Hybrid species formation in Brassica

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New species often evolve through hybridisation, i.e. two species coming together to form a new species with genetic information from both parent species. This process is now known to be very common, particularly in the flowering plants, and is responsible for many of our agriculturally significant food crops. Examples of hybrid or many-genome (polyploid) species include wheat, potato, sugarcane, banana and canola.Hybrid plants have to deal with two competing sets of genetic information. During sexual reproduction, meiosis must be tightly controlled in order to produce stable, fertile progeny, which is a requirement for a hybrid to establish as a new species. However, controlling meiosis when two different, potentially interfering sets of chromosomes are present in one cell can be problematic. Plants naturally stabilise on their own in the wild, as hybrid species are extraordinarily common. However, human attempts to make synthetic hybrids are often unsuccessful, and our understanding of the mechanisms behind hybrid stabilisation is poor. The Brassica genus, which includes many important crops such as oilseed rape, broccoli, cabbage and mustards, provides an excellent model with which to explore hybrid species formation. For example, the species which comprises oilseed rape (B. napus) is an evolutionary hybrid between the species containing our cultivated cabbages (B. oleracea) and the species containing cultivated turnip (B. rapa).By investigating how hybrid species form, I hope to work out how to utilise these natural evolutionary processes for human agricultural benefit in the Brassica genus. Hybridisation and genome doubling are processes which often result in increased vigour and ability to exploit different environmental niches in nature. Hence, if we can harness these processes to produce new hybrid species, such species may have a wider tolerance of environmental conditions such as heat, drought and disease, sustaining agricultural production.