Dr Ilia J Leitch

Senior Research Leader


Trait Diversity and Function


Character Evolution


Genome size, chromosomes, polyploidy, transposable elements, nitrogen and phosphorus, flow cytometry

I lead a team of Kew scientists investigating character evolution in plants. We conduct research aimed at identifying and understanding (i) how different plant traits interact and evolve to generate the diversity of plant life, and (ii) how key characters influence, or are influenced by, global environmental change. The particular characters currently under study range across all levels of plant organization from the genomic to the whole plant level.

My own research is focused on genomic characters such as genome size, chromosome organization, and DNA repeats (see project: Uncovering the genomic diversity of plants) to (i) understand the origin, evolution and biological significance of the immense diversity of genomic characters across land plants, and (ii) determine how these characters impact at the whole plant level to influence how, when, and where plants grow and respond to global change.

I am also involved in (i) the Plant Tree of Life project, (ii) the plant component of the Darwin Tree of Life project, and (iii) lead the generation and collation of genome size data for the Plant DNA C-values database.

The Plant DNA C-values database comprises the most comprehensive compilation of genome size data for land plants and algae available on the internet. The latest release 7.1 (April 2019) contains data for over 12,000 species.

  • BSc (Hons), Univ. Bristol, 1985
  • PhD, Univ. Bristol, 1990

Guo K, Pyšek P, van Kleunen M, Kinlock NL, Lučanová M, Leitch IJ, Pierce S, Dawson W, Essl F, Kreft H, Lenzner B, Pergl J, Weigelt P, Guo W-Y. (2024)

Plant invasion and naturalization are influenced by genome size, ecology and economic use globally. 

Nature Communications 15: 1330.

Bureš P, Elliott TL, Veselý P, Šmarda P, Forest F, Leitch IJ, Nic Lughadha E, Soto Gomez M, Pironon S, Brown MJM, Šmerda J, Zedek F. (2024) 

The global distribution of angiosperm genome size is shaped by climate. 

New Phytologist 142: 744-459.

Schley RJ, Pellicer J, Ge X-J, Barrett C, Bellot S, Guignard MS, Novák P, Suda J, Fraser D, Baker WJ, Dodsworth S, Macas J, Leitch AR, Leitch IJ. (2022) 

The ecology of palm genomes: repeat-associated genome size expansion is constrained by aridity. 

New Phytologist 236: 433–446

Faizullah, L., Morton, J.A., Hersch-Green, E.I., Walczyk, A.M., Leitch, A.R. & Leitch, I.J. (2021)

Exploring environmental selection on genome size in angiosperms.

Trends in Plant Science 26: 1039-1049.

Wang, X., Morton, J., Pellicer, J., Leitch, I.J. & Leitch, A.R. (2021)

Genome downsizing after polyploidy: mechanisms, rates and selection pressures.

The Plant Journal 107: 1003-1015.

Novák, P., Guignard, M.S., Neumann, P., Kelly, L.J., Mlinarec, J., Koblížková, A., Dodsworth, S., Kovařík, A., Pellicer, J., Wang, W., Macas, J., Leitch, I.J., Leitch, A.R. (2020)

Repeat-sequence turnover shifts fundamentally in species with large genomes.

Nature Plants 6: 1325–1329.

Guignard, M.S., Crawley, M.J., Kovalenko, D., Nichols, R.A., Trimmer, M., Leitch, A.R. & Leitch, I.J. (2019).

Interactions between plant genome size, nutrients and herbivory by rabbits, molluscs and insects on a temperate grassland.

Proceedings of the Royal Society B: Biological Sciences 286: 20182619.  

Hidalgo, O., Pellicer, J., Christenhusz, M.J.M., Schneider, H., Leitch, A.R. & Leitch, I.J. (2017).

Is there an upper limit to genome size?

Trends in Plant Science 22: 567-573.

Guignard, M.S., Nichols, R.A., Knell, R.J., Macdonald, A., Romila, C-A., Trimmer, M., Leitch, I.J. & Leitch, A.R. (2016).

Genome size and ploidy influence angiosperm species' biomass under nitrogen and phosphorus limitation.

New Phytologist 210: 1195-1206. 

Dodsworth, S., Leitch, A.R. & Leitch, I.J. (2015).

Genome size diversity in angiosperms and its influence on gene space.

Current Opinion in Genetics & Development 35: 73-78. 

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Ilia J. Leitch

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Ilia J. Leitch


Ilia J. Leitch






+ 44 (0) 208 332 5329