HOTSPOT: Engineering Gene Exchange in Plants

Project title

HOTSPOT: Engineering Gene Exchange in Plants

Description

Project Description

In sexually reproducing organisms, parental chromosomes exchange segments during meiosis, a specialised cell division that produces eggs and sperm. This chromosome exchange, called crossover, reshuffles genes to create new trait combinations – the raw material for evolution and selective breeding. However, not all genes are equally amenable to reshuffling, because crossovers are uneven along chromosomes and occur in short intervals known as ‘hotspots’. Genes located in crossover-poor regions are more likely to be inherited together, while genes separated by crossover hotspots are more likely to be inherited separately. Hotspots distribution, therefore, underpins the diversity of life. 
In humans, apes and mice, hotspots are specified by a protein, called PRDM9, which binds chromosomal DNA and directs where crossovers occur. However, in many eukaryotes lacking PRDM9, including plants, yeasts, and birds, the mechanisms governing recombination positioning remain unknown. In this project, I hypothesise that in organisms lacking PRDM9, hotspots are determined by local DNA features. I will test this hypothesis in plants using a pioneering technology that allows inserting known hotspots into new defined chromosomal locations, followed by crossover quantification. By testing whether DNA determines crossover hotspot positioning, this project will provide insight into how plant genomes organise genetic exchange. Mechanistic conservation of crossover control ensures that this project’s outputs will inform how hotspots are determined in diverse eukaryotes beyond plants. The project’s outputs will enable future engineering of genetic exchange in natural and synthetic crop chromosomes resulting in controlled exchange and inheritance of agronomically important traits.