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腾讯登录PLoS Gene：揭示成年雌性动物卵巢中存在前体生殖细胞 仍可分化为卵细胞
| 导读 | 近日，一项针对来自胚胎期的未成熟卵子（卵母细胞）起源的研究为科学界一直以来的争议提供了新的信息，由于女性生物钟的原因，卵母细胞的数量随着其年龄的增加而逐渐减少，而且古代教条主义认为，哺乳动物在产后其卵母细胞并不能够自我更新。刊登在近日的国际杂志<em>PLoS Genetics</em>上的一篇研究报告中，来自麻省总医院和爱丁堡大学的研究者揭示了妇女在其成年生活中依然可以产... |
近日，一项针对来自胚胎期的未成熟卵子（卵母细胞）起源的研究为科学界一直以来的争议提供了新的信息，由于女性生物钟的原因，卵母细胞的数量随着其年龄的增加而逐渐减少，而且古代教条主义认为，哺乳动物在产后其卵母细胞并不能够自我更新。刊登在近日的国际杂志<em>PLoS Genetics</em>上的一篇研究报告中，来自麻省总医院和爱丁堡大学的研究者揭示了妇女在其成年生活中依然可以产生新的卵细胞。
<p align="center"><img src="http://www.bioon.com/biology/UploadFiles/201208/2012081212194040.jpg" alt="" width="237" height="148" border="0" /></p>
卵子是由处于有丝分裂周期的起源生殖细胞（或生殖祖细胞）所产生的，生殖祖细胞通过细胞分裂结束了其增值的能力，最终进入减数分裂期，单一的产生卵细胞和精子。传统观念认为雌性哺乳动物自出生以后就携带有毕生所有的卵细胞了，然而研究者的最新研究表明，成年鼠和人类的卵巢存在有罕见的生殖祖细胞（称为oogonial干细胞），其有能力分化并产生卵母细胞。
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研究者使用了一种强大的遗传工具来追踪随着年龄增长的细胞的分裂过程和数量。如果传统的观念是正确的，所有的细胞分裂应该在出生之前都已经发生了，因此所有的卵细胞应该表现出相同的年龄深度。然而研究结果恰恰相反，随着雌性小鼠的生长，卵细胞的年龄明显增加了。
尽管研究者的研究局限于小鼠之中，但是也提供了明显的证据揭示：oogonial干细胞同样存在于生育年龄的妇女卵巢中，而且这些干细胞拥有完全的能力，可以在实验条件下产生新的卵细胞。当然后期研究者还会进行深入研究来提供更多的证据。
编译自：<a title="" href="http://machineslikeus.com/news/do-ovaries-continue-produce-eggs-during-adulthood" target="_blank">Do ovaries continue to produce eggs during adulthood?</a>
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<a title="" href="http://dx.doi.org/doi:10.1371/journal.pgen.1002848" target="_blank">doi:10.1371/journal.pgen.1002848</a>
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<br/><strong>Oocyte Family Trees: Old Branches or New Stems?</strong><br/>
Dori C. Woods1,2, Evelyn E. Telfer3, Jonathan L. Tilly1,2*
The notion of a “biological clock” in women arises from the fact that oocytes progressively decline in number to the point of exhaustion as females get older, along with a decades-old dogmatic view that oocytes cannot be renewed in mammals after birth [1]. This latter thinking was challenged in 2004 when Tilly and colleagues [2], then others [3], reported that the rate of oocyte loss through follicular atresia and ovulation was much higher than the net rate of oocyte decline. This ignited an ongoing debate about whether the ovaries of adult mammals can form new oocytes and follicles [4]–[6]. Recent work demonstrating that oocyte-producing (oogonial) stem cells (OSCs; also referred to as female germline stem cells or fGSCs) exist in and can be isolated from ovaries of adult fish [7], [8], mice [2], [9]–[11], and even humans [11], [12] has led to new ideas about reproductive biological clocks. Earlier this year, a paper published in PLoS Genetics offered some of the most direct evidence to date that oogenesis in mice continues into adulthood under normal physiological conditions [13].
<br/>来源：生物谷
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<p align="center"><img src="http://www.bioon.com/biology/UploadFiles/201208/2012081212194040.jpg" alt="" width="237" height="148" border="0" /></p>
卵子是由处于有丝分裂周期的起源生殖细胞（或生殖祖细胞）所产生的，生殖祖细胞通过细胞分裂结束了其增值的能力，最终进入减数分裂期，单一的产生卵细胞和精子。传统观念认为雌性哺乳动物自出生以后就携带有毕生所有的卵细胞了，然而研究者的最新研究表明，成年鼠和人类的卵巢存在有罕见的生殖祖细胞（称为oogonial干细胞），其有能力分化并产生卵母细胞。
<!--more-->
研究者使用了一种强大的遗传工具来追踪随着年龄增长的细胞的分裂过程和数量。如果传统的观念是正确的，所有的细胞分裂应该在出生之前都已经发生了，因此所有的卵细胞应该表现出相同的年龄深度。然而研究结果恰恰相反，随着雌性小鼠的生长，卵细胞的年龄明显增加了。
尽管研究者的研究局限于小鼠之中，但是也提供了明显的证据揭示：oogonial干细胞同样存在于生育年龄的妇女卵巢中，而且这些干细胞拥有完全的能力，可以在实验条件下产生新的卵细胞。当然后期研究者还会进行深入研究来提供更多的证据。
编译自：<a title="" href="http://machineslikeus.com/news/do-ovaries-continue-produce-eggs-during-adulthood" target="_blank">Do ovaries continue to produce eggs during adulthood?</a>
<div id="ztload">
<div> </div>
<div>
<div>
<img src="http://www.bioon.com/biology/UploadFiles/201208/2012081212210509.jpg" alt="" width="113" height="149" border="0" />
<a title="" href="http://dx.doi.org/doi:10.1371/journal.pgen.1002848" target="_blank">doi:10.1371/journal.pgen.1002848</a>
PMC:
PMID:
</div>
<div>
<br/><strong>Oocyte Family Trees: Old Branches or New Stems?</strong><br/>
Dori C. Woods1,2, Evelyn E. Telfer3, Jonathan L. Tilly1,2*
The notion of a “biological clock” in women arises from the fact that oocytes progressively decline in number to the point of exhaustion as females get older, along with a decades-old dogmatic view that oocytes cannot be renewed in mammals after birth [1]. This latter thinking was challenged in 2004 when Tilly and colleagues [2], then others [3], reported that the rate of oocyte loss through follicular atresia and ovulation was much higher than the net rate of oocyte decline. This ignited an ongoing debate about whether the ovaries of adult mammals can form new oocytes and follicles [4]–[6]. Recent work demonstrating that oocyte-producing (oogonial) stem cells (OSCs; also referred to as female germline stem cells or fGSCs) exist in and can be isolated from ovaries of adult fish [7], [8], mice [2], [9]–[11], and even humans [11], [12] has led to new ideas about reproductive biological clocks. Earlier this year, a paper published in PLoS Genetics offered some of the most direct evidence to date that oogenesis in mice continues into adulthood under normal physiological conditions [13].
<br/>来源：生物谷
</div>
</div>
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