What drives speciation? Examination into the evolutionary events of more than 100 Aspergillus species

J.L. Nyboa, T.C. Vestha, S. Theobalda, I. Kjaerboellinga, J.C. Frisvada, T.O. Larsena, R. Riley b, A. Salamovb, I.V. Grigorievb, S.E. Bakerc and M.R. Andersena

Author address: 

aBiotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, DK bJoint Genome Institute, Walnut Creek, CA, USA cJoint Bioenergy Institute, Berkeley, CA, USA


The study of speciation - how new species arise, diverge and remain separate, has a central role in evolutionary biology. Partly because it embraces so many disciplines, including population genetics, behavioral sciences, comparative genomics, evolutionary biology, biodiversity, biogeography and ecology. It also remains one of the most fascinating questions in evolution. Speciation is nearly impossible to study and in most cases, we know very little about the genetic basis of species formation. But in this project we aim to identify evolutionary events that can drive speciation, such as gene duplications, creations and losses, and horizontal gene transfers between closely or distantly related species within the genus of the filamentous fungi Aspergillus. This diverse genus holds species relevant to both plant and human pathology, food biotechnology, enzyme and bulk chemical production, model organisms, and it even contains some extremophiles. To identify these events, we have developed a homologous protein prediction software that has been used to generate a high-resolution pan-genomic map. From where, we have identified genes specific to species, clades and core that allows for guilt-by-association-based mapping of genotype-to-phenotype. Our results illustrate a highly diverse genus where 500-2000 genes are unique to each species. These genes are predominantly within regulation or compound biosynthesis, supporting the notion of natural selection. A conservative estimate of the number of protein families shared by all Aspergillus species is surprisingly low, only about 2600 core families, suggesting high environmental adaptation within this genus.


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Full conference title: 

The Fourteenth International Aspergillus Meeting, Asilomar Conference Center, Pacific Grove, CA, USA
    • Asperfest 14 (2017)