41 results about "Forensic dna" patented technology

The present invention provides methods and primer pairs for rapid, high-resolution forensic analysis of DNA and STR-typing by using amplification and mass spectrometry, determining the molecular masses and calculating base compositions of amplification products and comparing the molecular masses with the molecular masses of theoretical amplicons indexed in a database.

A novel suspension hybridization assay was used to determine nucleic acid copy number by flow cytometry. The assay was validated with low copy (lc) products ranging in length from 100 to 2304 bp conjugated to spectrally-distinct polystyrene microspheres. In the example provided herein, these conjugated microspheres were used as multiplex hybridization probes to detect homologous sequences in genomic DNA extracted from cytogenetic cell pellets and labeled with biotin-dUTP. Hybridization was detected with phycoerythrin-labeled streptavidin and analyzed by flow cytometry. Copy number differences were distinguishable by comparing the mean fluorescence intensities of test probes with a diploid reference probe in genomic DNA of patient samples and abnormal cell lines. The assay is capable of distinguishing a single allele and three alleles at a test locus from a biallelic reference sequence, regardless of chromosomal context. The assay is an improvement on previous methods which require prior amplification of locus-specific target DNA because, lc probes provide adequate specificity and sensitivity for accurate copy number determination of homologous targets. Because of its high sensitivity and accuracy, the assay is useful for determination of nucleic acid copy number for a variety of applications, including determination of genomic copy number in humans, animal models of disease and in solution, measurement of transcript levels, forensic DNA analysis, and quality control analysis in agriculture.

The invention provides a multiplex amplification kit containing 33 loca of a human genome. The multiplex amplification kit contains 18 A-STR loca which are recommended by a DNA database of the Ministry of Public Security to be used and also contains 14 Y-STR loca which are low in mutation rate and high in polymorphism and the Amelogenin locus, simultaneous amplification and detection on the 33 loca through a single tube is achieved, and synchronous amplification and detection on autosomes and Y chromosomes are achieved in a single experiment. The kit can directly amplify blood stains and saliva stains which take filter paper and an FTA filter as carriers without needing the template extraction and purification process and also can be suitable for DNA samples extracted through different extraction methods. The kit can be used for rapid investigation of a case, can improve the detection efficiency and increase the case investigation speed and especially has the significant effect on male sample trace detection in a raping case and father-child paternity test detection. The kit is wide in application range, good in compatibility and completely compatible with an existing legal medical expert DNA detection system.

The invention discloses a method and kit for extracting sperm cell DNA from a sexual assault case check sample by differential splitting decomposition. The kit comprises a box body, a DNA extraction bin and a DNA amplification bin are arranged in the box body, and a sexual assault check sample splitting decomposition tube for extracting target DNA, a first storage tube for storing a mild splittingdecomposition solution and a second storage tube for storing protease K, a third storage tube used for a sperm cell splitting decomposition and a fourth storage tube for storing reducing agent are placed in the DNA extraction bin. According to the method and kit for extracting sperm cell DNA from the sexual assault case check sample by differential splitting decomposition, the reagents needed forDNA splitting decomposition extraction and amplification are packed in the kit, the DNA extraction and amplification is convenient, a legal medical expert can conveniently indentify the DNA, and theidentification efficiency is improved; and a mild splitting decomposition environment is provided for the extraction of sperm cell DNA, the residual epithelial cell DNA in the sperm cell precipitationsolution is effectively removed, the pure sperm cell DNA is obtained, and the identification accuracy is improved.

A total forensic DNA casework management system and method for the deconvolution of mixed DNA samples using a novel, 3-rule algorithm to determine the proportional allele sharing of the sample's contributors. The process is fully document, can assess and process DNA anomalies and artifacts, and transforms raw STR data to produce final DNA profile types, peak height ratios, proportions, fitting criteria and associated graphs.

The invention discloses a Y chromosome parting kit and its preparation method and application. The present invention designs three pairs of public primer pairs, optimizedly select 12 X chromosome STR loci suitable for the genetic distribution of Chinese population and designs MiniSTR primers fro part of loci, and respectively adds the three pairs of public primers to the 5' end of the MiniSTR primers to obtain 24 additional primers; the use of the inventive kit can simultaneously amplify 12 X chromosome STR loci at a single-tube, avoids the competition between these primers and the formation of heterozygosity dimers, increases the amplification efficiency of each locus, wherein, the length of amplification products can be less than the 280bp, and has a high sensitivity (as low as 30pg), a higher STR parting success rate can be obtained and the amplification efficiency of medical examiner DNA degradation samples can be improved. The inventive kit has advantages of high sensitivity, high specificity, high detection efficiency, low preparation cost and the like.

The invention belongs to the technical field of forensic medicine, and particularly relates to a method for designing primers for compositely detecting multiple microRNAs (Micro Ribonucleic Acids), aiming at the technical problem of determining the tissue source of a body fluid blackspot by detecting microRNAs. According to the technical scheme, the primers for detecting the microRNAs include a specific reverse transcription primer REP, a forward primer PF and a reverse primer PR, wherein the specific reverse transcription primer REP sequentially comprises joint sequences ADP and P1 from a 5' terminal to a 3' terminal; the ADP sequentially includes a special sequence NHS and a TTTTC sequence of a nonhuman genome from the 5' end to the 3' end; the P1 refers to 6-8 basic groups which are complementary with the 3' terminal of an miRNA marker to be detected. The primers disclosed by the invention can be used for establishing the co-platform detection of miRNA and forensic medicine DNA genetic markers, can be used for compositely amplifying a plurality of miRNAs, can obtain more tissue source information from common forensic medicine trace detection material and has outstanding application value in the field of forensic genetics.

The invention provides hot-start Taq DNA (deoxyribonucleic acid) polymerase and a preparation method thereof. The hot-start Taq DNA polymerase is obtained by combining Taq DNA polymerase with aldehyde polysaccharide, the combination is achieved by reaction of an amino group of the Taq DNA polymerase with an aldehyde group of the aldehyde polysaccharide, and an amide bond can keep unbroken for more than five minutes at the temperature of 95 DEG C, so that polymerization activity of the Taq DNA polymerase is released; meanwhile, the polysaccharide capable of protecting the Taq DNA polymerase inhibits 3'-5' polymerization activity of the Taq DNA polymerase at the low temperature and is beneficial to improvement in PCR (polymerase chain reaction) efficiency as a protective agent of the Taq DNA polymerase. The hot-start Taq DNA polymerase prepared by the method can be widely applied to the fields of molecular biology, legal medical expert DNA detection and the like.

The invention discloses a short tandem repeat (STR) parting standard substance, which is a deoxyribonucleic acid (DNA) mixture and comprises 31 DNA segments with the nucleotide sequences as 1) to 31). In the invention, all allelic genes in the bits of Chinese people groups are researched and studied through focusing on the discovered STR gene bits in the existing forensic molecular genetics, and in addition, the biostatistics technology is used for studying the gene frequency distribution of each allelic gene. On the basis, the experiments techniques such as molecular genetics, molecule biology, cell biology, genetic engineering and the like are integrally utilized, the allelic gene DNA information base is developed and built for the first time, all of the allelic gene DNA segments such as STR bits are included, further, the forensic DNA standard reference system independently developed by China is further built, and the special artificially synthesized STR standard substance is formed.

The invention discloses a DNA examination reagent for sample examination, and a special primer thereof. A DNA examination primer group provided by the invention is composed of a primer pair group used for amplifying 21 Y-STR sites, a primer pair for amplifying a sex site Amelogenin, and a primer pair for amplifying an autosome SRT site. Experiments prove that the DNA examination reagent can simultaneously examine the 21 Y-STR sites and the autosome SRT site, and the primer specificity is high, so complete SRT typing can be obtained, peak patterns are sharp and intelligible, the balance is good, no Pull-up peaks or stutter bands appear, no non-specific artificial products appear, and legal medical experts' DNA large scale sample examination requirements are completely met.

The invention discloses a method for performing STR typing on a forensic mixed DNA sample. The invention provides a method for performing STR typing on a biological sample; and the method comprises the following steps of: extracting genome DNA of the biological sample, performing droplet type digital PCR amplification by taking the genome DNA as a template, sequencing an amplification product, andperforming STR typing according to a sequencing result, wherein the biological sample is a mixed biological sample. The invention also protects a method for performing STR typing on a DNA sample; andthe method comprises the following steps of: performing droplet type digital PCR amplification by taking the DNA sample as a template, sequencing an amplification product, and performing STR typing according to a sequencing result, wherein the DNA sample is a mixed DNA sample. The method provided by the invention has a huge application prospect in forensic DNA inspection.

The invention belongs to the technical field of bioinstrumentation and relates to a fluorescence composite amplification system of 30 Y-chromosome STR (Short Tandem Repeat) loca and a kit and application. The following 29 STR loca on Y-chromosomes can be simultaneously amplified: DYS393, DYS570, DYS19, DYS392, DYS549, Y-GATA-H4, DYS391, DYS439, DYS481, DYS635, DYS448, DYS533, DYS456, DYS389I/II, DYS390, DYS438, DYS576, DYS460, DYS458, DYS437, DYS385a/b, DYS643, DYS587, DYS645, DYS531, DYS596, DYS593 and DYS443. In conclusion, the system has the advantages that firstly, the system comprises 30Y-chromosome STR loca of human females, including common sites and low-mutation sites, is unique and novel, large in formation quantity and good in compatibility; secondly, the system is wide in application range, good in directivity, high in precision and applicable to legal medical expert DNA (Deoxyribonucleic Acid) analysis for all material evidence cases with cells of males. By adopting the system, all bioinstrumentation materials with male cells, such as bloodstains, seminal stains, saliva, hair, nails, cartilages and other human body tissues, can be identified, and FTA cards, whole blood, hair with hair follicles, oral cavity swabs and the like can be directly amplified.

The invention provides a primer group and a kit for simultaneously amplifying 37 Y-STR gene loci of human and application thereof, and belongs to the technical field of molecular genetics. In the invention, the 37 Y-STR gene loci comprise 36 Y chromosome STR gene loci and 1 Y-indel gene locus; 37 gene loci can be amplified in one reaction at the same time, the compatibility of current public security DNA database comparison is fully met, the amplification time is shortened, the identification efficiency and the detection material adaptability of the kit are improved, and the multifunctional STR identity identification requirements of current forensic identity identification, forensic DNA database construction and judicial genetic relationship identification can be met.

The invention aims at solving the technical problem in the prior art that analysis data of the amplified chromosome locus cannot enter the China DNA database, provides a DNA detection kit for auxiliary gender identification for a legal medical expert, or a method for adding auxiliary gender identification to a conventional kit. The key point is that Y special-shaped amplification primer of a fluorescent mark identical to the mark internal standard SIZ mark primer is added on the conventional kit, so as to amplify a segment in SRY zone of the Y chromosome, such as chromosome locus M175 and SRY. Meanwhile, the invention further discloses an SIZ mark primer sequence used for amplifying chromosome locus SRY and M175. Through the improvement, the purpose of auxiliary gender identification can be achieved without adding other components to the kit, or influencing the types of the kit; meanwhile, the amplification segment of Y specificity has the peak at the same fluorescent of the internal standard, peaks of fluorescent marks of other colors are not influenced, the introduction of the data into the public security ministry DNA database is not influenced, thereby conforming to the actual situation of recording for the China public security ministry.

The invention provides a method for realizing sperm cell separation of a mixed spot sample based on a polypeptide modified membrane. The method comprises the following steps: modifying a membrane by adopting polypeptide to obtain a polypeptide modified membrane; mixing and adsorbing a dispersion liquid of a mixed spot sample to be separated or a digestion product digested by an epithelial cell digestion liquid and the polypeptide modified membrane; discarding the residual solution, and washing the polypeptide modified membrane to obtain the polypeptide modified membrane with the surface enriched with male sperm cells. Preferably, the modification is physical modification or covalent modification. The membrane is loaded on the consumable or the membrane is part of the consumable. The methodfor realizing sperm cell separation of the mixed spot sample based on the polypeptide modified membrane can effectively separate male sperm cells and female epithelial cells in mixed spots to obtainmale sperm cells required by forensic DNA detection, and is ingenious in design, simple and convenient to operate, rapid in separation and suitable for large-scale popularization and application.