The lab of Nina Overgaard Therkildsen in the Department of Natural Resources and the Environment at Cornell University invites applications for a PhD position starting in Fall 2026. Our group works...

The 4 year MPhil/PhD provides the opportunity to undertake research accross the full breadth of biological and environmental science. This tailored programme includes taught courses in interdisciplina...

The nature of standing genetic variation remains a central debate in population genetics, with differing perspectives on whether common variants are almost always neutral as suggested by neutral and n...

Imagine you are a kind of fish called a goby, part of a huge family of more than 2,000 species. Maybe you're of average size for a goby, about three to four inches long.

Sexual maturation is a key developmental process important for reproductive success. Understanding the molecular mechanisms behind variation in sexual maturation can provide insights into reproductive biology and how life history variation is encoded in the genome. Atlantic salmon (Salmo salar) has become an excellent sexual maturation research model due to its diversity of life history strategies and its ecological and economic importance. A major challenge has been the lack of a comprehensive transcriptional investigation of reproductive tissues that captures the dynamic transcriptional changes across individuals, tissues, and developmental stages. Long non-coding RNAs (lncRNAs) also play crucial roles in maturation, yet their functions in salmon maturation remain underexplored. In this study, we sequenced 98 transcriptomes and found substantial transcriptomic complexity in the gonad and pituitary tissues of Atlantic salmon. We identified transcripts corresponding to 2,364 putative newly characterized protein-coding genes and 4,421 putative long intergenic non-coding RNAs (lincRNAs), many with tissue-specific expression. Gene co-expression network analysis (WGCNA) revealed tissue-specific gene network modules, linked to GO terms including Wnt signaling in immature testis, lipid metabolism, and cilia assembly in mature testis, ribosome biogenesis and DNA repair in the ovary, and hormone activity in pituitary. We identified new copies of known genes, such as gh1, pou3f2, and ier5 associated with the regulation of gonadal and pituitary functions. Some lncRNAs and their nearest genes showed correlated expression within modules, suggesting potential regulatory roles. Candidate lincRNAs indicated cis-acting regulatory potential on genes like tnfrsf11b and fgl1, which are implicated in immune privilege during gonadal development and sperm quality control. Our study provides a comprehensive transcriptomic analysis of Atlantic salmon gonad and pituitary tissues, significantly improving the functional annotation of the Atlantic salmon genome. These findings reveal key regulatory pathways and novel molecular players involved in sexual maturation, particularly in the testis. Importantly, our study highlights the regulatory potential of lncRNAs in reproductive biology and maturation age variation, advancing our understanding of the molecular mechanisms governing sexual maturation. They further unlock future gene expression analyses and regulatory network reconstruction for dissecting the roles of lncRNAs in Atlantic salmon life history variation.