Additive genetic variance (V_A) reflects the potential for evolutionary shifts and can be low for some traits or populations. High V_A is critical for the conservation of threatened species under selection to facilitate adaptation. Theory predicts tight associations between population size and V_A, but data from some experimental models, and managed and natural populations do not always support this prediction. However, V_A comparisons often have low statistical power, are undertaken in highly controlled environments distinct from natural habitats, and focus on traits with limited ecological relevance. Moreover, investigations of V_A typically fail to consider rare alleles, genetic load, or linkage disequilibrium, resulting in deleterious effects associated with favored alleles in small populations. Large population size remains essential for ensuring adaptation.

加性遗传方差（V _A）反映了进化变化的可能性，对于某些性状或种群而言可能较低。高V_一个是至关重要的濒危物种的选择下养护，以促进适应。理论上可以预测种群数量与V _A之间的紧密联系，但是来自某些实验模型的数据以及受管理的种群和自然种群并不总是支持这一预测。然而，V_一个比较通常具有较低的统计力量，以高度受控的环境中自然栖息地的不同，并注重与有限的生态相关性状进行。此外，V的调查_一通常不会考虑稀有的等位基因，遗传负荷或连锁不平衡，从而导致与少数人群中偏爱的等位基因相关的有害影响。人口众多对确保适应至关重要。