Clever Control of Crossovers

I am Divyanshu Sahu, a second year PhD student in Raphael Mercier’s group at the Chromosome Biology Department, at MPIPZ.

I am currently working on a project which aims to increase crossovers in the centromere proximal regions of plants. Crossovers are a hallmark of meiosis. They are very important for plants and animals, since it ensures proper segregation of the chromosomes and increased genetic diversity. Imagine, your mother has blue eyes and blonde hair while your father has black hair and brown eyes. But you have a combination of blue eyes and black hair, which is possible because the crossovers help in generating this combination. 

Existing research shows that crossovers are heavily suppressed near the centromeres, but the region has some useful genes. For example, in wheat, we have several genes which when activated can help the plants to fight off several microbes, pests, etc. As a result of our research, we can help the plant breeders to access these genes, combine them with existing high-yielding varieties, and eventually making the crops both high-yielding and resistant to pests.

Our lab works on Arabidopsis thaliana as the model organism. It is a small plant, easy to grow, has a short lifespan, and a small genome comprising of 10 chromosomes in diploid state. In our lab we found some novel mutants which have increased the crossovers in the centromere proximal region. Therefore, in my project I am combining these mutations together to see how far can we increase the crossovers, and study the genetic interactions of these mutations. After generating the mutants, I use whole genome sequencing of the mutants to find in which regions the crossovers are taking place. I also use fluorescent seeds and microscopy to check if these mutants have increased crossovers compared to the wildtype plants. Eventually I will also generate the same mutants in tomato to evaluate their potential to increase crossovers in the centromere proximal regions of crops.

Something extremely fascinating about my project is, our current scientific knowledge and technology enables us to find these crossovers and turn these rare crossover events into frequent ones. Studying plants provides me the potential to contribute towards sustainable agriculture and ensuring global food security.