West Stuart A, Buckling Angus
Institute of Cell, Animal and Population Biology, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh EH9 3JT, UK.
Proc Biol Sci. 2003 Jan 7;270(1510):37-44. doi: 10.1098/rspb.2002.2209.
Kin selection theory predicts that the damage to a host resulting from parasite infection (parasite virulence) will be negatively correlated to the relatedness between parasites within the host. This occurs because a lower relatedness leads to greater competition for host resources, which favours rapid growth to achieve greater relative success within the host, and that higher parasite growth rate leads to higher virulence. We show that a biological feature of bacterial infections can lead to the opposite prediction: a positive correlation between relatedness and virulence. This occurs because a high relatedness can favour greater (cooperative) production of molecules that scavenge iron (siderophores), which results in higher growth rates and virulence. More generally, the same underlying idea can predict a positive relationship between relatedness and virulence in any case where parasites can cooperate to increase their growth rate; other examples include immune suppression and the production of biofilms to aid colonization.
亲缘选择理论预测，寄生虫感染对宿主造成的损害（寄生虫毒力）将与宿主体内寄生虫之间的亲缘关系呈负相关。出现这种情况的原因是，较低的亲缘关系会导致对宿主资源的竞争加剧，这有利于快速生长以在宿主体内取得更大的相对成功，而较高的寄生虫生长速率会导致更高的毒力。我们发现，细菌感染的一个生物学特征会导致相反的预测结果：亲缘关系与毒力之间呈正相关。出现这种情况的原因是，高度的亲缘关系可能有利于更多地（协同）产生用于 scavenge iron（铁载体）的分子，这会导致更高的生长速率和毒力。更一般地说，在任何寄生虫能够通过合作提高其生长速率的情况下，相同的基本观点都可以预测亲缘关系与毒力之间存在正相关；其他例子包括免疫抑制以及产生生物膜以帮助定殖。 （注：“scavenge iron”字面意思是“清除铁”，在生物学语境中可能有更专业准确的表述，这里直接保留英文以便读者根据专业知识理解其确切含义。）
