GermlineChrom

Evolution and development of germline–soma genome differences of birds

In some organisms, the genomes of germline and somatic cells differ substantially. Programmed DNA elimination is considered to be responsible for this observation as it removes genes and repetitive elements during somatic cell differentiation. The EU-funded GermlineChrom project will focus on the germline-restricted chromosome encountered in the germline of certain bird species, such as the zebra finch, and believed to contain genetic material dispensable or detrimental for somatic cells. Researchers will study and provide fundamental insight into the role of programmed DNA elimination, how it has evolved and its inheritance mechanism in the zebra finch. 

Combining multi-omics with developmental and functional genomics

The aim of GermlineChrom is to test whether programmed DNA elimination allows germline-specific expression of developmental genes to minimize germline–soma conflict. Using the germline-restricted chromosome (GRC) of the zebra finch as a unique study system, we have recently pioneered high-throughput genomics to overcome previous limitations. Combining our novel approach with transcriptomics, proteomics, cytogenetics, and developmental and functional genomics will provide unprecedented insights into the evolution and function of germline–soma genome differences.

An evolutionary framework for programmed DNA elimination

First, GermlineChrom will establish the so far first GRC study system by generating a zebra finch GRC reference assembly. Second, GermlineChrom will test how the GRC is inherited and maintained in zebra finch populations. Third, GermlineChrom will elucidate the long-term evolutionary history of GRCs across songbirds to reveal genes that are most conserved and thus candidates for GRC function. Fourth, GermlineChrom will trace GRC expression and elimination across zebra finch development, and functionally validate candidate genes. Altogether, GermlineChrom will establish an evolutionary framework which will significantly advance our understanding of programmed DNA elimination during germline–soma differentiation, a phenomenon likely widespread across the Tree of Life.