Andy is a PhD Candidate in the Gagnon Lab where she researches the roles of individual germline stem cells during adult tissue homeostasis in zebrafish. She has been an NIH Developmental Biology Training Grant fellow since October of 2019. Originally from Nevada, Andy moved to Tucson, AZ where she received her B.S. in Molecular and Cellular Biology at the University of Arizona. Under her advisor, Dr. Eric Lyons, she researched the evolutionary history of HID1 long non-coding RNAs in the Brassicaceae family. When she isn’t in the lab or riding her road bike, Andy enjoys painting and watching good films.
Stem cells contribute to tissue homeostasis in adult organisms by re-deploying embryonic differentiation and cell signaling mechanisms. However, it is difficult to trace individual stem cells in their native context and understand stem cell contributions or competition during organ development. Zebrafish spermatogonial stem cells (SSCs) in the testis maintain an active stem cell population over the lifetime of the animal, while also producing differentiated sperm. To determine the roles of individual stem cells during spermatogenesis, we used CRISPR-Cas9 to generate DNA barcodes that label individual SSCs and their descendants. These lineage barcodes can be expressed and recovered along with the transcriptome using single-cell RNA sequencing. Using 10X Chromium single-cell RNA sequencing, we identified transcriptional profiles of a variety of somatic and germline cell types in the testis and captured a snapshot of SSC contributions to differentiated cells during spermatogenesis. We also sequenced the lineage barcodes associated with 84% of these cells across all cell type clusters, a dramatic improvement from our previous CRISPR lineage tracing methods. Up to three gonads may exist in one zebrafish over its lifetime. In the future, I will compare cell atlases among these gonad types and trace germline stem cells during an ovary-to-testis transition.