People
Leitch, Ilia J.
| Job Title | Plant Genetics Scientist |
|---|---|
| Department | Jodrell |
| Section | Genetics |
| Science Teams |
Monocots I: General Alismatids & Lilioids Monocots II: Commelinids Large-Scale Syntheses |
| Joined Kew | 1993 |
| Foreign Language(s) | French. |
Qualifications & Appointments
BSc (Hons), Univ. Bristol, 1985
PhD, Univ. Bristol, 1990.
Role
To understand the evolutionary significance of the immense diversity of plant genomes (i.e. size, chromosome number, organization and composition).
Research into increasing knowledge of plant genome organisation and evolution focuses on three areas:
(1) Physical organization of genomes - patterns, constraints and evolution: the physical organization of DNA within chromosomes and between whole chromosomes and genomes is studied using fluorescence in situ hybridisation (FISH) including chromosome painting strategies, which enable whole genomes to be visualised in hybrid and polyploid taxa; understanding how specific DNA sequences are organised within chromosomes highlights possible evolutionary constraints on genome organisation; visualizing the organisation of different genomes in hybrids and polyploids provides insights into how genomes evolve following polyploid formation, a process estimated to occur at least once in probably all angiosperms.
(2) Plant genome size – diversity and evolution: estimating, collating (including the Plant DNA C-values database www.kew.org/genomesize/homepage.html) and analysing data has provided insights into our understanding of the evolutionary significance of the huge range (over 1700-fold) of C-values encountered in land plants (Embryophytes). Superimposing C-value data onto increasingly robust phylogenies of land plant groups allows predications to be made as to the size of ancestral genomes and to document where increases and decreases in genome size may have taken place during evolution. Analysing genome size evolution in polyploids reveals that DNA loss or genomic downsizing is a frequent response to the increased genomic DNA load of polyploidy nucleus. Tracking the exact timing and magnitude of DNA loss is currently being investigated in a range of polyploids.
(3) Composition, organisation and dynamics of genome: Understanding the mechanisms and evolutionary forces which maintain or change genome size is currently a hot topic of debate. Ongoing work focusing on Liliaceae (which includes the largest genomes so far reported in plants) aims to investigate this further by analysing the composition, organisation and dynamics of various classes of repetitive DNAs (e.g. retrotransposons and satellites) which make up the bulk of their genomes.
Projects
Genomic Studies in Angiosperms
Selected Publications 2001-2005
Leitch, I.J., Bennett, M.D. (2002). The genome: integrating genomic characters for a holistic approach to understanding plant genomes. In Baijnath, H. & Singh, Y. (eds) Rebirth of Science in Africa - a shared vision for life and environmental sciences. Pretoria: Umdaus Press. 39-50.
Leitch, I.J. & Bennett, M.D. (2002). New insights into patterns of nuclear genome size evolution in plants. Current Genomics 3: 551-562.
Bennett, M.D., Leitch, I.J., Price, H.J. & Johnston, J.S. (2003). Comparisons with Caenorhabditis (~100 Mb) and Drosophila (~175 Mb) using flow cytometry show genome size in Arabidopsis to be ~157 Mb and thus 25% larger than the Arabidopsis genome initiative estimate of ~125 Mb. Annals of Botany 91: 547-557.
Leitch, I.J., Bennett, M.D. (2004). Genome downsizing in polyploid plants. Biological Journal of the Linnean Society 82: 651-663.
Leitch, I.J., Soltis, D.E., Soltis, P.S. & Bennett, M.D. (2005). Evolution of DNA amounts across land plants (Embryophyta). Annals of Botany 95: 207-217.
Selected Publications pre-2001
Leitch, I.J. & Bennett, M.D. (1997). Polyploidy in angiosperms. Trends in Plant Science 2: 470-476.
Cox, A.V., Abdelnour, G.J., Bennett, M.D. & Leitch, I.J.. 1998. Genome size and karyotype evolution in the slipper orchids (Cypripedioideae: Orchidaceae). American Journal of Botany 85: 681-687.
Leitch, I.J., Chase, M.W. & Bennett, M.D. (1998). Phylogenetic analysis of DNA C-values provides evidence for a small ancestral genome size in flowering plants. Annals of Botany 82: 85-94.
Yang, Q., Hanson, L., Bennett, M.D. & Leitch, I.J.. (1999). Genome structure and evolution in the allohexaploid weed Avena fatua L. (Poaceae). Genome 42: 512-518.
Adams, S.P., Leitch, I.J., Bennett, M.D. & Leitch, A.R. (2000). Aloe L. - a second plant family without (TTTAGGG)