Deep sampling of Hawaiian Caenorhabditis elegans reveals high genetic diversity and admixture with global populations

Abstract

Hawaiian isolates of the nematode species Caenorhabditis elegans have long been known to harbor genetic diversity greater than the rest of the worldwide population, but this observation was supported by only a small number of wild strains. To better characterize the niche and genetic diversity of Hawaiian C. elegans and other Caenorhabditis species, we sampled different substrates and niches across the Hawaiian islands. We identified hundreds of new Caenorhabditis strains from known species and a new species, Caenorhabditis oiwi. Hawaiian C. elegans are found in cooler climates at high elevations but are not associated with any specific substrate, as compared to other Caenorhabditis species. Surprisingly, admixture analysis revealed evidence of shared ancestry between some Hawaiian and non-Hawaiian C. elegans strains. We suggest that the deep diversity we observed in Hawaii might represent patterns of ancestral genetic diversity in the C. elegans species before human influence.

Natural variation in a glucuronosyltransferase modulates propionate sensitivity in a C. elegans propionic acidemia model

“…The nematode Caenorhabditis elegans is a bacterivore found around the world [8][9][10]. In the laboratory, C. elegans can be fed different species and strains of bacteria [11,12], but the vast majority of studies use the Escherichia coli strain OP50.…”

Natural variation in a glucuronosyltransferase modulates propionate sensitivity in aC. eleganspropionic acidemia model

“…More than 330 wild C. elegans strains are currently available in CeNDR [31], 42 of these strains contain the Gly16* variant in glct-3 . The majority of strains that contain the Gly16* variant (33/42) were isolated on the Hawaiian islands ( Figure S5 ), which are known to harbor the most genetically divergent C. elegans individuals [10]. An additional three strains also have variants that are predicted to cause a loss of glct-3 function (ECA733, JU1395, and ECA723).…”

“…The nematode Caenorhabditis elegans is a bacterivore found around the world [8–10]. In the laboratory, C. elegans can be fed different species and strains of bacteria [11, 12], but the vast majority of studies use the Escherichia coli strain OP50.…”

“…The vast majority of C. elegans studies rely on the laboratory-adapted strain named N2, from Bristol, England [17]. Over the last twenty years, hundreds of C. elegans strains have been collected worldwide from natural habitats [10, 18–23]. C. elegans is a self-fertilizing hermaphrodite and, therefore, different wild strains can be easily maintained as fully isogenic strains.…”

Evolution and Developmental System Drift in the Endoderm Gene Regulatory Network of Caenorhabditis and Other Nematodes

“…These latter studies have been facilitated through quantitative genetics approaches, by availing of over 300 wild isolates obtained from different continents over the past decade, whose genomes have been fully sequenced (Andersen et al, 2012;Cook et al, 2016Cook et al, , 2017Zhao et al, 2018). A recent sampling effort in Hawaii further identified C. elegans strains that show large amount of genetic diversity (Crombie et al, 2019). These rich resources offer a unique and attractive opportunity for both intra-and interspecies comparative studies.…”