Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology Trondheim, N-7491, Norway ; Departments of Basic Sciences and Aquatic Medicine, Norwegian School of Veterinary Science PO-8146 Dep, Oslo, N-0033, Norway.
Ecol Evol. 2013 Oct;3(12):4230-42. doi: 10.1002/ece3.819. Epub 2013 Sep 30.
Inbreeding can affect fitness-related traits at different life history stages and may interact with environmental variation to induce even larger effects. We used genetic parentage assignment based on 22 microsatellite loci to determine a 25 year long pedigree for a newly established island population of moose with 20-40 reproducing individuals annually. We used the pedigree to calculate individual inbreeding coefficients and examined for effects of individual inbreeding (f) and heterozygosity on fitness-related traits. We found negative effects of f on birth date, calf body mass and twinning rate. The relationship between f and calf body mass and twinning rate were found to be separate but weaker after accounting for birth date. We found no support for an inbreeding effect on the age-specific lifetime reproductive success of females. The influence of f on birth date was related to climatic conditions during the spring prior to birth, indicating that calves with a low f were born earlier after a cold spring than calves with high f. In years with a warm spring, calf f did not affect birth date. The results suggest that severe inbreeding in moose has both indirect effects on fitness through delayed birth and lower juvenile body mass, as well as separate direct effects, as there still was a significant relationship between f and twinning rate after accounting for birth date and body mass as calf. Consequently, severe inbreeding as found in the study population may have consequences for population growth and extinction risk.
近亲繁殖会影响不同生命史阶段与适应度相关的特征，并且可能与环境变化相互作用，从而产生更大的影响。我们使用基于 22 个微卫星位点的遗传亲子关系分配来确定一个新建立的 25 年历史的驼鹿岛屿种群的系谱，该种群每年有 20-40 只繁殖个体。我们使用系谱来计算个体近亲系数，并研究个体近亲系数（f）和杂合性对与适应度相关的特征的影响。我们发现 f 对出生日期、牛犊体重和双胞胎率有负面影响。在考虑出生日期后，f 与牛犊体重和双胞胎率之间的关系被发现是分开的，但较弱。我们没有发现 f 对雌性特定年龄终生生殖成功有影响。f 对出生日期的影响与出生前春季的气候条件有关，这表明在寒冷的春季，f 值较低的小牛比 f 值较高的小牛出生更早。在温暖的春季，牛犊 f 不会影响出生日期。研究结果表明，驼鹿的严重近亲繁殖既有通过延迟出生和降低幼体体重的间接适应度影响，也有直接影响，因为在考虑出生日期和体重作为小牛后，f 与双胞胎率之间仍然存在显著关系。因此，研究种群中发现的严重近亲繁殖可能会对种群增长和灭绝风险产生影响。
