Into the wild: exploring natural modifiers of meiotic recombination in Solanum pimpinellifolium

Supervision: The project will be supervised by Charles J. Underwood at the Max Planck Institute for Plant Breeding Research.

Abstract: Meiosis is a specialized cell division that lies at the centre of hereditary. During Meiosis homologous chromosomes pair and reciprocal exchanges of genetic material – crossovers – occur. The absolute number of crossovers per pair of homologous chromosomes is tightly controlled. In most species at least one crossover per chromosome pair (the so-called “obligate crossover”) is absolutely required for normal segregation, and crossovers are usually limited to less than three crossovers per chromosome pair. Despite this, variation in crossover rate is observed within and between species. The focus of this PhD project will be to identify genetic loci that control crossover number in natural accessions of the tomato wild relative, Solanum pimpinellifolium

Genetic loci, and underlying genes, that control meiotic crossover rate have been identified in several animal species including humans, cattle and sheep. In the model flowering plant Arabidopsis thaliana, several loci have also been cloned, including the HEI10 gene. However, natural modifiers of recombination rate have not been cloned in other dicot species. In this project eight different Solanum pimpinellifolium accessions, that represent the phylogenetic and geographical diversity of the whole species, will be used to identify natural modifiers of crossover rate. Intercross populations have been developed for use in this project and the appointed PhD student would genotype recombinant populations by sequencing, perform QTL analysis, identify loci that associate with crossover rate, and ultimately clone causal genes.

Key publication: Ziolkowski, P. A., Underwood, C. J., Lambing, C., Martinez-Garcia, M., Lawrence, E. J., Ziolkowska, L., ... & Henderson, I. R. (2017). Natural variation and dosage of the HEI10 meiotic E3 ligase control Arabidopsis crossover recombination. Genes & development, 31(3), 306-317.

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