Dodsworth Lab
  Evolutionary & Molecular Botany

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Current Projects - **Prospective PhD/MSc opportunities in the following areas**

1. Phylogenomics of the angiosperms (flowering plants): overview and selected clades
Utilising advances in high-throughput sequencing this project aims to produce a complete generic level phylogenomic tree of angiosperms, using a custom set of 353 nuclear genes. Aside from systematic implications these new phylogenomic frameworks will be used for studies of character evolution, community phylogenetics, niche diversification and so on. This is part of the Plant and Fungal Trees of Life (PAFTOL) project, one of Kew’s strategic outputs. Sub-projects are focussing on the generic-level relationships in Solanaceae and selected monocot families. 

2. Diversification of Nicotiana section Suaveolentes (Solanaceae)  
Nicotiana sect. Suaveolentes consists of approximately 35 species of allotetraploid origin, with most species recently radiating in Australia within the last 2-3 million years. Diploid species of Nicotiana are n = 12, and allotetraploid species are n = 24. In Nicotiana sect. Suaveolentes polyploid species range from n = 24 down to n = 15, a dysploid series resulting from complex chromosome reduction processes associated with diploidisation.  A new phylogenomic framework for the section paints section Suaveolentes as a recent and rapid radiation, owing to the timing of most speciation events in the last ~2 million years and the occurrence of rampant incomplete lineage sorting, particularly in plastid haplotypes (Dodsworth et alin prep.)

3. Evolution of repetitive DNA and genome dynamics in angiosperms 
Studies in several groups of angiosperms have shown that there is a phylogenetic signal in the abundance of different types of repetitive DNA and that patterns of repeat accumulation/degradation in angiosperm genomes reflect similar processes in related species (Dodsworth et al. 2015 - Syst. Biol.; Dodsworth et al. 2016 - Bio. J. Linn. Soc.).  Traditionally such repetitive DNA has been discarded by researchers as ‘junk’, but it has a useful phylogenetic signal that is perhaps characteristic of other parts of the nuclear genome (e.g. rDNA).  I am building on these studies by investigating broader patterns of repeat dynamics in other angiosperm groups and by developing a Bayesian framework to implement a model that more accurately encapsulates the evolution of repetitive elements in genomes.  This will further our understanding of the non-coding part of the genome in plants, and one particular area of interest is genome evolution post-polyploidization.  Given that most of our crop species are polyploids of various ages, this will be important in the future development of crop species in the context of food security and climate change.

4. Molecular mechanisms underpinning floral diversity in monocots  
Petaloid monocots include some of the most important horticultural species from different families (e.g. tulips from Liliaceae; daffodils from Amaryllidaceae; orchids from Orchidaceae). Many of these species have in common two whorls of petaloid (petal-like) organs in the first two whorls of the flower (the perianth), compared to sepals + petals of most eudicot species. However, monocots are diverse, and many include novel organs (e.g. the corona of daffodils or the nectar spurs of many orchids). Understanding the genetic basis for these noval organ types is important to understand how they have evolved and also the context of past and future cultivar development in species with horticultural promise.