How about the genetic paternity test in China?

Paternity identification is to use the theory and technology of medicine, biology and genetics to analyze the genetic characteristics and judge whether the relationship between parents and children is a biological relationship from the similarity of morphological structure or physiological function between offspring and parents.

Reasons for paternity test

The inducement of paternity test: With the development of science and technology and the change of traditional family concept, the level of modern biotechnology coincides with the demand. According to the different purposes of identification, paternity test can be divided into judicial identification and personal identification.

1. The personal paternity test itself is not public, so the client has the right not to provide any documents. Samples can be sampled by themselves and sent to professional appraisal institutions, and appraisal results are only provided to appraisal clients. The appraisal result can be used as the basis of appeal, but it cannot be used as evidence in court. It can only be used as a certificate of the expert's parental authority appraisal and can be used as one of the evidences, but the accuracy of the appraisal process and results is consistent with that of judicial appraisal.

2. The judicial paternity test is completely open. The father, mother and children of the parties must agree to face-to-face identification, and relevant valid documents, including ID cards and household registration books, should be brought together. The appraisal results can be used for judicial purposes (registration of household registration, immigration, litigation, etc.). ) can also be used as evidence in court.

1) Judicial expertise can only be applied to litigation activities, which is a scientific appraisal activity initiated by judges in the process of specific litigation and trial procedures. In other words, if you don't participate in litigation activities, that is, if you don't go to court, you don't need to do judicial paternity test; It is necessary to go to court. After the lawsuit reaches the court, the appraisal initiated by the court is called judicial appraisal.

2) Judicial authentication activities must be carried out in accordance with the procedural law and relevant judicial interpretations, and the conclusion that the procedure is illegal cannot be used as authentication materials. Judicial expertise should be legal in subject, materials, procedures, steps, methods and standards. Judicial expertise must be issued by relevant institutions (public security organs, people's procuratorates and people's courts), and it is called judicial expertise after a series of judicial notarization procedures, and it is only used as court evidence. The appraisal conclusion is valid only after cross-examination by the court.

3) At present, more than 80% of paternity tests have not yet started judicial identification, and they are all personal identification.

Personal identification is a biological identification of an individual's genetic genes by an identification agency. In the sampling process, there is no need for the public security inspection law to issue a power of attorney, and it is not entirely necessary for the applicant to provide ID cards and other documents and consent forms. It can be used as one of the evidences, but the accuracy of the appraisal process and results is consistent with that of judicial appraisal.

1) judicial paternity test

Inheritance disputes should be determined whether they are biological relations;

Identification of rapists;

Claiming abducted children;

Settle before marriage and settle after super-life;

The identity of the victims (air crash, tsunami, etc.). ) is not recognized;

Custody dispute.

2) Personal paternity test

Suspect that the child is not biological;

Suspect that the delivery room or nursery of the hospital has adjusted the wrong newborn;

Separated families recognize relatives. Paternity identification also includes: kinship identification (paternal or maternal), immigration identification, etc.

Paternity test of upper-class families

First, in the following cases, you need to do a paternity test before signing up:

1, no birth certificate. For various reasons, the child was not born in a hospital with obstetrics and gynecology qualifications, or was not born in a hospital, so there is no standardized birth certificate, and paternity test is needed when registering. Or there is a birth certificate, but the parents' names on the birth certificate are inconsistent with the names on the ID card and household registration book, and paternity test is needed.

2. Because the child was abducted and lost, it was later recovered through various channels. The household registration needs to be with the biological parents and needs a paternity test report to prove it.

3. Giving birth out of wedlock. The existing legal documents can't prove the child's biological parent relationship. Or a single-parent family, the child's household registration needs to be transferred from the father to the mother, or from the mother to the father, and paternity test is needed.

4. Abandoned children go home. If the child is adopted and needs to be adopted again, or because of evading family planning, it is necessary to transfer the child's household registration to the biological parents' name in the name of others, and paternity test is needed.

5. The adopted children go to their families. It is necessary to prove that the child is not related to the adoptive parents.

6, special provisions of the department. Because some departments are afraid that people from other industries will enter special industries when recruiting, they need parents and children in their own industries to prove paternity. For example, the recruitment of Zhengzhou railway system requires proof of paternity test.

Second, the procedures required for paternity testing:

Paternity identification belongs to the process of self-certification, so the identification certificate only needs to be provided by the appraiser:

1. Documents that can prove the identity of the appraiser: such as ID card, household registration book, military identity certificate, birth certificate, etc. Without the above proof, you need to go to the people's government at or above the township level, street offices and public security police stations to apply for identity certificates.

2. The appraiser must take blood from the judicial appraisal center to participate in the appraisal and complete the identity verification. Mainly to verify the identity certificate, leave fingerprints and take photos.

3. If it is not convenient for the appraiser to go to the judicial expertise center for sampling, he can contact the staff of the judicial expertise center for on-site sampling and identity verification.

Third, choose an appraisal institution.

At present, there are many institutions that do paternity testing, but paternity testing belongs to the category of judicial expertise. Therefore, the selection of authentication institutions must have a judicial authentication license, and the paternity test report must be effective and recognized by the public security and judicial departments all over the country. If necessary, an internationally recognized judicial authentication institution is needed for authentication (for example, children are trafficked abroad or Hong Kong and other regions).

Iv. Personnel involved in paternity test:

Only consider the needs of entering the household, which can be father-son (female) identification or mother-son (female) identification, and enter the household based on the identification conclusion. However, due to many factors such as gene mutation and paternity test, paternity test is best for parents, children and daughters.

Fifth, the appraiser has received blood transfusion from others within six months, or bone marrow transplantation within two years, so it is impossible to draw accurate conclusions. Please avoid the above time if you need identification.

Original paternity test method

Appearance contrast

Due to genetic reasons, father and son, mother and son, brothers and sisters have some similarities in appearance and skin color. It is probably the most primitive method to determine the parent-child relationship through the comparison of appearance and appearance, but this method is only a guess and judgment for reference.

Bone loss test relatives.

The method of bone drop test is to drop the blood of the living on the bones of the dead. If blood can penetrate into the bone, it is concluded that there is a blood source relationship between the living and the dead, otherwise there is no blood source. The Biography of the Sages in Huiji, written by Xie Cheng, a Wu native during the Three Kingdoms period, records the case of using the blood of the younger brother to hold the bone of the older brother. (The Biography of Nan Shi Wang Yuzhang also records the test of relatives with his son's blood dripping on his father's bones; Song Ci, a famous forensic scientist in the Song Dynasty, included the method of testing relatives by breaking bones in the Collection of Injustice. From a modern point of view, this method is not scientific, but it is the first to use blood type to identify the relationship between blood sources.

Drop blood to test relatives

Blood test, also known as blood test, is to put a child's blood and an adult's blood together. If they can blend together, they are the parents' own, otherwise they are not. This method of sample identification was recorded in China's forensic works in Song Dynasty. This method has no scientific basis. The blood of parent-child relationship may not be merged, and the blood of non-parent relationship may be merged.

Modern paternity testing method

1, blood group test

Blood type paternity test is to confirm the parent-child relationship through the comparison of blood types.

According to Mendel's genetic law confirmed at the end of 19, people realize that human blood types are passed on to the next generation according to genetic genes, so children born to parents of a certain blood type also have corresponding blood types, which lays the foundation for blood type identification of parent-child relationship.

The blood type system used for blood type detection to determine parent-child relationship mainly includes:

abo blood group system

MN blood group system

Blood group of rhesus monkey

Ss blood group system

Hp blood group system

The more blood group systems tested, the higher the accuracy. If the blood type test results show that there is no kinship, the conclusion of negative paternity can be made, but the result of kinship cannot be completely determined as paternity.

In 1970s, it was found that the antigens of white blood cells could be used for paternity testing, with an accuracy rate of 80%. Combined with blood type test, it can achieve high accuracy.

2. Identification of chromosome polymorphism

In the 1980s, medical scientists pioneered the technology of paternity testing by using chromosome polymorphism, also known as heteromorphism, which refers to the slight variation of various chromosome shapes common to normal people (such as satellite enlargement, duplication or deletion, variation of fluorescence intensity in chromosome regions, etc.). ), and this polymorphism is heritable. This technology uses its form to identify parent-child relationship, which depends on the subjective judgment of technicians, and its accuracy is not satisfactory.

3.DNA identification

At present, DNA typing is the most commonly used method to identify parent-child relationship. Human blood, hair, saliva and oral cells can all be used for paternity testing, which is very convenient.

A person has 23 pairs (46 chromosomes), and a pair of genes in the same position of the same pair of chromosomes are called alleles, usually one from the father and one from the mother. If the allele of a DNA locus is detected, one is the same as the mother and the other should be the same as the father, otherwise there is doubt.

Using DNA for paternity testing, as long as ten to dozens of DNA loci are detected, if they are all the same, the paternity can be determined; If more than three loci are different, the parent-child relationship can be ruled out; If one or two loci are different, we should consider the possibility of gene mutation and detect some loci to distinguish them. In DNA paternity, the accuracy of denying parent-child relationship is nearly 1 0,000%, and the accuracy of affirming parent-child relationship can reach 99.99%.

Frequently asked questions in DNA paternity.

1. What is DNA paternity?

DNA (deoxyribonucleic acid) is the atomic substance of cells in human body. Each atom has 46 chromosomes. In addition, male sperm cells and female eggs each have 23 chromosomes. When sperm and eggs combine, these 46 atomic chromosomes create life. So everyone inherits half of the molecular substances from his biological father, and the other half is obtained from his biological mother.

DNA paternity is very different from the traditional blood test. It can be tested on different samples, including blood, cheek cells, tissue cells and semen samples. Because blood types, such as type A, type B, type O or type RH, are common in people, it is not as effective as DNA paternity's. Everyone's DNA is unique except the real twins. Because it is so unique, it seems.

2.2 How accurate. DNA paternity?

DNA paternity is the most accurate paternity test at present. If the DNA patterns of the child and the tested man do not match on one or more DNA probes, then the tested man is excluded by 100%, that is, the possibility that he is the biological father is 0%. He can't be the biological father of the child.

If the DNA patterns of the mother, the child and the tested father are completely consistent, then the probability of more than 99.97% can be calculated, which proves that he is actually the child's biological father. Most American courts accept a 90% probability as proof of paternity.

3. Do children have to be a certain age to be DNA paternity?

There is no age limit in DNA paternity. Traditional blood type tests require children to be at least 6 months old. In addition, a large number of blood samples are needed, usually more than two teaspoons. This method is difficult to apply to children. On the contrary, DNA paternity only needs a few drops of blood (about 65,438+0/4 or 65,438+0/2 teaspoons) or cheek cells obtained by oral friction. This test with a small amount of blood or oral cavity makes it possible to test DNA even for newborn babies or children. Because DNA is formed in the binding stage, chorionic villus sampling /CVS or amniocentesis can be used even before the baby is born.

Paternity tests can be conducted on the samples collected by the funeral home staff of the deceased. When a person dies or disappears, his or her DNA tissue can be rearranged on his or her blood relatives.

4. Can paternity test be conducted without the mother's participation?

Yes DNA paternity is very effective, even when mother is away. Whether the mother is involved or not, if the DNA tissue arrangement of the child and the tested man does not match, then 1000% of the tested person will be excluded as the biological father. If the organization arrangement is consistent, then we can calculate the probability of biological father above 99.95%. If an individual carries a minor child for the test, he/she should carry his/her identity document and sign the relevant documents.

5. Is the oral (cheek) smear examination accurate?

Another way to test blood is a sample collection method called oral swab. Because DNA exists in every cell of the body, the accuracy of the test results obtained by the samples collected by smear method is the same as that of blood samples.

When collecting samples, gently swab the child's mouth to extract DNA from it. This procedure is not mandatory, painless and most suitable for children. Because this method can be used to extract DNA, more steps can be taken, such as taking blood from adults and taking samples from children with oral swabs. Adults can also choose to use oral swab testing.

6. Is it okay that the people being tested are distributed in different cities?

No problem at all.

7. Do you need a hospital certificate or a lawyer's letter to be a DNA paternity?

Not necessarily/possibly ..

8. Can a baby have a paternity test before birth?

Yes, with DNA identification, a child can have a paternity test before birth. The DNA test can be performed by CVB placental hormone, usually during pregnancy 10 to 13 weeks, or by extracting amniotic fluid during pregnancy 14 to 24 weeks. Any type of operation should be performed by obstetrician /GYN doctor.

9.9 principles and procedures. DNA paternity.

DNA is extracted from a few drops of blood, cheek cells or cultured tissue fibers. Cut the DNA sample into small pieces with structural domain elements and put them into gel. The small pieces of DNA are pushed to separate by electrophoresis tank-the thinnest is farthest and the largest is nearest. After that, the separated genes are placed on nylon membrane, and special DNA probes are used to find genes, and the same genes will be condensed into one. Then, in the X-ray environment, with special dyes, the black bar code condensed by DNA probes appears. This kind of bar code that children can see is very special-half matches the mother's and half matches the father's. This process is repeated several times. Each probe is used to find different parts of DNA and mapped into a unique barcode. Using several groups of different probes, the paternal probability or resolution can exceed 99.95%.

10. Can you explain the results of the paternity test?

The child will have the same stripe as the biological mother and another bar code as the biological father to confirm. 1 (AF 1), and this person is the biological father; The excluded man (AF2) does not have the same barcode as the child.

Confirmation of paternity: the probability of paternity is greater than 99.99% or greater (legally proved to be the biological father)

Negative paternal relationship: three or more gene loci do not conform to the genetic law (100% excluded as biological father)

Due to the large population base in China, it is generally recommended to compare more than 20 STR loci to reach a correct conclusion.

Common sense of paternity test

What is the difference between legal use appraisal and personal appraisal?

The method and accuracy of legal use appraisal and private appraisal are exactly the same. The only difference is that the identification of legal use requires the client to provide fingerprints, photos and identification, and the sample sampling process requires legal witnesses. Private identification does not need to provide photos or fingerprints, and the whole sampling process can be carried out by itself, which is completely confidential. Therefore, the DNA identification results of privately collected specimens have no legal effect.

Can paternity test be conducted without the participation of the biological mother?

The biological mother can choose not to participate in the appraisal. In paternity testing, the samples of the child and the presumed father are usually enough to know the result, and the mother can choose not to participate in the test. The birth mother has also been tested, and the conclusion is more accurate. Because a child's genes come from his mother and one from his father. If there is a biological mother as a reference (that is, parental identification), the gene of the biological father can be clearly deduced according to the genotype of the mother and the child, and then compared with the controversial father (that is, you). If there is no mother, the gene of the biological father is directly deduced from the gene of the child. There are many possible situations, and the numerical deviation obtained by statistics is relatively large.

In fact, we have simulated the detection results of the commonly used 15 STR locus by computer. With this detection system, two unrelated people, at least three of whom violated the genetic law, and 99.99% non-fathers can be excluded, but11000 may be misjudged. So the difference between us and other institutions is that we have added a kit and nine detection indicators, which are more accurate and avoid deviations as much as possible. This is also the reason why the single parent appraisal fee is higher than that of the biological mother.

Do I need to take part in the paternity test?

Paternity identification can be divided into two types, one of which needs judicial effect, such as litigation, immigration, household registration and so on. The other is just knowing the result, which does not involve judicial application. For the former, just provide the customer's identity information. Parents provide identity cards, and children can provide birth certificates or household registration books to prove their identity (proving that the parties concerned are the children's guardians). Those who have entered the judicial process or have hired a lawyer may entrust a judge or lawyer to make an appraisal. It can also be entrusted by both parties. For the second type, you don't need to provide any information, you can be anonymous, and you can bring your own samples. The two charging methods, appraisal methods and appraisal standards are exactly the same, only the procedural differences, that is, a legally effective judicial appraisal book, which requires us to review the identity cards of the parties and take photos.

Fetal paternity test

Fetal paternity test refers to the genetic paternity test of the fetus by using genetic technology. When the genetic father of the fetus is unknown, "prenatal paternity test" can extract cells from the amniotic fluid of pregnant women and confirm the paternity by identifying the DNA of the fetus. Paternity identification can be used to detect fetal DNA from fetal period through villus biopsy and amniotic fluid identification. Chorionic puncture can be performed after 10 weeks of pregnancy, and amniotic fluid test can be performed after 16 weeks of pregnancy. Zhao Fa's editor. Com introduces the method of fetal paternity test.

I. Chorionic biopsy

1. It is necessary for pregnant women to have a higher cleanliness of leucorrhea, 1 degree;

2. Pregnant women should not have inflammation such as cold, sore throat and fever.

3. Routine blood examination shows that the white blood cells are not high.

Two. Amniotic fluid identification

1. Pregnant women should not have inflammation such as cold, sore throat and fever.

2. Routine blood examination shows that the white blood cells are not high.

Tips for fetal identification of pregnant women;

1. Pregnant women should pay attention to rest before operation. If they have a cold, sore throat and fever, they shouldn't have an operation.

2. You can have breakfast on the day of hospital examination, and you don't need to draw blood on an empty stomach.

3. Before pregnant women with villus biopsy come, they need to have a B-ultrasound. Make sure you are pregnant, have a leucorrhea check, and you can operate if the cleanliness is normal.

4. Pregnant women can't take a bath on the day after operation and can't have sex for half a month.

Wear more clothes when you go out to avoid catching a cold.

It is understood that paternity testing is divided into single-parent testing and paternity testing, among which single-parent testing is the majority, that is, one spouse takes the child to the other party for identification, and all children lie about "physical examination". According to the person in charge of the judicial appraisal institute, about 70% of the paternity appraisers are men, and they all secretly bring their children to do the appraisal in order to understand. "The child doesn't look like me" and "The child was born at the wrong time" are all reasons why these men suspect that the child is not their own.

On the one hand, the rapid growth of paternity test shows that society is progressing and people are willing to solve problems through scientific means. On the other hand, it also shows that there is a growing lack of trust and understanding between husband and wife and lovers. Bian Xiao suggested that we should be cautious about paternity testing and have enough psychological endurance for the results so as not to cause harm to spouses and children.