When they join together to form a zygote, they’ll combine to create the full 46 chromosomes (two sets of 23, one from each gamete) needed for a full human cell. What happens when zygotes don't ...

The zygote inherits two fully active X chromosomes and begins re-inactivation of the paternal X chromosome (XP) at the 4- to 8-cell stage. In the trophectoderm (extra-embryonic cells, shown in ...