Cryo-storing research lines of chicken to eliminate breeding and save genetic resources

鸟类的繁殖与哺乳动物的繁殖有很大的不同，因此，哺乳动物的繁殖技术不能转移到鸟类身上。发现一种冷冻禽类生殖细胞并随后将禽类带回的方法，将有助于保护濒危家禽品种，增加疾病爆发时的粮食安全，并减少研究中的动物使用。研究用鸡目前在世界各地大量繁殖，以保持种群的遗传多样性，防止近亲繁殖的问题。在其他研究物种中，生殖材料被冷冻以确保未来的可用性，同时减少用于研究的动物数量并保持物种的遗传。此外，当对特定的研究动物有很高的需求，并且创造了许多代时，需要注意确保动物的遗传不会因随机机会而代代不同，这是维持研究动物时常见的问题。我们的项目将验证一项冷冻鸡生殖细胞的新技术，然后从冷冻材料中带回基因多样化的研究群。我们使用来自无菌鸡系的“宿主”鸡蛋，并将来自不同鸡品种的冷冻生殖干细胞转移到这些鸡蛋中。成年鸡外表看起来像不育系，但会产下移植的鸡品种的蛋。如前所述，成年鸟的生殖细胞只会被改变为移植细胞的基因，因此基本上不会受到影响。我们还将考虑将转基因供体鸡细胞引入不育系宿主蛋中，以改善我们所有种畜的整体生活体验。在这个项目中，我们将优化如何冷冻生殖细胞，使用目前保存在罗斯林研究所的三个研究鸡品种。接下来，我们将展示单个代宿主父母可以产下来自许多供体父母的卵子。这一结果将表明，我们将能够带回一个基因多样化的鸡群。最后，我们将展示我们可以从冷冻材料中带回一群纯净的鸡，并将验证鸡群的生育能力和健康状况。有了这些信息，我们将能够自信地对家禽群进行生物库研究。

Avian reproduction differs considerably from mammalian reproduction and therefore, mammalian reproductive technologies are not transferable to birds. Discovering a way to freeze avian reproductive cells and subsequently bring back a flock will help the preservation of endangered breeds of poultry, increase food security from disease outbreaks and reduce animal usage in research.Research chickens are currently bred in large numbers across the world in order to maintain a genetically diverse population and prevent problems with inbreeding. In other research species, reproductive materials are frozen to secure future availability while reducing the numbers of animals used in research and maintaining the genetics of the species. Additionally, when there is a high demand for particular research animals and many generations are created, care is required to ensure that the genetics of the animal don't become different from generation to generation by random chance, which is a common problem when maintaining research animals. Our project will validate a new technology to freeze chicken reproductive cells and later bring back a genetically diverse research flock from the frozen material. We use 'host' eggs from our sterile chicken line and transfer the frozen reproductive stem cells from a different chicken breed into these eggs. The adult bird will look like the sterile line externally, but will lay eggs of the transferred chicken breed. As mentioned previously, the adult birds will only have their reproductive cells changed to the transferred cell's genetics, and therefore will be largely unaffected. We will also look to introducing genetically modified donor chicken cells into the sterile lines host eggs to refine the overall life experience of all our breeding stock. In this project, we will optimise how to freeze the reproductive cells using three research chicken breeds currently kept at the Roslin Institute. We will next show that a single surrogate host parent can lay eggs that come from many donor parents. This result will show that we will be able to bring back a genetically diverse chicken flock. Finally, we will show that we can bring back a pure flock of chicken from frozen material and will verify the fertility and health of the flock. With this information, we will be able to confidently biobank research flocks of poultry.