Chorionic villus paternity testing

In the early stages of pregnancy, the baby's condition can be determined based on the baby's fur. Some mothers become pregnant unexpectedly and hope to do a fur DNA test to determine whether the fetus is their biological parent. So, where can we do the DNA test for fur? And why can't collateral relatives marry for multiple generations? Let the editor lead everyone to understand these aspects.

Where to do plush DNA identification

It can be done in a reliable hospital outpatient clinic. The fetal hair assessment obtains the fetal hair sample. In the early stage of pregnancy, the sperm and egg combine to develop and form the gestational sac. A layer of trophoblast will appear on the surface of the gestational sac that touches the uterine wall, and many villous protrusions will appear on the surface of the trophoblast. This protrusion is the hair. The hair obtained is not the hair on the child's body, but the bumps on this layer of trophoblasts, which has no effect on the growth and development of the child. Generally, chorionic villus sampling can be performed at 11-15 weeks of pregnancy (the specific gestational age is calculated based on the expected date of delivery. If the menstruation is irregular, the gestational age can be determined by B-ultrasound) to obtain a small amount of villus tissue for DNA sampling testing. The entire line is obtained by the chief physician under the supervision of B-ultrasound. Since the mother's DNA information may be contaminated during the acquisition process, the mother's sample must be provided when doing the hair evaluation.

Step 1: DNA acquisition

The fetal hair assessment obtains the fetal hair sample. In the early stage of pregnancy, the sperm and egg combine to develop and form the gestational sac. A layer of trophoblast will appear on the surface of the gestational sac that touches the uterine wall, and many villous protrusions will appear on the surface of the trophoblast. This protrusion is the hair. The hair obtained is not the hair on the child's body, but the bumps on this layer of trophoblasts, which has no effect on the growth and development of the child. It is usually carried out after eight weeks of pregnancy, and all samples are obtained by the chief physician under B-ultrasound supervision. Because the mother's DNA information may be contaminated during the acquisition process, the mother's sample must be provided during the fur assessment. The DNA contained in the sample cytoplasm is then extracted, and then a certain amount of purification is carried out to remove the impurities in the sample.

Step 2: PCR amplification

The Chinese name of PCR is polymerase chain reaction. Simply put, the PCR amplification step of Huake Genetics is to make a large number of copies of the desired fragments through enzymatic reaction on the PCR instrument, and enlarge it to a level that can be seen by some special instruments.

Step 3: Post-PCR reaction

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

Step 5: Analyze data and present report

The main task is for the inspection staff to analyze, summarize and calculate the results obtained, and then issue an appraisal conclusion and report.

Collateral lineages cannot marry for multiple generations

my country's Marriage Law explicitly stipulates that one of the situations in which marriage is strictly prohibited is that marriage between direct blood relatives and collateral blood relatives within three generations is strictly prohibited. Direct blood relatives refer to the blood relatives who gave birth to you or the generations before and after you gave birth to you, that is, the blood relatives you are descended from or descended from you. Tracing back to parents, grandparents, great-grandparents, etc., down to children, grandchildren, great-grandchildren, etc., they are all direct blood relatives.

Collateral relatives refer to blood relatives who are difficult to relate to each other but are born from the same ancestor. For example, brothers and sisters from parents, uncles, aunts, nephews and nieces from grandparents, and cousins ​​are all collateral relatives. Those who are alive with the same father and mother are full blood relatives, and those who are alive with half father or half mother are half blood relatives.

The categories where consanguineous marriage is not allowed:

1. Marriage is naturally not allowed between parents and their children, between grandparents and their grandchildren, and between grandmothers and grandfathers and their grandchildren.

2. You cannot marry your uncle, uncle-in-law, aunt or uncle-in-law.

3. You cannot marry your brothers and sisters, cousins, or cousins.

4. Brothers and sisters who share the same father and mother (including half brothers and sisters). That is, children of the same parents cannot get married.

5. Uncles, aunts, uncles, aunts and nephews of different generations. That is, the eldest uncle cannot marry his brother's daughter.

6. An aunt cannot marry her brother’s child; an uncle cannot marry his sister’s daughter; a woman who is menstruating cannot marry her sister’s child.

As for the "relatives and friends" that ordinary people often refer to, there is usually no direct kinship relationship between them and they do not fall into the category of direct relatives whose marriage is strictly prohibited.