So you'd think–no yolk, no yolk sac.

所以你会认为我们不需要卵黄，也不需要卵黄囊。

There's an essential ingredient in egg yolks called vitellogenin.

卵黄有一种重要物质叫卵黄生成素。

Inside a chicken egg, the growing embryo produces something called a yolk sac.

在鸡蛋里面，成长胚胎产生一种名为卵黄囊东西。

Unlike birds or turtles, our eggs don't make a yolk, or even a shell.

不像鸟或乌龟，卵子不形成卵黄，甚至外壳。

Humans make an empty yolk sac, and it disappears halfway through pregnancy.

在孕期会产生一个空卵黄囊，但是途就消失了。

Each egg contains one embryo and a yolk sac which the embryo feeds off and helps it develop inside the egg.

每枚卵含有一个胚胎和一个卵黄囊，胚胎从卵黄囊汲取营养，从而得以在卵。

Compared to foragers, these converted workers have higher levels of vitellogenin, a multipurpose protein linked with longevity.

与觅食者相比，这些转变工蚁体内含有更高水平卵黄蛋白原，这是一种与长寿相关多用途蛋白质。

The second subtype is a yolk sac tumor, also called an endodermal sinus tumor, and it's made of germ cells that differentiate into yolk sac tissue.

第二种亚型是卵黄囊瘤，也称为内胚层窦瘤，是由分化为卵黄囊生殖细胞组成。

When her eggs are fertilized, the yolk will provide enough nutrition to keep a growing dinosaur embryo alive for as long as three months.

当它蛋受精后卵黄将会提供充足营养来使恐龙胚胎存活三个月。

It starts with an unfertilized egg cell, added to a blob of yolk, and squeezed down a stretchy tube called an oviduct.

它始于将未受精卵细胞添加到一团卵黄并挤压一个称为输卵管弹性管。

The researchers say that model contains embryonic tissues and other tissues that can produce structures surrounding the embryo, such as the placenta and yolk material.

研究员表示，该模型包含胚胎组织和其他可以在胚胎周围产生结构组织，如胎盘和卵黄物质。

When the hatchlings run out of yolk from their own eggs, they eat the other eggs and hatchlings until one baby shark from each oviduct remains.

当幼体用光了自己卵卵黄，它们就会吃掉其它卵和幼体直到每个输卵管里只剩下一个小鲨鱼。

If we really are descended from animals that once laid eggs full of yolk, can we find some leftover of that yolky gene hidden in human DNA?

如果我们真是从那些下蛋里充满了卵黄动物进化而来，我们能从基因里面找到隐藏卵黄基因遗迹吗？

The four major types of germ cell tumors are: fetal teratomas, both mature cystic and immature teratomas; yolk sac tumors, or endodermal sinus tumor, choriocarcinoma or placental tissue tumors and finally dysgerminomas or oocyte tumors.

4种卵巢细胞癌如下：畸胎瘤，包括成熟囊性畸胎瘤和未成熟畸胎瘤；卵黄囊瘤，又叫内胚窦瘤；绒毛膜癌，又叫胎盘组织肿瘤；最后是无性细胞瘤，又叫卵母细胞瘤。

In 2008, researchers found just that: Fragments of once-active egg yolk genes, hidden in our own genome and when they compared our versions to the chicken versions, they even had the same neighboring genes around them.

2008年 研究员现：他们对比基因片段和鸡基因片段时现，曾经活跃卵黄基因片段就隐藏在我们基因组，它们甚至有相同临近基因。