Combinatorial DNA taggants and methods of preparation and use thereof
DNA taggants in which the nucleotide sequences are defined according to combinatorial mathematical principles. Methods of defining nucleotide sequences of the combinatorial DNA taggants, and using such taggants for authentication and tracking and tracing an object or process are also disclosed.
1. A method of making a combinatorial DNA taggant, the method comprising:
a) defining a table of table-mer DNA nucleotide sequences having n columns and q rows, the sequences having a length of t nucleotides, and the table containing n×q table-mers, wherein each table-mer possesses a unique nucleotide sequence and wherein n, q, and t are natural numbers and n and q each have a value greater than 1;
b) defining a library of q n DNA taggants having lengths of n×t nucleotides, wherein each of the DNA taggants is a unique combination of the n×q table-mers;
c) performing a combinatorial analysis to identify a plurality of combinatorial covering DNA strands that simulate a polymerase chain reaction (PCR) response of at least a first one of the DNA taggants of the library wherein sequences of the combinatorial covering strands and primers used in simulating the PCR response are each selected from combinations of the table-mer sequences and their reverse complements; and
d) synthesizing the plurality of combinatorial covering DNA strands as the combinatorial DNA taggant.
2. The method of claim 1 , further comprising performing the combinatorial analysis to identify the plurality of combinatorial covering DNA strands that simulate the polymerase chain reaction responses for the remaining DNA taggants of the library other than the first one of the DNA taggants of the library, and synthesizing the combinatorial covering DNA strands for each of the remaining DNA taggants of the library.
3. The method of claim 1 , wherein performing the combinatorial analysis comprises building a network graph of possible PCR reactions between primer pairs of the table-mer sequences, and analyzing the network graph to identify the plurality of combinatorial covering DNA strands.
4. The method of claim 1 , further comprising representing an alpha-numeric sequence with the combinatorial DNA taggant.
5. The method of claim 4 , wherein the alpha-numeric sequence is a binary sequence.
6. The method of claim 4 , wherein the alpha-numerical sequence is q-ary, where q is greater than 2.
7. The method of claim 1 , further comprising mixing the combinatorial DNA taggant with a non-DNA taggant.
8. The method of claim 1 , wherein the at least one of the plurality of combinatorial covering DNA strands is hybridized to its reverse complement DNA strand.
9. The method of claim 2 , wherein the plurality of combinatorial covering DNA strands are hybridized to their reverse complement DNA strands.
10. The method of claim 3 , wherein building the network graph of possible PCR reactions between primer pairs of the table-mer sequences comprises arranging the n×q table-mers in a substantially circular manner to define a set of n×q nodes, and wherein analyzing the network graph to identify the plurality of combinatorial covering DNA strands comprises drawing lines between the n×q nodes wherein the lines denote all possible n(n−1)q 2 /2 primer pairs of the table-mers.
11. The method of claim 2 , wherein the combinatorial covering DNA strands that simulate the polymerase chain reaction responses for the DNA taggants of the library, including the first of the DNA taggants of the library, are a collection of double-stranded Watson-Crick duplex concatenations of s table-mers selected from the library that yield all of the same positive PCR reactions that exist for the library, wherein s is a natural number and less than n×q.
12. The method of claim 11 , wherein the length of the combinatorial covering DNA strands is n×s nucleotide pairs.
13. The method of claim 11 , wherein the collection of double-stranded Watson-Crick duplex concatenations of s table-mers contains q s strands.