DISSERTATION RESEARCH: Reassessing the role of the Great American Biotic Interchange in the evolution of the raccoon family

美洲生物大交换(Gabi)是一项重大的生物地理事件，通过巴拿马地峡的关闭连接了北美和南美洲的陆地动物群。地质证据和化石记录表明，地峡的关闭发生在300万年前(Mya)，但最近的研究表明，北美和南美洲之间形成陆桥的年龄要早得多，约为15 Mya。在起源于北美的哺乳动物中，浣熊科(原浣熊科)，也包括Coatis，kinkajous，olingos和Ringtails，在南美洲拥有最长的历史之一。化石记录显示，这一群体中已灭绝的一种成员是第一个移民到南美洲的北美哺乳动物，大约7-9英里。虽然流行的假说表明，这一群体的现代成员的移民发生在3mya，但最近基于DNA序列数据的估计显示，这个家庭在南美洲的居住时间要长得多。这项研究将更彻底地检验关于这一群体进化过程和时间的相互竞争的假说，有可能修正我们对新热带地区哺乳动物进化的理解，同时促进基因组学、系统学、分类学和生物地理学领域的进步，以及促进职业生涯早期的女性STEM研究人员的专业发展。这个项目将使用一种综合的方法来检验基于博物馆标本的基因组分析、形态计量学和生物地理建模的相互竞争的假说。古代DNA技术与高通量测序方法相结合，将被用于对线粒体基因组进行排序，以及使用一种新的内含子捕获微阵列来采样核基因组。形态测量学数据将单独分析，并与比较基因组数据一起分析，以检验关于原胞体进化的假设，并修改这一组的分类学。一个包含最新DNA和地质证据的浣熊家族进化的新生物地理模型将与传统的基于化石的假说进行对比测试，并将整合系统发育数据，以重新评估与Gabi相关的多样化的速度和地理模式。结果将通过由PI、共同PI和合作者共同撰写的科学出版物共享。分析中使用的基因组和形态数据、方案、脚本和参数将通过NCBI、S基因库和Dryad的电子存储库公开提供。

The Great American Biotic Interchange (GABI) was a major biogeographic event that connected the terrestrial animal communities of North and South America via the closure of the Panamanian Isthmus. Geological evidence and the fossil record have suggested that the closure of the isthmus occurred 3 million years ago (mya), but more recent studies suggest a much older age for the formation of a landbridge between North and South America, around 15 mya. Among mammals of North American origin, the raccoon family (Procyonidae), which also includes coatis, kinkajous, olingos, and ringtails, has one of the longest histories in South America. The fossil record shows that an extinct member of this group was the first North American mammal to immigrate to South America, approximately 7-9 mya. While the prevailing hypothesis states that immigration of modern members of this group took place 3 mya, recent estimates based on DNA sequence data revealed that this family has had a much longer tenure in South America. This study will more thoroughly test competing hypotheses regarding the process and timing of evolution of this group, with the potential to revise our understanding of mammal evolution in the Neotropics, while contributing to advancement in the fields of genomics, systematics, taxonomy, and biogeography, as well as promoting the professional development of an early-career female STEM researcher. This project will use an integrative approach to test competing hypotheses based on genomic analyses of museum specimens, morphometrics, and biogeographic modeling. Ancient DNA techniques in combination with high-throughput sequencing methods will be used to sequence mitochondrial genomes as well as to sample the nuclear genome using a novel intron-capture microarray. Morphometric data will be analyzed separately and in conjunction with comparative genomic data to test hypotheses regarding procyonid evolution and revise the taxonomy of this group. A new biogeographic model for the evolution of the raccoon family that accommodates the most recent DNA and geological evidence will be tested against the traditional fossil-based hypothesis, and will integrate phylogenetic data to reassess the tempo and geographic pattern of diversification associated with the GABI. Results will be shared through scientific publications co-authored by the PI, Co-PI, and collaborators. Genomic and morphological data, protocols, scripts and parameters used in the analyses will be made publicly available through the electronic repositories of NCBI?s Genbank and Dryad.