Then there is Meiosis for our gametes, because they (gametes) are different.

然后是配子减数分裂，因（配子）是不同的。

The answer lies within the amazing process of meiosis.

答案就在惊人的减数分裂过程中。

The secondary oocyte stops in metaphase of meiosis 2, and waits for fertilization as the menstrual cycle transitions into the luteal phase.

次级卵泡会在第二次减数分裂中期停止分裂，并且在卵泡期向黄体期转换的时候等待受精。

More base pairs and more exons mean that there are more chances for mistakes during meiosis, which is when the egg or sperm are being created.

更多的碱基对和外显子意味着减数分裂时有更多出错的可，导致成X染色体上有错误编码序列的卵细胞或者精子。

Typically a gamete with 23 chromosomes, including one sex chromosome either X or Y, develops when parent germ cells undergo the process of meiosis.

正常的配子包含23条染色体，其中有一条X或Y性染色体，由亲代殖细胞减数分裂产。

Now, only if and when an egg fuses with a sperm does it actually complete meiosis II and officially become an ovum.

现在，只有当卵子与精子融合时，才真正完成减数分裂 II 并正式成卵子。

To do this, the primary oocytes have to complete meiosis 1, and in a person's lifetime only about 400 successfully do that.

变成配子就必须经历第一次减数分裂，而一个人的一中大概只有400个初级卵母细胞可以做到。

The LH gets to work on the oocyte that's been dormant inside the follicle, and triggers it to finally start dividing again — getting it to complete meiosis I and move on to metaphase II.

LH 开始作用于卵泡内休眠的卵母细胞，并触发最终再次开始分裂——让完成减数分裂 I 并进入中期 II。

Nondisjunction means the chromosomes don't split apart - so following meiosis, one resulting sex cell ends up with both chromosomes and the other gets none.

不分离意味着染色体没有分开，所以在减数分裂后形成的两个细胞中，一个拥有2条染色体，而另一个一条都没有。

There are two types of cell division: Mitosis and Meiosis.

细胞分裂有两种类型：有丝分裂和减数分裂。

In a secondary follicle, the primary oocyte is still in the prophase step of meiosis 1, but now the follicle has additional layers of granulosa cells, as well as theca cells.

次级卵泡中的初级卵母细胞还是停留在第一次减数分裂前期，而卵泡多了几层颗粒细胞，以及卵泡内膜细胞。

These structures are critical for the process of cell division in next step at meiosis 1.

这些结构对减数分裂 1 的下一步细胞分裂过程至关重。

Remember that the " egg" is still just a secondary oocyte here, and hasn't completed meiosis. As the sperm delivers its payload, it causes a flash of calcium ions from the oocyte's endoplasmic reticulum.

请记住，“卵子”在这里仍然只是一个次级卵母细胞，还没有完成减数分裂。当精子传递其有效载荷时，会从卵母细胞的内质网中产钙离子闪光。

The other option is the sister chromatids of the x chromosome don't separate in meiosis two in the female germ cell.

女性殖细胞中，X染色体姐妹染色单体在第二次减数分裂时没有分离。

Meiosis 2 Meiosis 2 is the second meiotic division and usually involves equational segregation, or separation of sister chromatids.

减数分裂 2减数分裂 2 是减数分裂的第二次分裂，通常涉及相等的分离，或姐妹染色单体的分离。

The first stage lasts from infancy to puberty, and during this stage the primary oocyte remains stuck in the prophase step of meiosis 1.

第一阶段从婴儿期到青春期，初级卵母细胞还停留在第一次减数分裂的前期。

If failure also happens during meiosis in these germ cells as they give rise to gametes, other XXXXY, XXXY and XXYY genotypes that also lead to Klinefelter syndrome can result including the rare situation where there's an additional Y chromosome.

如果有丝分裂和减数分裂均发了不分离，那么这类Klinefelter综合征患者的基因型就可是XXXXY，XXXY和XXYY等，包括了同时多出一条Y染色体的罕见情况。

The oocyte then quickly completes meiosis II, leaving two daughter cells: the large ovum and a puny second polar body.

然后卵母细胞迅速完成减数分裂 II，留下两个子细胞：大卵子和一个微小的第二极体。

Similar to mitosis, cells also pass through the Interphase, G1, S and G2 phase before they enter Meiosis.

与有丝分裂相似，细胞在进入减数分裂之前也经历了间期、G1、S 和 G2 期。

This triggers the primary oocyte within the dominant follicle to finally complete meiosis 1, and turn into a secondary oocyte, which has 23 chromosomes.

这使得优势卵泡里的初级卵母细胞最终完成第一次减数分裂，变成了有23条染色体的次级卵母细胞。