亲缘关系对于金丝猴后宫社会形成的作用研究

【作者】 何刚；

【导师】 李保国；

【作者基本信息】 西北大学 ， 动物学， 2013， 博士

【摘要】 动物的社群稳定机制是研究其生存策略的突破口,其中采食策略和婚配制度是组成其稳定机制的两个主要方面,在川金丝猴种群中,两者均与其社群组织密不可分。秦岭川金丝猴是以一雄多雌后宫式的家庭单元构成社会组织,其中单元内的雄性常被替换,而雌性则相对稳定。这种稳定的后宫对其家庭单元的稳定,进而对整个社群的稳定意义重大,是研究金丝猴稳定机制的重要内容和关键问题。另一方面,亲缘关系是影响动物婚配制度和社群组织的关键因素之一。那么单元内的雌性为什么能够长期、稳定的组合生活在一起?为了回答这一问题,本文检验了亲缘关系对金丝猴后宫的形成是否产生影响,检验了亲缘关系对雌性的单元间迁移是否产生影响。本文在个体识别的基础上,采集了秦岭玉皇庙西梁群川金丝猴的非损害性样品,利用多态性微卫星位点计算个体间的亲缘系数,并对比了不同组别(根据单元归属以及性别进行分组)间的亲缘系数,探讨亲缘关系如何影响川金丝猴的后宫社会、迁移策略以及社会组织。本研究主要获得以下结果：1.对比研究了计算亲缘系数的矩估计法和最大似然法,经过计算比较,其中Lynch&Ritland(1999)模型在综合考虑其估计亲子、全同胞、半同胞和无关个体时的方差较小(6分别为0.0236,0.0344,0.0350,0.0256),较为适合本研究,所以选用该模型计算亲缘系数。2.使用来源于秦岭多个地区的“秦岭川金丝猴群体”的样品,从144个已报道的非人灵长类微卫星位点中筛选出52个具有多态性的位点,作为候选位点拟用于亲缘系数计算。应用非损害性采样方法,分3个采样期(分别为2005、2008和2011年),对秦岭周至国家自然保护区西梁群采样,共采集了86个成年个体,共131份非损害性毛发和粪便样品。结合前期多态性位点的研究,挑选18个在西梁群中多态性最高的位点进行所有样品的扩增分型,并通过至少2次的重复扩增以保证分型的正确率。结果,除一个位点外其他17个位点均符合哈温平衡,等位基因数为3.8889±0.7370(平均值±标准差,下同),表观杂合度0.6179±0.0883,期望杂合度0.6261±0.0601,多态信息含量0.5572±0.0703,有效等位基因数2.7514±0.4933,近交系数FIS=0.0118±0.1214,结果表明该研究群体的遗传多样性水平处于较高的水平且近交水平较低。3.根据分型结果,计算西梁群个体间的亲缘系数,依据个体的单元、性别进行个体对分组,对不同组别的亲缘系数进行比较。发现单元内雌性与群体内雌性之间的亲缘系数存在显著差异(P<0.0001,Z=4.7170),提示单元内雌性川金丝猴的组合与稳定存在明显的亲选择；单元内的雌性个体亲缘系数明显高于群体内的(F-F in OMU (?)r=0.0673,F-F in Troop (?)r=-0.0049),说明雌性个体明显存在倾向于同其雌性亲属(或亲缘关系更近的雌性个体)生活在一个单元中的现象。4.对迁移个体的迁移目标单元与可选单元的亲缘系数进行比较,结果发现雌性个体在单元间迁移时将选择与其雌性亲缘关系较近的单元迁入(P=0.0056,Z=-2.7685),而对单元主雄的选择性不明显(P=0.9274,Z=0.0911)。5.对群体中雌雄两种性别分组数据进行Fisher’s检验(fisher’s extract test),结果显示两性中的等位基因和基因型的分布均存在显著差异(等位基因分布：Χ2=59.64,P=0.0042；基因型分布：Χ2=58.03,P=0.0063)；对每个位点都进行了G检验(extract G-test),结果显示等位基因和基因型的分布在D7s2204,D19s248, TPOX和D16s540这4个位点表现出了显著的差异(α=0.05),提示某一性别的个体存在外来迁入个体。结合金丝猴的生活史,推测雄性个体进行群间迁移的可能性最大,AMU极有可能是猴群之间进行基因交流的桥梁。更多还原

【Abstract】 The group stability mechanism is the breach of researching the survival strategy of animals, where the mating system and foraging strategy are the two key factors of the group stability mechanism. In Sichuan snub-nosed monkey (Rhinopithecus roxellana), they both are inseparable to the social organization. The basic unit of R. roxellana society consist of one adult male, serveral adult female and their offsprings. The resident male of a unit is often replaced, but the female is relatively stable. This kind of harem is meaningful to the stability of units and troop, and becomes a key issue in researching the group stability mechanism of R. roxellana.On the other hand, kinship is one of the key factors of mating system and social organization of animal. How can female monkeys in a same unit live together long and stable? In order to answer this question, and test if relatedness influence the harem of R. roxellana, and test if relatedness influence the dispersal of females between units, I collect the noninvasive genetic samples from monkeys in West Ridge Troop on the basis of individual identification. The pairwised relatedness coefficient is obtained from microsatellite genotype data, and the relatedness coefficient of different categories classified by unit and gender are compared to study how does the relatedness influence the harem system of R. roxellana, dispersal strategy and social organization. The main results are as follows:1. Compared the effectiveness of method of moment and maximum likelihood in estimating relatedness. By computer simulation, Lynch&Ritland (1999) estimator yield least variance in comprehensive consideration of parent-offspring, full-sibs, half-sibs and unrelated, the variance of corresponding relationship is0.0236,0.0344,0.0350and0.0256. It meet the demands of this study and is selected for estimating relatedness.2.131adult samples and86individuals were collected from West Ridge Troop in ZhouZhi National Nature Reserve by3study periods (in year2005,2008and2011). Fifty-two polymorphic microsatellite loci were segregated from144reported loci in non-human primate using samples from serveral locations in Qinling mountains. And18most polymorphic loci from which were select for this study. Genotype of each individual at each loci was obtain from at least two positive amplification to make sure the correct genotype rate reaches99%. The number of alleles is3.8889±0.7370(mean±SD), observed heterozygosity is0.6179±0.0883, expected heterozygosity is0.6261±0.0601, PIC is0.5572±0.0703, effective number of alleles is2.7514±0.4933, inbreeding coefficient Fls=0.0118±0.1214. All loci were according to the Hardy-Weinberg Equilibrium except D13s321which were exclude from further analysis. These result indicate that the genetic diversity of WRT was in a high level, while the inbreeding level is low.3. According the genotype data, the pairwised relatedness coefficient was calculated. The individual dyads were classified into6categories according to the unit and gender (female-female within unit, female-female within troop, female-male within unit, female-male within troop, male-male within troop, all dyads). By comparing the median of relatedness in different categories, I found that the relatedness of females within unit is significantly different from that that within troop (P<0.0001, Z=4.7170), and the mean relatedness of females within unit is higher than that within troop (F-F in OMU r=0.0673, F-F in Troop r=-0.0049). This result indicate significant kin selection in female monkeys in unit organization, and female kins are prefer to live in a same unit.4. By comparing the destiny and candidate units of dispersing female monkeys, I found female selective disperse into the unit consist her female relatives (P=0.0056, Z=-2.7685), but the selectivity of resident male was not significant (P=0.9274, Z=0.0911).5. Fisher’s test was performed to test whether the genotypes and alleles in males and females were drawn from the same distribution. And the results illustrate that their distribution were significantly different (alleles:χ2=59.64, P=0.0042; genotypes: χ2=58.03, P=0.0063). And extract G-test was performed for each locus, and I found the genotypes and alleles in males and females were drawn from the different distribution at four loci (D7s2204, D19s248, TPOX and D16s540, a=0.05). Which showed there are a large proportion in one of the two gender were migrants, and integrating the field observation data, I infer that the male individuals are more possible to dispersal among troops, and AMU may be the bridge of gene flow between troops.更多还原