Selective breeding and genetic modification have been the cornerstone of animal agriculture. However, the current strategy of breeding animals over multiple generations to introgress novel alleles is not practical in addressing global challenges such as climate change, pandemics, and the predicted need to feed a population of 9 billion by 2050. Consequently, genome editing in zygotes to allow for seamless introgression of novel alleles is required, especially in cattle with long generation intervals. We report for the first time the use of CRISPR-Cas genome editors to introduce novel PRNP allelic variants that have been shown to provide resilience towards human prion pandemics. From one round of embryo injections, we have established six pregnancies and birth of seven edited offspring, with two founders showing >90% targeted homology-directed repair modifications. This study lays out the framework for in vitro optimization, unbiased deep-sequencing to identify editing outcomes, and generation of high frequency homology-directed repair–edited calves.

中文翻译：

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合子中一步同源性介导的 CRISPR-Cas 编辑用于生成基因组编辑的牛

选择性育种和基因改造一直是畜牧业的基石。然而，目前通过多代繁殖动物以渗入新等位基因的策略在应对气候变化、流行病以及预计到 2050 年需要养活 90 亿人口等全球性挑战方面并不实用。允许新等位基因的无缝渗入是必需的，特别是在具有长世代间隔的牛中。我们首次报告使用 CRISPR-Cas 基因组编辑器引入新的PRNP已被证明对人类朊病毒大流行具有复原力的等位基因变体。从一轮胚胎注射中，我们已经建立了 6 次怀孕和 7 次编辑后代的出生，其中两名创始人显示出 >90% 的靶向同源性修复修饰。本研究为体外优化、无偏深度测序以识别编辑结果以及生成高频同源定向修复编辑小牛制定了框架。