Genetic delineation between and within the widespread coccolithophore morpho‐species Emiliania huxleyi and Gephyrocapsa oceanica (Haptophyta)

• Published in: Journal of Phycology
• Main Authors: Bendif, El Mahdi, Probert, Ian, Carmichael, Margaux, Romac, Sarah, Hagino, Kyoko, de Vargas, Colomban
• Other Authors: Mock, T., EPOCA, Marie Curie Intra-European Fellowship, ASSEMBLE
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Ocean acidification
• Online Access: http://dx.doi.org/10.1111/jpy.12147; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjpy.12147; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpy.12147

E miliania huxleyi and G ephyrocapsa oceanica are abundant coccolithophore morpho‐species that play key roles in ocean carbon cycling due to their importance as both primary producers and cal‐cifiers. Global change processes such as ocean acidification impact these key calcifying species. The physiology of E . huxleyi, a developing model species, has been widely studied, but its genetic delineation from G . oceanica remains unclear due to a lack of resolution in classical genetic markers. Using nuclear (18S r DNA and 28S r DNA ), mitochondrial ( cox1, cox2, cox3, rpl16, and dam ), and plastidial (16S r DNA , rbcL , tufA, and petA ) DNA markers from 99 E . huxleyi and 44 G . oceanica strains, we conducted a multigene/multistrain survey to compare the suitability of different markers for resolving phylogenetic patterns within and between these two morpho‐species. The nuclear genes tested did not provide sufficient resolution to discriminate between the two morpho‐species that diverged only 291Kya. Typical patterns of incomplete lineage sorting were generated in phylogenetic analyses using plastidial genes. In contrast, full morpho‐species delineation was achieved with mitochondrial markers and common intra‐morpho‐species phylogenetic patterns were observed despite differing rates of DNA substitution. Mitochondrial genes are thus promising barcodes for distinguishing these coccolithophore morpho‐species, in particular in the context of environmental monitoring.