Department of Biology, West Virginia University, WV 26505, USA.
Forensic Sci Int. 2010 Feb 25;195(1-3):63-7. doi: 10.1016/j.forsciint.2009.11.012. Epub 2009 Dec 16.
Lucilia sericata (Diptera: Calliphoridae) is a common urban blowfly, with a worldwide distribution. It is among the most important forensic insects, and a major veterinary pest. A previous amplified fragment length polymorphism (AFLP) survey of Phormia regina, another blowfly, found that the North American population structure results from the fact that flies trapped together at a bait are predominantly comprised of related individuals. We report here a similar population genetic pattern for L. sericata in North America based on AFLP genotypes with 249 loci. A STRUCTURE analysis found no population structure on a geographic scale, and analysis of molecular variance found a moderate amount of variation attributed to samples (adults collected at the same bait at the same time, Phi(SC)=20%, P=0.001). A Mantel test found a negligible correlation between geographic and genetic distances (R(2)=0.0063, P=0.02). The mean relative relatedness coefficient for every sample was positive (mean R=0.2486+/-0.18). Gravid females in a sample, those likely to oviposit on the same corpse, showed a pattern of relatively high relatedness similar to the total survey. Therefore, this pattern of local relatedness is likely to occur with larvae in a corpse, and if so it might support a genetic test for inferring the postmortem relocation of a corpse. This is because a larva may fall from the body at the original scene as it is moved. Connecting such a "stray" larva to the larval population in a corpse would provide powerful evidence that the corpse had been at both locations. Assignment tests resulted in a 96% success rate of assigning L. sericata individuals to their samples of origin.
丝光绿蝇（双翅目：丽蝇科）是一种常见的城市麻蝇，分布于世界各地。它是最重要的法医昆虫之一，也是主要的兽医害虫。之前对另一种麻蝇 Phormia regina 的扩增片段长度多态性（AFLP）调查发现，北美种群结构的原因是在诱饵处一起捕获的苍蝇主要由相关个体组成。我们在这里报告了基于 AFLP 基因型的北美丝光绿蝇的类似种群遗传模式，共有 249 个基因座。STRUCTURE 分析在地理尺度上没有发现种群结构，而基于分子方差的分析发现，有相当一部分变异归因于样本（在同一诱饵处同一时间收集的成虫，Phi(SC)=20%，P=0.001）。Mantel 检验发现地理距离和遗传距离之间存在微不足道的相关性（R(2)=0.0063，P=0.02）。每个样本的平均相对亲缘系数均为正值（平均 R=0.2486+/-0.18）。样本中的怀孕雌蝇，即那些可能在同一尸体上产卵的雌蝇，表现出与总调查相似的相对较高的亲缘关系模式。因此，这种局部亲缘关系模式可能在尸体中的幼虫中发生，如果是这样，它可能支持一种遗传测试，以推断尸体的死后转移。这是因为幼虫可能在尸体被转移时从身体上掉落。将这样的“流浪”幼虫与尸体中的幼虫种群联系起来，将为尸体曾在两个地点提供有力证据。分配测试导致将丝光绿蝇个体分配到其原始样本的成功率达到 96%。
