如果你认为采取人工受精来生孩子很困难,那试试用来生小狗。狗的生殖系统是如此的古怪以至于研究人员从20世纪70年代就开始不断尝试这一方法，却从未成功。但现在，科学家们采用了一套新的技术，成功孕育出世界上第一群“试管小狗”——这是一窝纯种猎犬和混种猎犬幼崽，它们的生命是从一只培养皿中的卵子和精子开始的。为了把这些新幼崽带到这个世界，研究人员从母狗的输卵管等同物中收集了成熟的卵子，这比从卵巢中采集(人类卵子是通过卵巢采集的)更前景难料。研究团队昨天在PLOS ONE报道称，他们一取得卵子就尝试在不同的条件下将它受精和孵化，并最终在代孕母猎犬体中成功诱导7个胚胎发育。研究人员写道，小狗们现在已经5个月大了，并在收养它们的人类家庭中茁壮成长，这给红狼和非洲野狗这样的濒危物种带来了希望。体外受精的狗也可以用来研究遗传特征和疾病，这其中有很多为人类和犬类所共有。

原文链接：Live Births from Domestic Dog (Canis familiaris) Embryos Produced by In Vitro Fertilization

原文摘要：Development of assisted reproductive technologies (ART) in the dog has resisted progress for decades, due to their unique reproductive physiology. This lack of progress is remarkable given the critical role ART could play in conserving endangered canid species or eradicating heritable disease through gene-editing technologies—an approach that would also advance the dog as a biomedical model. Over 350 heritable disorders/traits in dogs are homologous with human conditions, almost twice the number of any other species. Here we report the first live births from in vitro fertilized embryos in the dog. Adding to the practical significance, these embryos had also been cryopreserved. Changes in handling of both gametes enabled this progress. The medium previously used to capacitate sperm excluded magnesium because it delayed spontaneous acrosome exocytosis. We found that magnesium significantly enhanced sperm hyperactivation and ability to undergo physiologically-induced acrosome exocytosis, two functions essential to fertilize an egg. Unlike other mammals, dogs ovulate a primary oocyte, which reaches metaphase II on Days 4–5 after the luteinizing hormone (LH) surge. We found that only on Day 6 are oocytes consistently able to be fertilized. In vitro fertilization of Day 6 oocytes with sperm capacitated in medium supplemented with magnesium resulted in high rates of embryo development (78.8%, n = 146). Intra-oviductal transfer of nineteen cryopreserved, in vitro fertilization (IVF)-derived embryos resulted in seven live, healthy puppies. Development of IVF enables modern genetic approaches to be applied more efficiently in dogs, and for gamete rescue to conserve endangered canid species.