genotype of the placenta - (Dec/05/2005 )

Does anyone know if the genotype of the placenta is tha same as the fetus or the mother? Thank you very much!

I am pretty sure that the Placenta DNA is the DNA of the fetus

it's the foetus

hi
unique cell start dividing itself before arriving in uterus (at morula stage). Then implant into uterus and start developping embryo and the appendages that are needed. Hence, as placenta is derived from foetus cells, genotype is the same as fetal one.

Many thanks!

placenta is derived from the extraembryonic tissue of the embryo, it's the genotype of the child/fetus. CVS samples are taken from the chorion within the placenta to type the developing fetus.

Hi Haiyan

I actually joined this forum to help answer this question but never got round to it......better late than never I suppose

The placenta does not solely represent the fetal genotype as has been suggested. This organ actually consists of both fetal and maternal tissue. The umbilical cord and placental membranes are fetal in origin. The main part of the placenta, the bit that looks like a disc, consists of both fetal and maternal tissue. It is sometimes described as having a fetal surface (smooth in appearance - the side from which the umbilical cord projects) and a maternal surface (the other side - "meaty" and ragged in appearance - the side which is anchored into the uterine wall. See here for a brief overview.


The chorionic villi within this disc (small finger like projections) are fetal in origin but they are surrounded by maternal tissue called decidua. If this tissue is biopsied (from just underneath the smooth surface) then great care needs to be taken to separate the fetal component (villi) from the maternal component (decidua) - otherwise any testing of this extra-embryonic fetal tissue will be prone to contamination with maternal cells.