12/12/2025
🚨New Science Paper🚨 Since the dawn of the genomic era, researchers have sequenced tiny bits of DNA and mapped them onto a single, painstakingly assembled reference genome. The catch is that anything missing from that reference disappears from view. But we now know that every individual—bird or human—carries its own “accessory genome”: deletions, inversions, or sometimes whole genes, found only in some individuals. The full collection of this genomic diversity is the pangenome, with each organism sampling a different slice of the species-wide DNA pool
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In our new Science paper (link in comments), we explore this “DNA dark matter” in scrub-jays, a group dear to the Moore Lab. Led by the Edwards Lab at Harvard, the work shows that bird genomes can change fast. The Channel Island Scrub-Jay, for instance, has a genome about 6% smaller than its relatives, shaped by the accumulation of mildly harmful mutations in its tiny island population. Meanwhile, Woodhouse’s Scrub-Jays carry accessory DNA that seems mostly beneficial—except for a Z chromosome riddled with a giant selfish element that repeats in 18,000-base chunks, the largest repetitive unit ever found in birds. Authors include Moore Lab Director and Oxy alum ’17, who began his scrub-jay research as an undergraduate and is now studying Island Scrub-Jay genome evolution as a postdoc at UCLA.
