Clonal Expansion in Ageing

The first talk of our new WCMR ‘Research in Progress’ seminar series for 2019-20 was given by Dr Brendan Payne. In his talk, Dr Payne described a new model which allows the process of clonal expansion to be tracked in ageing. Read on to find out more.

Mitochondria play an important role in the ageing process. Mitochondria contain their own DNA (the genetic code). As we get older, this mitochondrial DNA becomes damaged. The damage is known as mutations. Over time, these mutations rise to very high levels in some cells. The cells that have high levels of mutation can no longer function properly, which is part of the reason why our organs work less well as we age.

The process by which some cells reach very high levels of mutation is known as ‘clonal expansion’. This is illustrated in the diagram below. The cell at the top contains many copies of healthy mitochondrial DNA, which are shown as the small green circles within the mitochondrion. If a single copy of the mitochondrial DNA becomes damaged, shown as the small red circle within the mitochondrion in the middle cell, this mutation can undergo ‘clonal expansion’. This can lead to a cell that contains many copies of mitochondrial DNA with the mutation, shown as the red circles within the mitochondrion in the bottom cell.

Clonal expansion is not very well understood by scientists and has been difficult to study in the laboratory. The new model we have created will help us to better understand the role that mitochondrial damage plays in human ageing and in inherited mitochondrial diseases. This model will also allow us to study whether clonal expansion might be a target for drug treatments.

To read more about Dr Payne’s research projects within the WCMR, click here.