The first paragraph in the article sounded wrong. It says that "the brain of a woman is composed of two different types of cells. One type has an X chromosome inherited from her mother, and another type of cell has an X chromosome from her father", but I remembered that all cells in a woman have both X chromosomes.
It turns out the correct paragraph should say: "One type has an ACTIVE X chromosome inherited from her mother, and another type of cell has an ACTIVE X chromosome from her father".
Here the excerpt from the relevant linked article, which explains it better:
> A few weeks after conception, one of the two X chromosomes in each cell of a female's body is randomly deactivated. As each of these cells in the developing fetus multiplies, its descendant cells all have the same X chromosome activated. This leads to a patch of cells that all have the same active X chromosome (say, the X from the mother). A different fetal cell may have randomly deactivated the mother's X chromosome, and so all of its descendant cells each have the X chromosome from the father.
Thank you for posting that. I read this paragraph and the weak language instantly made me wonder this was doing on HN. I would not consider those two "types" of cells.
I don't understand how this passes for publishable material. I could have written better when I was 17, and I was a terrible writer back then!
It turns out the correct paragraph should say: "One type has an ACTIVE X chromosome inherited from her mother, and another type of cell has an ACTIVE X chromosome from her father".
Here the excerpt from the relevant linked article, which explains it better:
> A few weeks after conception, one of the two X chromosomes in each cell of a female's body is randomly deactivated. As each of these cells in the developing fetus multiplies, its descendant cells all have the same X chromosome activated. This leads to a patch of cells that all have the same active X chromosome (say, the X from the mother). A different fetal cell may have randomly deactivated the mother's X chromosome, and so all of its descendant cells each have the X chromosome from the father.