Zebra finch testis and somatic tissue sequencing

Genomes can vary within individual organisms. Programmed DNA elimination leads to dramatic changes in genome organisation during the germline–soma differentiation of ciliates, lampreys, nematodes, and various other eukaryotes. A particularly remarkable example of tissue-specific genome differentiation is the germline-restricted chromosome (GRC) in the zebra finch which is consistently absent from somatic cells. Although the zebra finch is an important animal model system, molecular evidence from its large GRC (>150 megabases) is limited to a short intergenic region and a single mRNA. Here, we combined cytogenetic, genomic, transcriptomic, and proteomic evidence to resolve the evolutionary origin and functional significance of the GRC.