Lewis K
Biotechnology Center, Tufts University, Medford, MA 02159, USA.
J Theor Biol. 1998 Jul 27;193(2):359-63. doi: 10.1006/jtbi.1998.0725.
It is suggested that pathogen and parasite avoidance act as a driving force for kin selection. Preferential association with relatives decreases the probability of infection with unfamiliar pathogens. Altruistic behavior towards kin will further decrease the danger of infection by increasing the representation of relatives in a group. Such a behavioral strategy could evolve if pathogen resistance were heritable. Highly polymorphic major histocompatibility (MHC) genes largely determine heritable resistance to particular pathogens. The degree of relatedness within a group correlates with the degree of similarity in MHCs. It has been shown that detection of MHC type by mice guides preferential kin association. Pathogen avoidance appears to be the simplest explanation for the existence of a direct link between detecting the heritable component of the immune system and kin altruism. Detection of MHC also serves kin avoidance in mating. Periodic introduction of new genes including MHCs through mating provides resistance to the unavoidable appearance of foreign virulent pathogens (Hamilton et al., 1990, Proc. Natl Acad. Sci. U.S.A. 87, 3566-3573). It is suggested that kin preference favoring homogeneity punctuated by introduction of new genes through mating provides an optimal strategy for pathogen avoidance. Aggression might also serve to decrease infection by isolating or eliminating individuals with unrelated MHCs.
有人认为，避免病原体和寄生虫是亲缘选择的驱动力。与亲属的优先交往降低了感染不熟悉病原体的概率。对亲属的利他行为通过增加亲属在群体中的比例，将进一步降低感染的危险。如果病原体抗性是可遗传的，那么这样一种行为策略就可能进化。高度多态的主要组织相容性（MHC）基因在很大程度上决定了对特定病原体的可遗传抗性。群体内的亲缘程度与MHC的相似程度相关。研究表明，小鼠对MHC类型的识别引导着优先的亲缘交往。病原体回避似乎是免疫系统的可遗传成分检测与亲缘利他行为之间存在直接联系的最简单解释。MHC的检测在交配中也有助于避免近亲繁殖。通过交配定期引入包括MHC在内的新基因，可提供对不可避免出现的外来致病病原体的抗性（汉密尔顿等人，1990年，《美国国家科学院院刊》87卷，3566 - 3573页）。有人认为，通过交配引入新基因以打破同质性从而偏向亲缘偏好，这为病原体回避提供了一种最优策略。攻击行为也可能通过隔离或消除具有不相关MHC个体来减少感染。
