Expression and elimination of the zebra finch germline-restricted chromosome

Vontzou, Niki (2025) Expression and elimination of the zebra finch germline-restricted chromosome. Doctoral thesis, University of East Anglia.

PDF Restricted to Repository staff only until 30 October 2028. Request a copy

Abstract

Life cycles of multicellular organisms are formed by predetermined and stochastic cell fate decisions that usually reflect a complex interplay of synergistic and antagonistic interactions. In some organisms, these interactions are reshaped by the phenomenon of programmed DNA elimination (PDE). The discovery of the developmental and evolutionary dynamics of PDE has recently started gaining ground following the advances in high-throughput sequencing technologies. Among these discoveries, passerines, representing two thirds of all ~11,000 bird species, were shown to undergo PDE, where a so-called germline-restricted chromosome (GRC) is eliminated by somatic cells during early embryogenesis; yet the exact mechanistic and temporal framework of the elimination remain elusive. Passerine GRCs could constitute a novel system to comprehensively study the roles of PDE in the germ cell fate and disentangle its molecular consequences in germline/soma dichotomy. In this thesis, I use zebra finch as a model system of passerine PDE and an interdisciplinary combination of state-of-the-art technologies. After outlining the potential involvement of the GRC in genetic conflicts, I pinpoint key developmental time points with distinct GRC expression profiles. Then, using live-embryo imaging, I identify the spatiotemporal onset of PDE in the early zebra finch embryo. Finally, I provide a miRNA-guided mechanistic framework that may drive PDE in the early zebra finch cleavage. Collectively, I highlight the involvement of GRC in the promotion of germ cell dual capacity for self-renewal and differentiation throughout the germline life cycle and provide evidence supporting GRC-linked co-option to a germline-specific developmental program. These findings could serve as a breeding ground for reevaluating cell fate transitions and exploring the multiplicity of evolutionary and molecular pathways that the occurrence of PDE may open up.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	29 Jan 2026 10:18
Last Modified:	29 Jan 2026 10:18
URI:	https://ueaeprints.uea.ac.uk/id/eprint/101785
DOI:

Actions (login required)

View Item