Manipulating sex ratios for conservation: short‐term risks and long‐term benefits
Manipulating sex ratios for conservation: short‐term risks and long‐term benefits
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控制性别比例以进行保护：短期风险和长期收益
DOI：
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发表时间：
2002
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影响因子：
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通讯作者：
Claus Wedekind
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作者：
Claus Wedekind
操纵家庭性别比例通常是可能的，可以通过非侵入性方法，如改变性别决定的生态或社会因素，或通过更具侵入性的方法，如在使用辅助生殖技术之前对胚胎进行激素处理或精子性别鉴定。如果可用卵子的数量限制了人口增长，那么生产的女儿相对多于儿子可能最终会导致人口绝对数量的增长。然而，有效性别比与平等的任何偏差都会增加近亲繁殖率和下一代遗传变异的损失。我在这里表明，存在一系列女性偏向的性别比例，其中人口增长的增加超过了性别比例操纵计划开始后的第一代或前几代内近亲繁殖率提高的影响。在人口规模较小且正在下降的情况下尤其如此，其中一些性别比例操纵不仅增加了有效人口数量 Ne，而且还使人口迅速转变为可以安全抵御阿利效应的人口数量。因此，针对种群遗传质量的最佳性别比例操纵意味着让濒危种群首先通过遗传瓶颈，以实现 Ne 的增加，从而从长远来看降低近亲繁殖率。
Manipulating family sex ratio is often possible, either through non‐invasive methods like changing sex‐determining ecological or social factors, or through more invasive methods such as hormone treatment of embryos or sperm sexing prior to using assisted reproductive technologies. If the number of available eggs limits population growth, the production of relatively more daughters than sons may eventually lead to increased population growth in terms of absolute numbers. However, any deviation of the effective sex ratio from equality increases the rate of inbreeding and the loss of genetic variance in the next generation. I show here that there is a range of female biased sex ratios where increased population growth outweighs the effect of an enhanced inbreeding rate during the first generation or the first few generations after the start of a sex ratio manipulation programme. This is especially so in small and declining populations, where some sex ratio manipulations not only increase the effective population number Ne, but also shift the population quickly into population numbers that are safe against the Allee effect. Consequently, an optimal sex ratio manipulation with respect to the genetic quality of a population means sending an endangered population first through a genetic bottleneck to achieve increased Ne, and hence decreased rates of inbreeding, in the long run.