Johnston L A, Lacy R C
Henry Doorly Zoo, Omaha, Nebraska 68107.
Cryobiology. 1995 Feb;32(1):68-77. doi: 10.1006/cryo.1995.1006.
The systematic banking of genome resources using cryopreserved germ plasm offers the opportunity to further conservation strategies of endangered species by assisting in the effective genetic management of captive populations. Cryopreserved germ plasm will allow indefinite preservation of the presently available gene diversity represented in either captive or wild populations. If properly utilized, genome resource banks have the potential to decelerate the loss of gene and allelic diversity in captive populations through reintroducing "original" genetic material through time to counter genetic drift. However, in order for any genome resource bank to be effective, strategies need to be developed to identify genetically valuable individuals to bank which will represent optimal gene diversity of the specific population. Four selection strategies were evaluated to identify individual donors from four North American captive populations representing differently structured pedigrees. The strategies consisted of selecting: (1) all males in the population ("All Male Bank"); (2) only living founders and early generation descendents ("Founder Method Bank," FMB); (3) males remaining after culling to minimize mean kinship ("Culled Male Bank 1"); and (4) males remaining after culling to minimize mean kinship, with the males reduced to the number in the FMB ("Culled Male Bank 2"). The effectiveness of each strategy was based on the comparison of genetic variation metrics in each bank with the genetic variation in the present living managed population. Although maximal retention of allelic diversity was achieved by banking genes from all living animals, nearly optimal retention of allelic and gene diversity was obtained by utilizing the selection strategy based on minimizing mean kinships. As a consequence, properly designed and utilized, genome resource banks can become effective tools for preserving gene diversity in future generations of living populations.
利用冷冻保存的种质对基因组资源进行系统存储，为濒危物种的进一步保护策略提供了契机，有助于对圈养种群进行有效的遗传管理。冷冻保存的种质能够无限期保存目前圈养或野生种群中所代表的基因多样性。如果得到妥善利用，基因组资源库有潜力通过适时重新引入“原始”遗传物质来对抗遗传漂变，从而减缓圈养种群中基因和等位基因多样性的丧失。然而，为了使任何基因组资源库发挥有效作用，需要制定策略来识别具有遗传价值的个体进行存储，这些个体应代表特定种群的最佳基因多样性。我们评估了四种选择策略，以从四个具有不同谱系结构的北美圈养种群中识别个体供体。这些策略包括选择：（1）种群中的所有雄性个体（“全雄库”）；（2）仅现存的奠基者和早期后代（“奠基者方法库”，FMB）；（3）剔除后剩余的雄性个体，以使平均亲缘关系最小化（“剔除雄库1”）；以及（4）剔除后剩余的雄性个体，以使平均亲缘关系最小化，且数量减少至FMB中的数量（“剔除雄库2”）。每种策略的有效性基于将每个库中的遗传变异指标与当前存活的管理种群中的遗传变异进行比较。尽管通过存储所有现存动物的基因可实现等位基因多样性的最大保留，但利用基于最小化平均亲缘关系的选择策略可获得近乎最佳的等位基因和基因多样性保留。因此，经过合理设计和利用，基因组资源库能够成为保护现存种群后代基因多样性的有效工具。
