Parasitic lice as markers of modern and archaic human introgression

早期人类进化的模式是一个引人注目的研究课题。化石和基因数据为人类历史提供了深刻的见解。然而，还有许多重要的问题没有得到解答。最近的研究发现了现代人类中尼安德特人基因的证据。科学家们已经证明，这种共享的DNA是现代人和尼安德特人在时间和空间上重叠的时期杂交的结果。科学家们无法确定的是这种杂交的具体时间，地点和社会背景。人类基因数据不允许我们区分短暂的事件和长期的杂交。然而，生活在不同人群身上的不同虱子群体应该保持不同，除非这些人群有长期和亲密的接触。因此，这项研究将使用虱子基因来确定这些人类在遥远的过去何时，何地以及持续多久的密切接触。 研究人员将从北方非洲和中东的人群中收集虱子，那里被认为是人类与尼安德特人融合的第一次发生。这些虱子的遗传数据将被收集和检查，以探索人类进化的模式。该项目将培训本科生，研究生和博士后研究人员如何有效地将研究成果传达给广大受众。研究团队还将帮助博物馆促进中学生和高中生的科学素养。人类虱子（Pedicularis humanus）的DNA变异模式证实了现已灭绝的人类（如尼安德特人和现代人类）之间的相互作用。此外，这两种宿主的虱子之间的杂交证据甚至比我们在宿主身上看到的还要多。来自90个关键地理种群的广泛地理范围内的虱子样本的基因组采样增加将允许改进尼安德特人和现代人之间相互作用的位置和性质的建模。使用佛罗里达大学的高性能计算机集群（HiPerGator），将根据在90个种群中观察到的大约10，000个P. humanus基因的特征生成合并模拟。近似贝叶斯计算将用于确定人类行为的时间模型最适合生成的数据。

The pattern of early human evolution is a compelling topic for study. Fossil and genetic data provide deep insights into human history. Yet there are many important questions left unanswered. Recent research has found evidence of Neanderthal genes in modern humans. Scientists have shown that this shared DNA resulted from interbreeding during periods where modern humans and Neanderthals overlapped in time and space. What scientists have not been able to do is determine are the specific times, places and social context of this interbreeding. The human genetic data does not allow us to differentiate brief events from prolonged interbreeding. However, the distinct populations of lice that live on different human populations should remain distinct unless those human populations have prolonged and intimate contact. Therefore, this research will use louse genes to determine when, where, and for what duration these humans were in close contact in the distant past. The researchers will collect lice from populations in northern Africa, and the Middle East where human introgression with Neanderthals is thought to have first occurred. Genetic data from these lice will be collected and examined to explore patterns of human evolution. This project will train undergraduate students, graduate students, and a postdoctoral researcher how to effectively communicate research findings to broad audiences. The research team will also help museums promote scientific literacy in Middle School and High School students. Patterns of DNA variation in the Human Louse (Pedicularis humanus) confirm interactions between now-extinct humans such as Neanderthal and Modern humans. Further, there is even greater evidence of interbreeding between the lice of these two hosts than we see in the hosts themselves. Increased sampling of genomes across a broad geographic range of Louse samples from 90 key geographic populations will allow improved modeling of the location and nature of interactions between Neanderthal and Modern humans. Coalescent simulations will be generated based on the observed characteristics of roughly 10,000 P. humanus genes in 90 populations using the University of Florida's high-performance computer cluster (HiPerGator). Approximate Bayesian Computation will be used to determine what model of human behavior across time best fits the data that is generated.