Population genomic analyses of RAD sequences resolves the phylogenetic relationship of the lichen-forming fungal species Usnea antarctica and Usnea aurantiacoatra

By

Grewe, Felix
Lagostina, Elisa
Wu, Huini
Printzen, Christian
Lumbsch, Thorsten

Type

Article

Date of Publication

2018

Original Publication

MycoKeys

Volume

43

Pages

91-113

Subjects

Antarctica , Ascomycota , Lichens , Parmeliaceae , Phylogeny , RADseq

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers 2011-

Identifiers

DOI: https://doi.org/10.3897/mycokeys.43.29093

 

Abstract

Neuropogonoid species in the lichen-forming fungal genusUsneaexhibit great morphological variation that can be misleading for delimitation of species. We specifically focused on the species delimitation of two closely-related, predominantly Antarctic species differing in the reproductive mode and representing a so-called species pair: the asexualU.antarcticaand the sexualU.aurantiacoatra. Previous studies have revealed contradicting results. While multi-locus studies based on DNA sequence data provided evidence that these two taxa might be conspecific, microsatellite data suggested they represent distinct lineages. By using RADseq, we generated thousands of homologous markers to build a robust phylogeny of the two species. Furthermore, we successfully implemented these data in fine-scale population genomic analyses such as DAPC and fineRADstructure. BothUsneaspecies are readily delimited in phylogenetic inferences and, therefore, the hypothesis that both species are conspecific was rejected. Population genomic analyses also strongly confirmed separated genomes and, additionally, showed different levels of co-ancestry and substructure within each species. Lower co-ancestry in the asexualU.antarcticathan in the sexualU.aurantiacoatramay be derived from a wider distributional range of the former species. Our results demonstrate the utility of this RADseq method in tracing population dynamics of lichens in future analyses.