Crabbe J C, Schneider U, Hall J W, Mazur P
Research Service, Department of Veterans Affairs Medical Center, Portland, Oregon 97201.
Behav Genet. 1993 Jul;23(4):307-12. doi: 10.1007/BF01067430.
Cryopreserved embryos should survive centuries. Upon rederivation, in vitro survival is high. Upon reimplantation, in vivo survival is substantial. Genetic stability of the embryos at -196 degrees C is theoretically absolute for several decades and likely high for centuries. Cryopreservation and rederivation services are available at a reasonable cost from commercial vendors. Preservation of a sufficient number of embryos can serve as an insurance policy against loss of the lines from several causes. In addition to the protective utility of a single banked sample, repeated preservation during the course of selection offers several advantages. Correlated responses to selection which appear late in selection may be verified by use of a cross-sectional experimental design to take a "snapshot" of the gradually developing response. After attainment of the selection limit, a generation may be chosen retrospectively which represents the best compromise between maximizing response and minimizing inbreeding irrelevant to the selected trait. Estimates of changes in gene frequencies could be derived from molecular biological analyses. An example of such an experiment in progress employing embryos from the COLD and HOT selected mouse lines is discussed.
冷冻保存的胚胎应该能存活数百年。重新衍生后，体外存活率很高。重新植入后，体内存活率也相当可观。胚胎在-196摄氏度下的遗传稳定性理论上在几十年内是绝对的，在几个世纪内可能也很高。商业供应商提供冷冻保存和重新衍生服务，成本合理。保存足够数量的胚胎可以作为一种保险政策，防止因多种原因导致品系丢失。除了单个保存样本的保护作用外，在选择过程中重复保存还有几个优点。在选择后期出现的对选择的相关反应，可以通过使用横断面实验设计来“抓拍”逐渐发展的反应进行验证。达到选择极限后，可以回顾性地选择一代，这一代代表了在最大化反应和最小化与所选性状无关的近亲繁殖之间的最佳折衷方案。基因频率变化的估计可以从分子生物学分析中得出。讨论了一个正在进行的此类实验的例子，该实验使用了来自COLD和HOT选择的小鼠品系的胚胎。
