In meiosis I, the gametocyte splits from a single cell (XXYY) -> 2 cells (XX + YY). In meiosis II these two cells split again (-> X + X, Y + Y). Hence in order for a father to pass on both an X and a Y chromosome to his son (eg in Klinefelter syndrome, w/ XXY chromosome), a spermatid must contain both an X and a Y chromosome, which means that there was an error in meisosi I. The stage at which meiosis I occurs is the primary spermatocyte.
submitted by โmerpaperple(44)
In meiosis I, the gametocyte splits from a single cell (XXYY) -> 2 cells (XX + YY). In meiosis II these two cells split again (-> X + X, Y + Y). Hence in order for a father to pass on both an X and a Y chromosome to his son (eg in Klinefelter syndrome, w/ XXY chromosome), a spermatid must contain both an X and a Y chromosome, which means that there was an error in meisosi I. The stage at which meiosis I occurs is the primary spermatocyte.