Sperm, speciation and gene drives in evolution

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Two of the fundamental features of the living world are seemingly invisible in everyday experience: evolutionary change and the DNA of our genomes. But in the lab, rapidly developing animals like the elegant roundworm' C. elegans let us observe real evolution across scores of generations in just weeks. Moreover, the genomic biotechnology revolution of the past decade lets us access root causes of differences between individuals and species, so we can capture a complete genetic snapshot of evolution. What happens when we combine experimental evolution with genome sequencing is biological cinematography: by collecting genomic information over time, we record a genomic movie'. This research aims to record and analyze movies of evolutionary genomic change for C. elegans to test and understand 1) dynamics of new CRISPR/Cas9 gene drive' biotechnology for genetic engineering biocontrol and 2) genomic causes of incompatibility between species that keeps gene pools separate. In parallel, 3) we conduct experiments to understand rapid evolution of a special cell type, sperm cells, that we discovered to cause reproductive barriers between species. By integrating whole-genome analysis with evolution experiments and mechanistic studies, this research makes tangible the abstract foundations of the living world to help explain the origins and maintenance of biodiversity.1. Gene Drive Evolution: New CRISPR/Cas9 gene drive biotech provides an innovative means to fight pest species by engineering their populations for biocontrol, to thwart environmental degradation and improve public health. But release of gene drives into nature presents serious ethical, practical, and environmental concerns. This research will test predictions about gene drive spread across dozens of generations in realistic lab circumstances using C. elegans as an ideal and low-risk model. This real-time study of evolution is crucial to developing evidence-based policy and procedures.2. Speciation Genomics: What genomic changes keep one group of individuals separate from another to create and maintain biodiversity? We use an experimental evolutionary genomics approach, hybridizing two closely-related nematode roundworm species. We then use evolutionary genomic movie-making' to home in on genes that diverged and test how they disrupt genetic networks and developmental programs in hybrids to cause gonad and embryonic defects, yet facilitate proper function within pure species.3. Sperm Evolution: We discovered a fascinating new way that genetic systems can evolve mismatches: sperm cell migration into the body cavity that causes female sterility and death. We are using this convenient cellular microcosm to explore evolutionary cell biology using high-powered microscopy and genetic editing to understand the general evolutionary processes that shape the morphology and behavior of such fundamental cells as gametes.