CREDIT: ELECTRON MICROGRAPHS BY TOM DEERINCK AND MARK ELLISMAN OF NATIONAL CENTER FOR MICROSCOPY AND IMAGING RESEARCH AT THE UNIVERSITY OF CALIFORNIA AT SAN DIEGO
Seen above, Syn 1.0 was the first organism to be created with a synthetic genome back in 2010 by the Venter Institute. The recently created Syn 3.0 has over 400 fewer genes than its predecessor.

For my final entry in Scientific Adventures we'll be taking a look at the origins of ancient bacterial photosynthesis, as well the smallest synthetic organisms ever made.

The origins of photosynthesis explored

A Colombian researcher in England has been able to determine a timeline for the beginnings of bacterial photosynthesis, the process by which energy is created through sunlight and elements from the environment.

The paper looked at a specific enzyme called BchF, only found in bacteria that can synthesize bacteriochlorophyll a, one of eight types of pigments, which some bacteria can harness for photosynthesis.

Enzymes are special proteins, acting as catalysts for reactions happening to the cell.

Photosynthesis uses light photons to begin an electrochemical process, using carbon dioxide and water as fuel, to produce energy and oxygen. Some bacteria do not produce oxygen as a by-product though being separated into groups called bacteriochlorophylls by the wavelength of light they use to produce energy.

The paper used data gathered from RefSeq, an online library for genes and proteins, using BchF as a key to sift through the complete genomes from several phyla of bacteria that used chlorophyll a as their photosynthetic pigment.

Genes are long strands of DNA, a double helix structure that's made up of specific chemicals called base pairs, which code into proteins and amino acids inside the cell, tiny building blocks and machines that help the cell function in everyday life.

Scientists are able to create a general timeline of when and how bacterial evolution occurred by studying both living creatures and the fossil record, while using physical characteristics as well as complete genomic sequencing, which is much more accurate and an increasingly common option today due to its relatively low cost to run to determine a family tree of genes.

Scientists have been able to match gene sequences to when they appeared in the evolutionary timescale, effectively creating a timescale of which species transferred or caused mutations to specific genes, and when they occurred over the history of life on Earth.

By showing that the BchF enzyme is used exclusively to produce bacteriochlorophyll a, and is only found in bacteria that use the bacteriochlorophyll a pigment for photosynthesis, the researcher strongly suggested that this was the first form of photosynthesis to occur all of life on Earth.

The study also revealed that there were two different forms of BchF, and that the older version has limited to a single phyla, a type of green sulphur bacteria named Chlorobi.

While Chlorobi might have the earliest signs of BchF, it isn't the earliest case of photosynthesis, as BchF was found to be an evolutionary split, meaning that some other species had to have the rudimentary ability to perform this task as well.

The article also found out that while Chlorobi shared a possible photosynthetic ancestor with non-photosynthetic bacteria, this lack of photosynthetic food production was a trait obtained at a later point.

Due to this information the paper concluded that non-oxygen producing photosynthesis was most likely an early trait of nearly all bacteria, but that the information discovered currently led to more evolutionary questions than answers on the origins of photosynthesis in bacteria.

The article was also the first time a comprehensive look into the genetic history of non-oxygen producing photosynthesis.

Synthesized bacterium has fewest genes of any

Californian researchers have synthesized an organism with the smallest number of genes currently known to keep a creature alive, naming it Syn 3.0.

According to the study, the Mycoplasma mycoides bacterium was stripped of almost half its original 901 genes, with the researchers only needing 473 total genes to get the synthetic organism living, while giving it a genome “smaller than that of any autonomously replicating cell found in nature”. The genetic matter was transferred into an empty Mycoplasma capricolum cell, allowing the genome to have a similar environment for a positive outcome.

To put that in perspective, humans hold over 22,000 genes in their DNA, though the record holder is the freshwater flea Daphnia pulex, at over 23,000 genes.

The successful results built on both a 1999 paper where the team was able to determine that M. genitalium, which has the smallest natural genome, had redundant non-functioning genes, and a 2010 paper in which they were able to artificially replicate the complete genome of M. mycoides, placing it within the cell membrane of a similar species.

By synthesizing their DNA fragments, the team was able to create an entire artificial genome. Science News reported this process of building the genomes base components was different from how other teams have tried to achieve similar results, who instead began with stripping away unnecessary genes.

But while not all of these genes inside Syn 3.0 are what the researchers would have initially considered necessary, they certainly aren't junk either.

When the researchers tried to create a genome without inserting the genes they didn't understand the function of, the initial tests all ended in failure.

It wasn't until the 149 genes were added back into the genome, that the team found out 70 of the genes worked in conjunction with the ones whose function was already known, but in ways still not fully understood.

That still leaves 79 genes needing to be studied to fully comprehend their function in creating a living genome.

The paper also noted that while more genes could probably be removed, it would begin to the affect the growth rate, leading to a nonviable laboratory model.

If you're looking to learn about more scientific adventures, go to sciencenews.org or sciencedaily. com, and have a great summer Fanshawe.