- 莫愁Lv 61 十年前最愛解答
Just I think.
It doesn't contain a DNA. Since according to the principle of amniocentesis, DNA will only be found if amnotic fluid is passing through the foetus' gastrointestinal system. Since during this process, some cells will be detached from foetus' intestinal wall so that the amniotic fluid withdrawn by needle from the amniotic sac will contain those cells. These cells are obtained by centrifuge. This explains not only why it can be used as prenatal test but also why water vapour doesn't contain DNA when it is expired from our lungs.
Due to no cells detached from our lungs or the air sac, the expired vapour will not contain our cells. As a result no DNA will be found in water vapour we expired.
I hope I am right.
- 1 十年前