The analysis of take off the oxygen pit sugar nucleic acid(deoxyribonucleic acid, DNA)’s applying to authenticate at the forensic medicine is about ten several businesses of in the last yearses, apply a molecular biology method at the forensic medicine realm, carry on the type in cent to the DNA of the living creature check that the case involve material and attain personal identify or the parents and children authenticate of purpose.There are more than 120 nations and region in the world having already applied a DNA analysis’ technique to handle a case, work°out a criminal case, civil case dispute problem, and investigate a corpse body source, include the victim in war and large disaster of personal identify etc., personal same affirm to near 100%.
One legal medical expert DNA analysis technical theories foundation
The DNA mainly constitutes to°from four kinds of alkali Ji adenine As, thymus gland Mi Ding T, guanin G and the afterbirth Mi Ding C, is the heredity material which exists in cell.Inherit the material-DNA included any machine body growth and function all essential informations.Mankind DNA imply 3.2 × 109 alkali Jis to, among them, about 99.9% DNA sequences be same and another 0.1% has difference between the individual.(in addition to livinging with egg double)The DNA difference of of individual have of the performance comes out in personal characteristic such as eyes, hair color and the skin color, more is to don’t express on personal physiology external appearance characteristic, having to use the special technique of laboratory then can be measurese.Used for the DNA technique of legal medical expert examination at the earliest stage-restriction part length many Tai examination(RFLP) drive people the popular image ground was called a DNA fingerprint a technique.DNA fingerprint technique after leading to go into a legal medical expert thing a certificate to authenticate, because of the high individual particularity of DNA fingerprint, consistency and heredity stability of of different organization of same individual, make individual same to affirm to become reality.After, establishment of the STR PCR technique, line grain body DNA analysis etc. technique, can raise individual to identify further all rate, and economize check hour, economical living creature check material.The DNAs of everybody’s cell nucleus come from parents both parties respectively, so can carry on a parents and children to authenticate through three allied body DNA examinations of the father female son.Cell centerline grain the body DNA is a matriarchal society heredity because of existing in cell quality, past can make use of line grain’s body DNA’s analysis to do a matriarchal society a single parents and children to authenticate, the house fasten analysis etc..
2 legal medical expert DNA analytical main methods
The 2.1 DNA fingerprint technique is from the mankind the DNA library in 1980 detection of a kind of variable establish a repeated sequence(the oftandem repeat of the variable number, VNTR), again moonlet DNA.After, people discovered one after another some is similar to with it of variable area.Exist many VNTRs that order on the gene set.The VNTR is mainly distribute in not code of the gene set area and carries a grain of part by chromosome mostly.”Core sequence”(repeated unit) in the VNTR grows 10 s 70 bps.Different individual gene set the core sequence for order of up same VNTR homology, but the repeated number of times discrepancy hang extremely.Past different individual the DNA fragment length of a little bit the same of VNTR area changes more and greatly, present many Tais in the community, namely VNTR length the fragment be many Tais.Therefore, these many VNTR length for order fragment many Tais identified to provide a beneficial proof for the individual in the forensic medicine.In 1985, British scientist’s Jeffreys etc. makes use of mankind DNA whom the VNTR”core sequence” probe DNA and restriction Mao Mao of making slice to carry on Southern to print a vestige miscellaneous hand over, acquire individual a different DNA fingerprint a diagram(DNA fingerprint) especially, call a DNA fingerprint a technique again.Jeffreys etc. uses that technique for the very first time with together immigrate of the infringement authenticate a case, affirmed blood relationship a relation and brought forensic medicine a technique revolution.The DNA fingerprint technical basic principle is:Make use of to have no restriction of slice the point in the VNTR sequence inside slice Mao like Hinf I, the Mao after slicing a gene set the DNA becomes many DNA parts that the length doesn’t wait.Giving or get an electric shock the DNA part that the Yong separates different size, using VNTR core a sequence is a marking probe to carry on Southern to print a vestige miscellaneous hand over, the different individual appears a series different miscellaneous hand over to take a type, do an individual to identify or correct confirmation criminal thus.Jeffreys etc. studied 20 DNA concerning white man a fingerprint, if used a kind of core sequence as the marking probe carries on Southern to print a vestige miscellaneous hand over, two personal possibility that the emergence completely and same alike takes a types are completely and same alike3 ×s 10 s 11;If make a probe with two kinds of core sequences, two personal possibility that the emergence completely and same alike takes a types then are low 10 s are at 5 ×s 19.The world population is about 5 ×s currently 109, therefore, in addition to livinging with egg double, have no two people of miscellaneous hand over to take a type will be completely same, positive such as everybody’s fingerprint similar, come to a complete individual different level especially.
The examination STR of the 2.2 STR cent type is short establish a repeated sequence(short tandem repeat) of brief name, and then call tiny satellite DNA.The STR constitutes to°from 2 s 10 bps repeated unit of short establish a repeated sequence.The part grows a 100 bps~500 bps.The STR is extensively distribute in mankind a gene set.According to the estimate, mankind gene set the each 20 bps have the STR that a 3 bps or 4 bps establish a repeated sequence the point.The Edwards waits for someone a research detection and about 50% STR points have highly many Tais.These highly many Tai STRs identified to provide another beneficial proof for the legal medical expert individual.The STR useds for a forensic medicine examination and have a following advantage:Don’t need miscellaneous hand over, as long as design a STR two side DNAs to lead a thing to treat side sample DNA to carry on simple PCR, then take to affirm or expel criminal according to the electricity Yong table;Because the STR is extensively distribute in the whole gene set, can analyze the DNA that the part declines a solution;The STR sequence is shorter, everyone orders STR to expand a condition to differ not and greatly, can be to a few STR points carry on synchronously expanding, and namely the STR PCR compound expand a technique to save time, economize a check material and raise to identify all a rate.The STR PCR the compound expand of method, is order several STRs of lead a thing to join same reaction system, fix DNTP, Mg 2+ densities, the Heng settles the circulation temperature and circulation number of times and regulate each lead a thing density to carry on to synchronously expand.The STR PCR compound expanded a technical establishment to consumedly raise STR system of personal discriminate all a rate.The Lins AM etc. carries on compound to expand to 12 STR points in 1998, personal match all a rate(Pm)<3.3 ×s 10 s 12, exceeded the single of the Jeffreys report way a little bit several probes get of DNA fingerprint 3 ×s 10 s 11 of match all a rate.The compound which have already developped to have 13 STR a point currently expand.
2.3 body DNA analyze line grain the body DNA(mitochondrial DNA, mtDNA) is a true pit living creature the heredity material of the outside of the cell nucleus.With pit the DNA compare, the mtDNA main characteristics is to exist in cell quality, and its heredity method inherits for the matriarchal society;The gene arranges in the mtDNA close.All of person mtDNAs grow 16569 bpses, only a grows one 000 bps of don’t code a sequence;A cell generally implies several hundred line grain a body, but each line grain body then imply 2~10 mtDNAs copy.A cell can reach to more than thousand mtDNAs to copy.Therefore, the mtDNA analytical intelligent degree want to compare DNA Gao of many.The different individual mtDNA doesn’t code the area D wreath nearby sequence to exist obvious difference.Expand, measure a preface with the PCR, can carry on personal identify.And the mtDNA hasn’t high request to the sample quality, if changes the organization, hair, bone, blood spot of sex bad dead, even from the sample take by ancient damaged site all can, only need the quantity of pg level to the sample demand.Because the mtDNA presents matriarchal society heredity, brothers sister the mtDNA of be in proper order all same, past can used for doing a body source to authenticate with same affirm, particularly make use of mtDNA to do under the sistuation that the parents can’t provide a thing certificate personal identify very successfully.The mtDNA sequence not only exists individual difference, but also still discovers race difference, past can also used for the race source which authenticates individual a problem.In fine, because of line grain body matriarchal society heredity way and a series of and special biology characteristic, make it have certain value in the forensic medicine realm.
3 legal medical expert DNAs are analytical applied
Currently there are more than 120 nations and applied DNA technique in the region in whole world handle a case, there are millions DNA proofs being adopt by law court annually.The DNA technique has become to make a conflict with crime member to reach agreement definitely in person power to dispute count for much tool.The our country starts carry on the legal medical expert DNA analysis research from 1987, currently public security official department thing the certificate authenticate center, each city and parts of Xing section in the regions unit all successful usage DNA to analyze a technique etc. and obtained a very big result in physically handle a case.The legal medical expert DNA is especially analytical the STR PCR technique is more and more valued.
Blood stain, hair, nail, tooth, muscular tissue or organ, the cigarette butt etc. check materials that 3.1 murder case murders leave on the scene all can carry on a DNA technique to authenticate, the spot of murder case is complex, regardless the thing certificate be remain what carry a body(the knife have, clothes, paper, wood, mud, cement ground, rock, leaf etc.) up, as long as investigate on the scene the personnel cautiously and in earnest collects a sample integrity, can make use of a PCR method to carry on an examination and pass an examination calculation to appear a thing certificate in the race crowd of accidentally match all a rate, if attain can science good timekeeper is same to affirm now.Even is hybrid blood stain(or mixture Jing spot) also no longer is can’t exceed of obstacle.Case:8 female youths happenned to be kill in the stone view mountain area in Peking City on the dawn of May 3, 1999 of especially big homicide case.From withdraw more than 80 blood stains to victimize person blood sample with 8 on the scene, carry on an examination in the meantime.Examine through several STR points, the first:The spot blood stain and 8 examinations of the dead blood kinds carry on a ratio as a result to, make each time a blood spot all certain is stay by who, thus explicit case hair hour each time on victimizing the person’s activity circumstance, and draw to appear a blood stain to distribute diagram, for probe a personnel to carry on the spot the reconstruction provided science basis;The second:Withdraw on the scene two kinds of commit crime the suspect person leave of blood stain, 1 kind stays for wearing socks after dye the blood, another a pair of slippers which is the spot to discover stay;The legal medical expert judges 8 deads to be all stab by two kinds of single blade knifes to die in the meantime.This case has a few cases to make for is the key which probes a personnel to bust this case.To blood stain and leave behind on the scene of the slippers carry on an examination, discover the result dissimilarity of the cent type of blood stain that STR cent type result and Tang inside the slippers of the slippers outward appearance noodles blood stain dye, and Tang blood stain inside the shoe is 5 among those the hybrid sample of the dead blood stain.According to this result analytical, blood stain inside the shoe for same case after make wear a sock to commit murder again wear slippers become, make sure socks footprint and slippers footprint of the spot to make for same case stay;The third:All check in the spot 3 blood stains is different from 8 deads etc. gene.On these grounds judged a case to make to once get hurt to bleed while commit crime, and authenticate a genotype that case make, for end affirm that the criminal provided a dependable proof.This case confirms to indeed make for a case after bust for, and the spot of the ninth blood stain and case make of genotype homology.The DNA technique success carries on the spot reconstruction and affirms that the crime suspect person provided and cans act for for this case of science basis, in order to investigate a work to point out a correct direction, there is prominent function.
3.2 rape and rape homicide case is rape and rape homicide case to usually discover a following thing certificate on the scene:Remain in the clothes, bed sheet, toilet paper or the semen spot on other objects;Mix a hybrid spot of have the female vagina secretion;Hideout pubic hair or hair, blood scar…etc..The DNA analysis technique can separate twos according to the difference of the female vagina secretion and the male sperm structure and withdraws pure sperm DNA, but is free from the influence of vagina secretion.Will leave behind on the scene of hybrid spot sperm the DNA be analytical result and suspect person DNA examination analysis result comparison, even rape by turn a case, pass contrast, can also get correct conclusion.Case:Deng manpower Wang2 Mou3 of the three-wheeled cart will just come to City soon on October 21, 2004, the life ground be not familiar heavy celebrated the book miss small spring to rape.After rape, the three-wheeled cart man rent away again the small spring along with takes of a Di ratio especially card cellular phone but escape the spot.20 divas, the police finds out important and suspect object, 29-year-old river south person, Wang2 Mou3, , the detection victimizes a person the thing certificate of the small spring still on Wang2 Mou3’s body at the same time.But face a proof, but Wang2 Mou3 refuse not to hand over to need any case details.End, make use of a DNA analysis’ technique to authenticate the DNA cent type of Wang2 Mou3 Xie3’s kind with stay is victimize the Jing spot DNA cent type in the everyone body consistently, this rob the case of rape just successfully tells to break.
3.3 unknown corpses, ground corpse case are in bust the unknown corpse, ground corpse case, at the time of can’t make sure a corpse identity, the usage DNA technique can solve a corpse source to affirm a hard nut to crack, can also make sure whether different corpse piece comes from same corpse or not and ignore criminal an usage what means carry on a processing, for example cook, burn, the medicine soak etc., ifs it weren’t for fire to become ashes, can carry on an examination.Case:Discover the weave bag which has a corpse piece in the some city different bus, the tramcar top and beard together respectively on December 10-13, 1998.(DO not discover head and parts of internal organses, at that time make popular panic)For carrying on a string combine case, the examination personnel carried on DNA analysis to the above-mentioned most corpse piece, affirm discover in the different location of the corpse piece is in the Chinese crowd of accidentally match all a rate is 3.3 ×s 1012, is same individual.Report that so-and-so disappearance in the valley requests to carry on a ratio with above-mentioned corpse piece according to someone to, carry on DNA analysis for the blood which looks for a corpse source to withdraw so-and-so younger sister, madam in the valley and daughter.Through the STR examination and the mtDNA sequence analytical, the ground corpse is a valley so-and-so daughter biology father of all the rate is 99.995%;The line grain body DNA is a matriarchal society heredity, the sequence variation alkali Ji and position homology of ground corpse and so-and-so younger sister in the valley, confirm ground corpse corpse source really for disappear personnel’s valley so-and-so.Is exactly a corpse source to really certainly make the case appear a turning point, in order to probe to provide a direction, for end uncovered this case to lay foundation.Some unknown skeleton cases especially disappear to search after several years of skeleton, keep in the skeleton more complete, under time limit not more than 20 as circumstances, the same can carry on authenticate and make sure that the skeleton really slices an identity.
3.4 parents and childrens authenticate a case some civil case in courts which divorce case in, the both parties the party concerned causes to brings up power or bring up a fee because of whether kid is own to produce objection or not etc. the quarrel of problem, over a long period of time long-lost sons and daughters after grow up, or hospital occurrence the infant be wrong to embrace and immigrate affairs or household register to sell reason, overseas or HongKong-Macau the pedestal compatriot look for close etc. circumstance, need to confirm a relative relation, carry on DNA to authenticate is the most accurate way.Local just gradual combine together the DNA examination, database, Internet’s three techniques currently, build up a national database, can carry out a national scope intranet and search, can consumedly lift high-efficiency with save time.
The applied legal medical expert DNA of 3.5 other aspects analyzes a technique in addition to carrying on DNA analysis to the mankind, can also carry on a kind to belong to authenticate to the pet, domestic animal, wildlife…etc., the individual identify and close the power relation authenticate and used for the DNA technique that the animal authenticate a main wired grain preface analysis, PAPD analysis and STR etc. of the measure of body DNA analytical.Dog and cat are mankind living medium get in touch with the most animals.The dog may be the cause who takes the offensive a person but be subjected to an examination, on crime member’s body or product up discover the hair which has a dog, the conation passes an examination these hair of dogs to judge their relativities with the hair of suspicious dog.Case:A women are murder, discover a few hair of dogs by the side of the corpse.Led in a little while, and then discover a women being murder, several hair of dogs of the by the side of the corpse discover of the same.Commit crime way likeness, all on the spot leave appearance a top the hair of dog of the likeness, think this two cases as same people is.Line grain body analysis expresses the hair of dog sequence of two spots homology, all is a variation body 8, is a very seldom seen genotype, collect the hair of dog of 7 suspect families, carry on a line grain body DNA analysis, their types distinguish to 1, 3, 4, 5, 5, 5 and 5, enunciation the spot of hair of dog and their dissimilarities.More important BE, the spot discover of hair of dog genotype is in currently 3 dogs the kind detection, contracted to leave behind the dog scope of hair of dog on the scene.In addition, the crime member is in the process of commit crime in by all means will by accident make own body, clothes, shoes and socks, commit crime tool or pileup to take the object in the surroundings environment of have the crime the spot, like mud, plant of leaf’s slice, flower petal, seed, pollen and fruit or juice etc., perhaps the corpse body be stained with these materials.Carry on to these materials analysis, judge to commit crime whether suspect person has been to case the spot or not, perhaps make sure the first crime the spot of position, usually bust some cases to have an important function.In the actual case, plant or mud sample condition adhered to on body or corpse of the crime member badly, with lend a common classification to learn probably can’t confirm, classify them, therefore to examination and exploitation less of these plant and mud samples.Along with the technical development of the molecular biology, can apply a DNA technique to carry on analysis to these samples, examination, make sure the likeness of their categories and surroundings environments
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