METHOD AND SYSTEM FOR PRODUCEING A UNIQUE IDENTIFIER OF A SUBJECT FROM THE SUBJECT'S DNA

Description

GENERAL TECHNICAL FIELD

[0001] The invention relates to the field of biometric authentication and more particularly to the generation of a unique identifier of a subject from their DNA. STATE OF THE ART

[0002] The issues surrounding the concept of identity are significant and cover a wide range of areas, from administrative needs (nationality, voting rights, health, retirement, etc.) to national security requirements (borders, crime, victims, missing persons), including the protection of property and data (banking, medical information, etc.). These issues imply a guarantee of individual identity.

[0003] The use of individuals' biometric traits is therefore of interest.

[0004] To authenticate individuals, several methods based on one or more biometric traits have been implemented.

[0005] In India, for example, a population identification system has been put in place which allows a national identification number to be assigned to each individual based on their fingerprints or a photograph of their iris.

[0006] We also know of voting systems that use fingerprint recognition to identify voters.

[0007] ZHAOSHUZENG ET AL: "Evaluation of 96 SNPs in 14 Populations for Worldwide Individual Identification* describes a method for generating an identifier from a DNA sample from which are selected those whose allele frequency is greater than or equal to 30% on the minor allele) and describes that it should be greater than or equal to 35%.

[0008] However, the use of these biometric traits is not without its problems: Identification based on these traits is no longer possible once the observed biometric trait is altered (aging, cosmetic surgery, accident). These traits are often modified during childhood, making it difficult to identify an adolescent / adult based on traits measured at birth or early childhood. Measurements of these traits may not be completely reliable; the holder of the biometric trait may be endangered in the event of an attempt to steal it; and it is not possible to change one's identifier. PRESENTATION OF THE INVENTION

[0009] The invention proposes to overcome at least one of the drawbacks by offering a means of identifying individuals efficiently and uniquely while guaranteeing both the security and the privacy of individuals.

[0010] To this end, the invention proposes a method for generating a unique identifier for a subject from a genotyped DNA sample of said subject, the method comprising the steps of: obtaining a number of genomic positions of interest, said genomic positions obtained being such that on a population of M subjects, these genomic positions exhibit a binary polymorphism having an allelic frequency of 29% ±7% for the minority allele; combining two by two the genomic positions obtained by means of logical functions so as to obtain a binary code cb.

[0011] The invention is advantageously complemented by the following features, taken alone or in any technically feasible combination thereof: The allele frequency is 29%; the polymorphism comprises a single nucleotide polymorphism (SNP); the pairwise combined positions are unlinked and are preferentially separated by at least 100 centimorgans or on different chromosomes; the polymorphism is an insertion or deletion of at least two nucleotides; the combination consists of comparing the genomic positions of interest as follows: the positions obtained are Pi, i=1 to N; logical states '1' or '0' are assigned as follows: Pi='1' if at least one allele 1 is present in the two SNPi variations, otherwise Pi='0'; pairwise logical combination of the Pis to obtain the binary code cb; the positions obtained are non-coding for the subject and at the very least do not include information about the sex of said subject; the process includes a step of encrypting the binary code obtained, the encrypted code also being binary;The process includes a step of converting the resulting binary code into a hexadecimal code or a QR code.

[0012] The invention relates to a system for generating a unique identifier of a subject from a genotyped DNA sample of said subject, comprising a processor configured to implement a method according to the invention.

[0013] The invention has numerous advantages.

[0014] The invention is based on DNA, which is available in an identical manner in any part of the human body (except for somatic mutations).

[0015] The generated identifier is: unique for each individual, anonymous, and stable over time; in particular, it does not degrade and is tamper-proof. Furthermore, storing the identifier is simple because it does not require much space, unlike storing an individual's raw genetic information.

[0016] The invention thus makes it possible to generate a unique identifier for each subject (with the exception of identical twins or clones). This identifier is based on the genetic diversity of the species studied worldwide. Knowledge of this diversity allows for the specific selection of genomic positions and the mathematical calculation of the probability that subjects possess the same identifier. It is therefore possible to demonstrate that a hundred suitably chosen positions will suffice to make this probability zero. The method proposed here is based on the concept of a pair of positions. Indeed, using two positions (i.e., a pair of positions), the probability that two randomly selected subjects share the same code is 1 / 2. The corresponding general formula is 0.5<n>, where n is the number of pairs of positions studied. Thus, 100 positions studied correspond to 50 pairs, resulting in a probability of 0.5<50> or 10-15.

[0017] The identifier itself is anonymous in that it is impossible to obtain any information about the person (age, place of birth, sex, region of origin, physical characteristics, genomic characteristics). In other words, a person's identifier provides no information that could potentially help to characterize them in any way. Due to its design and the characteristics of the genetic markers, it is impossible to obtain information about the genome used from the identifier, even for those who possess the algorithm used to generate the identifier.

[0018] The invention makes it possible to obtain a fundamentally different identifier between two subjects, whether they are chosen at random or belong to the same family. Belonging to the same population has no influence on the identifier. For example, for two identifiers composed of 20 hexadecimal digits, the probability that two subjects share the same identifier is less than 1 in 72 quadrillion.

[0019] DNA analysis of an individual will always yield the same unforgeable and timeless identifier. The identifier is therefore timeless. Thus, from birth to death, an individual will always have the same genome (and consequently, the same identifier). Since DNA is well preserved post-mortem, it is possible to verify an individual's identifier long after their death (it is even possible to generate the identifier of an individual who died 40,000 years ago).

[0020] Advantageously, the final identifier is a hexadecimal code that can be easily read and allows instant identification with computer means by comparing it to a register containing several million or even billions of numbers.

[0021] The applications of the invention are numerous.

[0022] It is possible to use the same methodology outlined here to create different types of identifiers (one identifier specific to legal applications, another for banking applications, etc.) for a subject (by changing, for example, the positions chosen).

[0023] The identifier helps to address authentication and banking secrecy issues, the invention allowing independent identifiers to be generated for each application.

[0024] This identifier can allow forensic police to identify an individual.

[0025] This identifier allows, for example, opening a bank account. Thus, only the person whose genome matches the identifier can access the account's contents.

[0026] This identifier allows, for example, opening an account to store personal documents (property, identification) or money for oneself or one's children, with a guarantee that the beneficiary can access it in the future. This is particularly useful in the event of a catastrophic event such as the loss of identification documents or other usual means of identification (flood, fire, war, sudden death of two parents, etc.). PRESENTATION OF THE FIGURES

[0027] Other features, purposes and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which: there figure 1illustrates a system for generating an identifier according to one embodiment of the invention; the figure 2 illustrates a method for generating an identifier according to one embodiment of the invention; The figure 3 illustrates data on sequences implemented in the invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] In relation to the figure 1 A system 1 for generating a subject's identifier from a DNA sample of said subject comprises a processing unit 10 (for example, a processor) configured to implement a method for generating an identifier from a DNA sample described below in relation to the figure 2 .

[0029] The subject or individual can be any entity composed of DNA (a human being, an animal, a plant, etc.).

[0030] In a preliminary step (step E0), at least one DNA sample (DNA1, DNA2, DNA3) is taken from a subject. Preferably, samples are taken from several different locations (three different locations, for example). The sample could be saliva, blood, hair, etc., or more generally, anything that allows for the collection of various types of biological samples containing cells from the individual.

[0031] From the samples taken, the subject's DNA is sequenced / genotyped (step E1).

[0032] Sequencing / genotyping allows us to obtain genomic positions of interest (step E2) Pi, i=1, ..., N.

[0033] Genotyping can target positions of interest or not and can be generated by multiple procedures (microarrays, sequencing, or other). Thus, the process described here can be used both with results from custom-generated microarrays and with whole-genome sequencing of an individual (only positions of interest will be retained). The number of positions used depends on the desired level of uniqueness and security, according to the formula presented above. In other words, steps E1 and E2 can be implemented simultaneously.

[0034] The total number of positions studied can typically be 100.

[0035] The genomic positions of interest are not arbitrary but are such that, considering M subjects (the subject for whom the code is generated may or may not belong to these M subjects), these positions exhibit a binary polymorphism with an allelic frequency of 29% ±7% in the population. Furthermore, these positions respect Hardy-Weinberg equilibrium and are not located on a sex chromosome or on mtDNA.

[0036] More specifically, the ideal allele frequency of the polymorphism is 29%.

[0037] The polymorphism considered on the M subjects may, in the simplest way, concern only a single nucleotide (SNP in English for “Single Nucleotide Polymorphism " . Alternatively, the polymorphism considered on the M subjects may concern two nucleotides but it may also be a nucleotide insertion or deletion (INDEL).

[0038] Of course, the simplest polymorphism is that taken on a single nucleotide.

[0039] The polymorphism is binary because the differences considered are only between two alleles that differ by one position. We therefore consider one allele with a '1' state and another with a '0' state. This convention simplifies the subsequent steps of the process.

[0040] Preferably, but not exclusively, the positions studied are not located on a coding part (gene) of the genome.

[0041] We will return to these sequences later.

[0042] The resulting polymorphisms are then combined with each other, two by two, using logic functions to obtain a binary code cb (step E3).

[0043] In the case introduced, of a binary polymorphism, the combination consists of comparing the positions in the following way: The positions obtained are Pi, i=1 to N; we assign logical states '1' or '0' as follows: Pi='1' if at least one allele 1 is present in the two variations of SNPi, otherwise Pi='0'. We combine the Pis two by two to obtain the binary code cb.

[0044] Each element of the binary code corresponds to a combination of two sequences.

[0045] The combination is implemented by means of a logical function.

[0046] Examples of logical functions include: Exclusive OR (XOR), OR, AND, NOR, NAND...

[0047] Of course, the logical function can be a more or less complex combination of these elementary logical functions.

[0048] Alternatively and more generally, the combination can obey any type of function in order to have a maximum number of possible combinations.

[0049] Regardless of the chosen combinatorial logic, it is important to have combinations of positions whose genotypes can be considered independent, meaning they will not be in linkage disequilibrium. To avoid this possibility, it is necessary to choose positions that are physically distant from each other, ideally on different chromosomes or more than 100 centimorgans apart if they are located on the same chromosome. (Knowing that a distance of 50 centimorgans represents a 50% probability of recombination between two positions during a generation).

[0050] Once this binary code is obtained, it can be encrypted (step E4), but this is not mandatory. Encrypting the binary code protects it.

[0051] Additionally, the encrypted or unencrypted binary code is converted into a hexadecimal code (step E51) or a QR code (step E52). Indeed, a hexadecimal code (that is, a sequence of approximately twenty hexadecimal characters that can be directly translated from binary using a lookup table) is easier to store in memory, for example, and to read. Similarly, a graphical representation of this code, such as a barcode or QR code, can be generated to allow for automated optical character recognition.

[0052] As indicated, the positions of interest in the genome are those which, in a population of M subjects, exhibit a polymorphism with an allelic frequency of 29% ±7%.

[0053] In the case of humans, since subjects come from numerous countries across all continents, a position will only be of interest if the allele frequency is homogeneous and ranges from 29% ±7% across all populations. A polymorphism that is absent in one population or 100% in another would be excluded. Similarly, any positions associated with an individual's ethnic or geographic origin are excluded.

[0054] Positions are considered of interest if their frequencies conform to the predictions of Hardy-Weimberg models (this is the case for the vast majority of polymorphisms). According to this model, the frequency mentioned corresponds to positions where the polymorphism is present in 50% of subjects.

[0055] Specifically, consider a polymorphic DNA locus X with an allele frequency of 29% that has two alleles: 1 and 0. Thus, in a population, individuals can be homozygous (11 or 00) or heterozygous (10 and 01) for this locus. We can classify individuals into two states, A or B: State A represents being homozygous for the major allele (11) State B represents being homozygous for the minor allele (00) or being heterozygous (10 and 01)

[0056] We define as "common" those polymorphisms for which the 2 states (A and B) are equiprobable. That is to say, an individual has the same probability of being A or B (i.e., 50% each).

[0057] There figure 3This figure illustrates the relationships between allele frequencies, heterozygosity rates, and the percentage of individuals carrying the minor allele. Several pieces of information about the sequences are presented in this figure (obtained according to the Hardy-Weimberg principle): the first line indicates the allele frequency in the population of M subjects, the second line indicates the percentage of heterozygosity, and the third line indicates the percentage of individuals carrying the minor allele. It can be seen that for positions with an allele frequency of 29% ±7%, between 44% and 58% of individuals carry the allele in question (approximately one in two), such that there is almost an equal probability that two individuals will carry this sequence. Thus, given the amount of data and the fact that the codes are obtained using multiple sequences, the uniqueness of the code for a subject is guaranteed.

[0058] In addition to these frequency characteristics, the positions must meet further criteria: as mentioned previously, the positions must not be located on the sex chromosomes or the mitochondrial chromosome. Furthermore, preference will be given to positions that are not located on coding regions of the genome and that are not associated with physical or behavioral characteristics, nor with a predisposition to certain diseases. The combination of these positions is remarkable in that it allows for the identification of subjects without providing any information about them.

[0059] The criteria can be summarized as follows.

[0060] Criterion 1: These polymorphisms have a worldwide frequency of homozygotes carrying the minor allele of 50% (±10%), which is equivalent to an allelic frequency of 29% (±7%).

[0061] Criterion 2: For an individual to have an identical probability of being A or B, the frequency of the polymorphism must not vary greatly across human populations; therefore, not only must the global frequency of the minor allele of the polymorphism be 29% (±7%), but this frequency must not vary by more than 10% between two populations.

[0062] Criterion 3: The characteristics of the individual himself (sex or other physical characteristics, etc.) cannot be linked to his probability of being A or B. Thus, common polymorphisms located only on autosomal chromosomes (and not on sex chromosomes) must not be linked to known phenotypes or pathologies.

[0063] As an example, below is a list of SNPs on chromosome 14 that meet these characteristics: snp chromosome position rs111063713 14 104698456 rs2416015 14 47511528 rs4991272 14 59973009 rs3985117 14 47511530 rs7154083 14 83441172 rs1686571 14 20279151 rs57101715 14 90785895 rs55795050 14 90782024 rs8023212 14 90777846 rs11845387 14 90785495 rs574386930 14 96967163 rs2792111 14 20418489 rs148942138 14 79600280 rs3742666 14 90767860 rs118058626 14 39256730 rs551716374 14 44995118 rs4988990 14 101296722 rs2635566 14 20418538 rs67963498 14 41329594 rs4902256 14 64406065

Claims

1. A process for generating a unique identifier (I) of a subject from a genotyped DNA sample of said subject, the process comprising the steps of: - obtaining (E2) a number N ≥ 2 of genomic positions of interest, said genomic positions obtained being such that, in a population of M subjects, these genomic positions have a binary polymorphism having an allelic frequency of 29% ±7% for the minority allele; - combining (E3) pairwise the genomic positions obtained by means of logic functions so as to obtain a binary code bc.

2. The process as claimed in claim 1, wherein the allelic frequency is 29%.

3. The process as claimed in one of the preceding claims, wherein the polymorphism is a single-nucleotide polymorphism (SNP).

4. The process as claimed in one of the preceding claims, wherein the positions combined pairwise are not linked and are preferably at least 100 centimorgan apart or on different chromosomes.

5. The process as claimed in one of the preceding claims, wherein polymorphism is an insertion or deletion of at least two nucleotides.

6. The process as claimed in one of the preceding claims, wherein the combination consists of comparing genomic positions of interest as follows: - the positions obtained are Pi, i = 1 to N; - logic states '1' or '0' are assigned as follows: Pi = '1' if on both variations of the SNPi at least one allele 1 is present, otherwise Pi = '0'; - logical pairwise combination of Pi to obtain the binary code bc.

7. The process as claimed in one of the preceding claims, wherein the positions obtained are non-coding for the subject and at least do not include information on the sex of said subject.

8. The process as claimed in one of the preceding claims, comprising a step (E4) of encrypting the binary code obtained, the encrypted code also being binary.

9. The process as claimed in one of the preceding claims, comprising a step of converting (E51, E52) the binary code obtained into a hexadecimal code or QR code.

10. A system for generating a unique identifier (I) of a subject from a genotyped DNA sample of said subject, comprising a processor (10) configured to implement a process as claimed in one of the preceding claims.