Experimental evolution of Fusarium oxysporum reveals genome rearrangements as the major driving force governing short-term evolution
29th Fungal Genetics Conference, California, Amerika Birleşik Devletleri, 13 - 18 Mart 2017, (Yayınlanmadı)
- Yayın Türü: Bildiri / Yayınlanmadı
- Basıldığı Şehir: California
- Basıldığı Ülke: Amerika Birleşik Devletleri
- Acıbadem Mehmet Ali Aydınlar Üniversitesi Adresli: Hayır
Özet
Natural selection is a fundamental evolutionary process that acts on changes in a genome and results in the adaptation of an organism. The most common forms of genome changes range from single nucleotide polymorphism (SNPs), small insertion/deletion, segmental duplication, chromosomal rearrangement, to whole genome duplication. How do these different changes influence the evolutionary processes under different selection pressure? To explore answers to these questions, this study takes an experimental approach to observe evolving processes using a model organism Fusarium oxysporum, a highly adaptive species complex containing the mobile and lineage-specific (LS) chromosomes that are rich for transposons and determines host-specific pathogenicity. The same starting population (F. oxysporum f. sp. lycopersici strain 4287, a tomato pathogenic isolate) was passaged ten times through two distinct serial transfers in its host or on rich media plates. We have sequenced 5 evolved populations from each serial transfer at the end of the experiment. Comparative genomics revealed the presence of segmental duplications and deletions on parts of LS regions, suggesting that genome rearrangements are the major forces that shape short-term evolution. Retaining a relatively constant mutation rate, there is a much lower possibility to accumulate beneficial SNPs in short time frame. As expected, we observed few SNPs among these evolving populations. Interestingly, the populations that evolved in rich media tended to lose parts of or entire LS chromosomes, suggesting the dispensable nature and energy cost associated with these chromosomes when growing on a petri dish. These results highlight that different evolutionary constraints determine the outcome when populations are adapting to different environments