Ramesh Arunkumar, Ph.D. student

Department of Ecology and Evolutionary Biology
University of Toronto
25 Willcocks Street
Toronto, Ontario, Canada
M5S 3B2

Office: Earth Science Building 2043, 416-978-8324
Email: ram.arunkumar@utoronto.ca

 Degrees

  B. Sc. (Honours)   (2011) Ecology and Evolutionary Biology, University of Toronto, Canada.

 Current Position

 Ph.D. student

Ph.D. student, Professor Barrett's lab, Department of Ecology and Evolutionary Biology, University of Toronto. Co-advised by Stephen I. Wright.

 RESEARCH INTETRESTS

The floral polymorphism tristyly is characterised by the differential positioning of sex organs. There are three floral morphs (long-, mid- and short-styled; L, M, S; Fig 1). I am interested in investigating the genetic, genomic and phenotypic basis for tristyly in the annual aquatic plant Eichhornia paniculata (Pontederiaceae).

Tristyly figure

Fig 1.

I. Molecular genetic basis of tristyly

The evolution of adaptive multi-locus polymorphisms has been a long-standing puzzle in molecular population genetics. A cluster of linked genes known as a supergene complex has been proposed to govern a number of traits such as colour and pattern polymorphism in insects and molluscs. Although tristyly is one of the oldest cases for which a supergene complex has been proposed, there has been little supporting molecular genetic evidence. I am interested in identifying the genomic regions governing tristyly and uncovering the mechanisms by which the proposed supergenes can be maintained.

II. Genetic and genomic consequences of the breakdown of tristyly

The breakdown of tristyly leads to male and female sex organs reaching the same height within a flower. This breakdown has contributed to the origin of selfing E. paniculata variants via two alternative pathways (below). I am interested in investigating the genetic architecture and the population genomic consequences of the breakdown of tristyly. Understanding the genetics and genomics of this transition to selfing will contribute towards our understanding of the genetics of reproductive adaptation.

Breakdown of tristyly

 

 

 Publications

 

Arunkumar R, Josephs EB, Williamson RJ, & Wright SI. (2013). Pollen-specific, but not sperm-specific, genes show stronger purifying selection and higher rates of positive selection than sporophytic genes in Capsella grandiflora. Molecular Biology and Evolution 30: 2475-2486. doi: 10.1093/molbev/mst149

Barrett SCH, Arunkumar R, & Wright SI. The demography and population genomics of evolutionary transitions to self-fertilization in plants. Philosophical Transactions of the Royal Society of London Ser. B. In press.