When it comes to birth and genetics most of us believe every cell in our body contains a mixture of genes from both parents but genetic sequencing reveals that is not necessarily the case.
It used to be believed the placenta and womb were designed in such a way that nutrients could pass from one to the other without cells being able to pass, but it is now known that some complete cells from the mother are not only able to pass into the foetus, but also able to thrive and multiply.
What this means in practice is that as well as having your own cells, containing mixed DNA from both parents, many of us may also have complete cells which once belonged to our mother, and which contain our mother’s full DNA.
Taking that a stage further, your mother also has a chance of having some whole cells from her mother. This means there is also a slight chance you will not only have some complete cells from your mother, you may also have some complete cells that once belonged to your mother’s mother.
The reverse is also true. It is now also believed complete cells from their baby may pass through the placenta and remain in the mother’s body for a considerable time after she has given birth, possibly in some cases for the rest of her life.
Those cells may end up anywhere. For example, some brain cells and heart cells in a baby may contain the complete DNA of their mother, and some brain and heart cells in a mother may contain the complete DNA (part mother and part father DNA) of their baby.
To sum up birth and genetics, if you are a woman, your baby may literally be part of you, and you may literally be part of your baby. Fuller info in ‘A Brief History of Life‘.
