Our research focuses on plant genome evolution, ranging from the evolution of plant chromosome numbers and incidence of polyploidy, to detailed analyses of the composition of plant chromosomes and genomes. Of special interest are analyses of the dynamics of genomic changes following hybridization and polyploidization. Our research includes aspects of phylogeny and systematics, as well as genomics and genetics. We focus explicitly, but not exclusively, on the evolution of the repetitive DNA fraction of the genome which encompasses dispersed transposable elements and various tandem repeats such as telomeric motifs, rDNAs and satellite DNAs.

Chromosome number and structure dynamics are important to speciation and evolution. Application of high-throughput sequencing technologies in concert with fluorescence in situ hybridization allows us to study chromosome evolution in systems with highly dynamic chromosome numbers. Of special interest are supernumerary B chromosomes (Bs) and supernumerary chromosomal segments (SCSs).

Polyploidy is particularly important in plant evolution. We focus on identifying parental origin of polyploids and use a comparative approach to study genome evolution following auto- and allopolyploidization. We also develop novel approaches to infer the age of allopolyploids, which are used for calibrating the dynamics of the evolution of their repetitive DNA fraction.

Repetitive DNA represents the most dynamic fraction of plant genomes. Both dispersed transposable elements and tandemly repeated satellite DNAs are important drivers of genome size and chromosome structure evolution in plants. Their dynamic evolution is correlated with high levels of divergence even among among closely related taxa. We utilize high-throughput sequencing and graph-based clustering approaches, in addition to experimental approaches, for characterization and inferring the patterns of the evolution of repetitive elements in various plant genomes.

Recent Publications

rDNA Loci Evolution in the Genus Glechoma (Lamiaceae). Tae-Soo Jang, Jamie McCann, John S. Parker, Koji Takayama, Suk-Pyo Hong, Gerald M. Schneeweiss, Hanna Weiss-Schneeweiss. November 2016. PLoS One.

The impact of reconstruction methods, phylogenetic uncertainty and branch lengths on inference of chromosome number evolution in American daisies (Melampodium, Asteraceae). Jamie McCann, Gerald M. Schneeweiss, Tod F. Stuessy, José L. Villaseñor, Hanna Weiss-Schneeweiss. September 2016. PLoS One.

Molecular and cytogenetic evidence for an allotetraploid origin of Chenopodium quinoa and C. berlandieri (Amaranthaceae). Bozena Kolano, Jamie McCann, Maja Orzechowska, Dorota Siwinska, Eva M. Temsch, Hanna Weiss-Schneeweiss. July 2016. Molecular Phlyogenetics and Evolution.

Structural polymorphisms and distinct genomic composition suggest recurrent origin and ongoing evolution of B chromosomes in the Prospero autumnale complex (Hyacinthaceae). Tae-Soo Jang, John S. Parker and Hanna Weiss-Schneeweiss. January 2016. New Phytologist.

 

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