Programmed DNA elimination - the curious case of vastly different genomes among the cells of an organism

What do songbirds, lampreys, and fungus gnats have in common? They all have vastly different genomes in their germline vs. soma cells due to the phenomenon of programmed DNA elimination. At some point during embryo development, chromosome fragments or entire chromosomes are removed from somatic cells in a consistent manner, however, it remains mysterious why this phenomenon evolved in these diverse organisms. I will discuss recent 'omics' insights into programmed DNA elimination, with a particular focus on the songbird germline-restricted chromosome which is likely present in
over 5000 songbird species. Is it possible that germline/soma genome differences are much more widespread across the Tree of Life than currently appreciated?