DNA testing during pregnancy paternity test

Pregnancy DNA testing uses modern medical methods to identify parent-child relationships. Pregnancy DNA is tested through a kind of free DNA of the fetus in the mother's body. Information about the fetus can be obtained from peripheral blood drawn from the mother. DNA testing can effectively detect whether the fetus has a parent-child relationship with the father, etc. The method of paternity testing is also very simple.

How to do DNA paternity test during pregnancy?

"DNA prenatal paternity testing", also known as embryonic paternity testing or fetal paternity testing, refers to the use of genetic technology to identify the biological father of the fetus. When the biological father of the fetus is unknown, "DNA prenatal paternity testing" can extract the free DNA of the fetus in the mother's body from the 'maternal peripheral blood', identify and detect the fetus's DNA (deoxyribonucleic acid) and compare it with the DNA of the suspected father to confirm the parent-child relationship.

The procedures for DNA prenatal paternity testing are not complicated. The general procedure is appointment - sampling - testing - report feedback. Generally, pregnant women can have blood samples drawn when they are more than 7 weeks pregnant.

Sampling method

Maternal peripheral blood

The blood sampling method is to draw 10ml of blood from the pregnant woman's arm vein, usually after 7 weeks of pregnancy.

DNA Prenatal Paternity Test - Probability Comparison

The principle of DNA prenatal paternity testing (maternal peripheral blood) is to compare the Y chromosome. The accuracy rate of denying parent-child relationship is nearly 100%, and the accuracy rate of denying parent-child relationship is 99.99%.

Probability comparison

Common blood type test: Use the corresponding blood type to detect parent-child relationship with an accuracy rate of 80%. DNA Prenatal Paternity Test - How it Works

Identification principle

The theoretical basis for determining biological relationship is Mendel's law of segregation. According to this rule, when gamete cells are formed, paired alleles separate from each other and enter their respective gamete cells. When sperm and egg cells are fertilized to form offspring, the child's two genomes come from one from the mother and one from the father; therefore, the same pair of alleles comes from one from the mother and one from the father. If the identification results conform to this rule, biological relationship is not ruled out; if not, biological relationship is ruled out (except for mutation cases). In most cases, the relationship between mother and child is known, and the requirement is to identify whether the hypothetical father and child are biologically related. At this time, by comparing the genotypes of the mother and the child, we can first determine the genes in the child that may come from the father (biological genes, OG).

Identification steps

Step 2: PCR amplification

The Chinese name of PCR is polymerase chain reaction. Simply put, the PCR amplification step is to replicate the required fragments in large quantities on the PCR instrument through enzymatic reaction, and amplify them to a level that can be seen through certain special instruments.

Step 3: Post-PCR reaction

This step is mainly the preparation stage for the ABI sequencer test. The double-stranded DNA is opened and some internal standards for detection are added, which are mainly used to mark the length of the detected fragment.

Step 4: Capillary sequencer detection

Since DNA is charged, through capillary electrophoresis, the electrophoresis speeds of DNA fragments of different lengths are different. Under the same voltage and the same electrophoresis time, the migration distances are different. These different distances can be distinguished by measuring the internal standards added in the early stage, and can also be displayed on the computer through certain software, which is convenient for detection personnel to process and analyze data.

Step 5: Analyze data and produce a report

The testers mainly analyze, summarize and calculate the results, and then issue identification conclusions and reports.