Ancient origins of photosynthesis: Revealing the mysteries

Evolutionary ‘molecular clock’ experiment to reveal origins of photosynthesis.

The evolution of photosynthesis refers to the subsequent evolution and origin of photosynthesis, a process used by plants to convert light energy into chemical energy. There have been many efforts made to understand just how and when it evolved.

There are two types of photosynthesis: oxygenic and anoxygenic, or oxygen-producing and non-oxygen-producing. To understand the origin of photosynthesis, scientists must make the distinction between these two types of photosynthesis.

Revealing which type of photosynthesis came first is quite challenging. It relies on knowing how fast evolution has taken place in these organisms.

Both processes are ancient, maybe up to two billion years. With the advancement in technology, the uncertainty of the origin of photosynthesis has grown even further as scientists discovered new fossils.

A landmark study at Imperial College London aims to unravel the mysteries surrounding the ancient origins of photosynthesis.

Scientists are attempting to use long-term multigenerational cultures of cyanobacteria to reveal the origin of photosynthesis. For the study, they will grow their cyanobacteria to determine the speed of their evolution.

Dr. Tanai Cardona, from the Department of Life Sciences and the leader of the Molecular Evolution Lab at Imperial, said, “This is how we gain a more conclusive understanding of the origins of photosynthesis using experimentally validated data.”

The primary focus of the experiment is to understand the ‘molecular clock’ of different types of cyanobacteria strategically located in their tree of life. This involves allowing generations of cyanobacteria to grow and evolve over a long period. Scientists will then use advanced genome sequencing techniques to track the genome changes at regular intervals.

The analysis and comparison of the genomes of these bacterial strains will help scientists determine how fast the different types of cyanobacteria evolve. It will also help them understand the sequence in which traits arise, such as components cells use to perform the different steps of photosynthesis.

Along with that, scientists will measure the rate of genome change. Doing so would allow them to determine the differences in evolutionary change in different strains or species of cyanobacteria.

Dr. Cardona said“Different groups of cyanobacteria have emerged at different points in time over billions of years, and some may have more similarities to their primordial ancestors. It is never accurate to consider any extant species as more ‘primitive’ than another, as all species arose from the same ancestor. However, some of these cyanobacteria species retain traits that are considered quite ancient, and that can shed light on how these evolved in the first place.”

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