The evolution of the allorecognition gene repertoire in the Podospora anserina species complex

• Across the Tree of Life, self/non-self recognition is typically achieved through highly polymorphic loci under balancing selection. In fungi, vegetative conspecific recognition, or allorecognition, is defined by the compatibility interactions between loci known as het genes. In this study we explore the evolution of the het genes in the model fungus Podospora anserina and its closest relatives (the Podospora anserina species complex). First, we used chromosome-level genome assemblies to resolve their phylogenetic relationships. We found that the species in the complex are well defined but diversified recently and rapidly, leading to high degrees of conflict at deep branches of the phylogeny. Unlike typical orthologous genes from the complex, some allorecognition genes (het-z and het-s) show trans-species polymorphism, a hallmark of long-term balancing selection. By contrast, the het genes belonging to the HNWD family exhibit a high turn-over, with losses and duplications happening often. In particular, the species P. pseudocomata has a considerable increase of HNWD genes. Unexpectedly, we show that the HNWD paralogs have clean defined boundaries flanked by a target site duplication (TSD), implicating a DNA transposon-like mechanism in the genesis of new duplicates. Overall, our data highlights the diversity of evolutionary histories behind individual self/non-self recognition genes at short evolutionary timescales.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

Nyckelord

Podospora

Allorecognition

heterokaryon incompatibility

vegetative incompatibility

balancing selection

Transposable elements

NLRs

Biology with specialization in Evolutionary Genetics

Biologi med inriktning mot evolutionär genetik

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)