Background: Molecular phylogenetic algorithms frequently disagree with the approaches considering
reproductive compatibility and morphological criteria for species delimitation. The question stems if
the resulting species boundaries from molecular, reproductive and/or morphological data are
definitively not reconcilable; or if the existing phylogenetic methods are not sensitive enough to agree
morphological and genetic variation in species delimitation.
Objectives : We propose to DISTATIS as
an integrative framework to combine alignment-based (AB) and alignment-free (AF) distance
matrices from ITS2 sequences/structures to shed light whether Gelasinospora and Neurospora are
sister but independent genera?
Methodology: We aimed at addressing this standing issue by
harmonizing genus-specific classification based on their ascospore morphology and ITS2 molecular
data. To validate our proposal, three phylogenetic approaches: i) traditional alignment-based, ii)
alignment-free and iii) novel distance integrative (DI)-based were comparatively evaluated on a set of
Gelasinospora and Neurospora species. All considered species have been extensively characterized at
both the morphological and reproductive levels and there are known incongruences between their
ascospore morphology and molecular data that hampers genus-specific delimitation.
Traditional AB phylogenetic analyses fail at resolving the Gelasinospora and Neurospora genera into
independent monophyletic clades following ascospore morphology criteria. In contrast, AF and DI
approaches produced phylogenetic trees that could properly delimit the expected monophyletic clades.
Conclusions : The DI approach outperformed the AF one in the sense that it could also divide the
Neurospora species according to their reproduction mode.