the single-stranded molecules generated from (b) with the primers from (a) under conditions such that a primer extension product is synthesized using each of the single strands produced in (b) as a template; (d) repeating (a) through (c) at least once, thereby amplifying the specific nucleic acid sequence contained by the first sample; and (B) with a second sample containing a nucleic acid sequence or a mixture of nucleic acid sequences, wherein each nucleic acid sequence has two separate complementary strands of equal or unequal length and wherein amplified nucleic acid sequences from (A) may be present in the second sample: (e) subjecting the nucleic acid of the second sample to physical, chemical, enzymatic, or biological treatment which renders nucleic acid containing the exo-sample nucleotide substantially unamplifiable and which does not affect amplification of nucleic acid that does not contain the exo-sample nucleotide; whereby any primer extension products of the first sample, amplified in (A) and present in the second sample, are not further substantially amplified in (B).

Claim 14

A process for amplifying one or more nucleic acid sequences, the process comprising: (A) with a first sample containing a nucleic acid sequence or a mixture of nucleic acid sequences, wherein each nucleic acid sequence has two separate complementary strands of equal length: (a) treating the strands with two oligonucleotide primers, for each different specific sequence being amplified, under conditions such that for each different sequence being amplified an extension product of each primer is synthesized which is complementary to each nucleic acid strand and which incorporated an exo-sample nucleotide, wherein the primers are selected so as to be sufficiently complementary to different strands of each specific sequence to hybridize therewith such that the extension product synthesized from one primer, when it is separated from its complement, can serve as a template for synthesis of the extension product of the other primer; (b) separating the primer extension products from the templates on which they were synthesized to produce single-stranded molecules; (c) treating the single-stranded molecules generated from (b) with the primers from (a) under conditions such that a primer extension product is synthesized using each of the single strands produced in (b) as a template; (d) repeating (a) through (c) at least once, thereby amplifying the specific nucleic acid sequence contained by the first sample; and (B) with a second sample containing a nucleic acid sequence or a mixture of nucleic acid sequences, wherein each nucleic acid sequence has two separate complementary strands of equal or unequal length and wherein amplified nucleic acid sequences from (A) may be present in the second sample: (e) subjecting the nucleic acid of the second sample to physical, chemical, enzymatic, or biological treatment which renders nucleic acid containing the exo-sample nucleotide substantially unamplifiable and which does not affect amplification of nucleic acid that does not contain the exo-sample nucleotide; whereby any primer extension products of the first sample, amplified in (A) and present in the second sample, are not further substantially amplified in (B).