Data from: Inbreeding depression of sperm traits in the zebra finch Taeniopygia guttata

Inbreeding depression, or the reduction in fitness due to mating between close relatives, is a key issue in biology today. Inbreeding negatively affects many fitness-related traits, including survival and reproductive success. Despite this, very few studies have quantified the effects of inbreeding on vertebrate gamete traits under controlled breeding conditions using a full-sib mating approach. Here, we provide comprehensive evidence for the negative effect of inbreeding on sperm traits in a bird, the zebra finch Taeniopygia guttata. We compared sperm characteristics of both inbred (pedigree F = 0.25) and outbred (pedigree F = 0) individuals from two captive populations, one domesticated and one recently wild-derived, raised under standardized conditions. As normal spermatozoa morphology did not differ consistently between inbred and outbred individuals, our study confirms the hypothesis that sperm morphology is not particularly susceptible to inbreeding depression. Inbreeding did, however, lead to significantly lower sperm motility and a substantially higher percentage of abnormal spermatozoa in ejaculate. These results were consistent across both study populations, confirming the generality and reliability of our findings.近交衰退（inbreeding depression），即近亲交配导致的适合度下降，是当今生物学领域的核心议题之一。近交对诸多与适合度相关的性状存在负面影响，包括生存能力与繁殖成功率。尽管如此，目前极少有研究采用全同胞交配（full-sib mating）方法，在可控繁育条件下量化近交对脊椎动物配子性状的影响。本研究以斑胸草雀（Taeniopygia guttata）为研究对象，为近交对精子性状的负面影响提供了全面的实验证据。我们对比了两个圈养种群（一个为驯化种群，另一个为新近野生来源种群）中，在标准化饲养条件下培育的近交个体（谱系近交系数F=0.25）与远交个体（谱系近交系数F=0）的精子特征。由于近交与远交个体的正常精子形态并无显著一致性差异，本研究证实了精子形态不易受近交衰退影响的假说。但近交确实会显著降低精子活力，并使射精液中异常精子的占比大幅升高。上述结果在两个研究种群中均保持一致，证实了本研究结论的普遍性与可靠性。