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根据红色皇后 (RedOueen)假说的性别决定 ,异体受精应与致病性寄生虫的暴露概率 (即危险度 )正相关。遗憾的是在自然状态下很难对危险度进行测量 ,因此常用感染率代替危险度。但感染率不宜作为风险度的代名词 ,因为取决于自然状态下危险度分析的红色皇后模型可能作出相反的预测。配对等位基因模型提示 :无性种群比有性种群更易感 ,条件是 :①种群中的危险度方差小 ,②危险度均值靠近有利形成有性生殖的选择开关点。但是 ,如果种群中的危险度方差大 ,有性生殖将与感染正相关。此外 ,生殖方式的变异系数在开关点急剧增大。根据上述结果 ,对一种淡水螺Potamopyrgusantipodarum的 95个种群中有关雄性分布的两个研究资料重新进行了分析。结果发现 :螺群中吸虫的感染率方差大 ,而且高度偏态 ;雄性频率同感染力显著正相关 ,生殖方式的变异系数在中等感染水平急剧增大。此外 ,螺群也具备红色皇后假说的必要条件。感染螺群最常见的吸虫是①适于感染本地宿主的 ,②对最近的过去常见的无性种群更具感染力。
According to the sex determination of the Red Queen’s hypothesis, allogeneic fertilization should be positively correlated with the probability of exposure (ie, risk) of the pathogenic parasite. Unfortunately, it is difficult to measure the degree of risk under natural conditions, so the prevalence of infection is often used instead of risk. However, the infection rate should not be used as a synonym for risk because the Red Queen model, which depends on the analysis of the risk in the natural state, may make the opposite prediction. The paired alleles suggest that asexual populations are more susceptible than sexual ones, provided that: (i) the variance in the population is small; (ii) the mean of the risks is close to the point at which a sexual reproduction switch is chosen. However, if there is a large variance in the risk of the population, sexual reproduction will be positively correlated with the infection. In addition, the coefficient of variation of the reproductive method at the switch point increased dramatically. Based on the above results, two studies of male distribution in 95 populations of a freshwater snail, Potamopyrgus antipodarum, were re-analyzed. The results showed that the infection rate of flukes was high and skewed, the male frequency was significantly and positively correlated with the infection, and the coefficient of variation of reproductive style increased sharply at the intermediate infection level. In addition, the spiral group also possesses the necessary conditions of the red queen hypothesis. The most common flukes in a snail population are ① suitable for infection to local hosts, ② more infectious to the most common past asexual populations.