Ancestral polymorphisms shape the adaptive radiation of <i>Metrosideros</i> across the Hawaiian Islands
Jae Young Choi, Xiaoguang Dai, Ornob Alam, Julie Peng, Priyesh Rughani, Scott E. Hickey, Eoghan Harrington, Sissel Juul, Julien F. Ayroles, Michael D. Purugganan, Elizabeth A. Stacy
Abstract
Significance Some of the most spectacular adaptive radiations of plants and animals occur on remote oceanic islands, yet such radiations are preceded by founding events that severely limit genetic variation. How genetically depauperate founder populations give rise to the spectacular phenotypic and ecological diversity characteristic of island adaptive radiations is not known. We generated genomic resources for Hawaiian Metrosideros ––a hyper-variable adaptive radiation of woody taxa—for insights into the paradox of remote island radiations. We posit that divergent selection and differential sorting of an unexpectedly rich pool of ancestral variation drove the diversification of lineages. Recurring use of ancient variants from a richer-than-expected gene pool may explain how lineages can diversify to fill countless niches on remote islands.