NSFDEB-NERC: Integrating Computational, Phenotypic, and Population-Genomic Approaches to Reveal Processes of Cryptic Speciation and Gene Flow in Madagascars Mouse Lemurs

Duke University, Durham NC

Investigators

Abstract

Human beings, like all other species, require a healthy environment in order to thrive and, ultimately, survive. Biodiversity — the variety of plants and animals in a given habitat — is the key factor in the health of any environment. We see that biodiversity is presently under extreme threat, however, largely from human impacts such as deforestation and climate change. In order to accurately gauge the nature of that threat, it is essential that scientists establish agreed-upon methods for recognizing the distribution and abundance of species, as well as the mechanism, known as speciation, by which they are formed. This is a complicated task because speciation is usually driven by a complex intersection of biological, geological, and climatological forces. To address this challenge, the project will use an integrated approach that combines computer science, field observation, and genomic analysis to reveal the processes that generate and maintain biodiversity via speciation. The project will focus on an area of Madagascar where habitat fragmentation is threatening the survival of unique and irreplaceable biodiversity. In addition to generating important new knowledge about the processes that drive and delimit speciation, the project will include training and mentorship of students across a range of educational levels. This training is critical for empowering the next generation of conservation scientists so that they can mitigate the environmental challenges that the world faces today and in the years to come. The research focuses on mouse lemurs, which are the world's smallest primates and are unique to Madagascar. These primates are of special biological interest given that they are morphologically and ecologically similar but are genetically highly distinct. This pattern of phenotypic similarity and genetic divergence among species has been observed across the tree of life and is generally referred to as cryptic species diversity. Cryptic species are perplexing to speciation biologists because the indicators of their species identity are hidden to the human eye, thus challenging our ability to accurately measure threatened biodiversity. This project aims to develop and apply a novel and generalizable approach for understanding speciation mechanisms in mouse lemurs specifically, and cryptic species radiations generally. The project builds on current research that indicates that mouse lemurs are highly speciose having experienced episodic bursts of lineage diversification consistent with the climatic cycles of the Pleistocene. Key outcomes of the project will be (1) the development of computational tools for identifying the magnitude, direction, and rate of genetic exchange among lineages, (2) a unique understanding of the roles of ecology, metabolism, and sensory communication for inhibiting reproduction among species, and (3) in those cases where interspecific reproduction occurs, the project will illuminate the role of genomic architecture in compromising the reproductive potential of hybrid individuals. The research will leverage powerful computational innovations for estimating patterns of gene exchange among diverging lineages, new technologies for tracking and monitoring small nocturnal mammals, and methods for applying long-read sequencing technologies for generating genomic resources. Ultimately, this research will help differentiate the effects of natural versus anthropogenic climate change for assessing the health of earth's biodiversity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.