(Image via wikipedia.org)

Staff Writer: Maya Arruda

Email: marruda7@umassd.edu

Moss isn’t normally something people think about. Yeah, it’s there; it’s various shades of green and looks cool on rocks, but moss doesn’t really inspire interest in most people. 

However, last month, moss stole center stage in the science world. 

Scientists have successfully crafted a partially synthetic chromosome and integrated it into the moss genome, with the artificial chromosome not notably impacting the moss despite differences between the artificial and normal chromosome regions. 

The paper, A Designer Synthetic Chromosome Fragment Functions in Moss, was published by Nature, a creme-de-la-creme big name science journal, on January 26th, 2024.  

So, synthetic chromosomes. Who cares? 

Synthetic chromosomes are already widely used industrially and in research today, going back years before the moss squad dropped their mossy bombshell. Scientists already know how to synthesize custom DNA sequences using dNTP nucleotides (nucleic acid building blocks) and various polymerase enzymes. You can buy custom-made oligos (short DNA sequences) commercially and have them shipped to your house if you are so inclined. 

We’ve also been putting these artificial DNA sequences in other organisms for a long, long time. Special bacteria that are competent can uptake DNA from their environment through a process called transformation, which was discovered in 1928 by Freddie Griffith when he was researching pneumonia. Bacteria can be naturally competent or induced competent through chemical treatment or electroporation, basically by disrupting the bacterial cell wall/membrane so DNA can come in.  

Typically, in the lab, we make small DNA molecules called plasmids with whatever gene or sequence we want inside. In addition to the target gene, you usually add an origin of replication, sequences to control gene transcription, and an indicator gene like an antibiotic resistance gene to see which bacteria successfully took up the plasmid. Then the bacteria start expressing whatever gene it is like it’s supposed to be there, whether the gene is a human hormone, a pharmaceutical drug, or something else entirely. 

We have been doing the same thing with yeasts and other unicellular fungi since the 80s. Yeast even has their own plasmids similar to bacteria, so we use the same general approach when inserting and expressing genes for bacterial plasmas. 

In short, synthetic chromosomes are not a big deal in the field. Been there, done that, got the T-shirt. Putting synthetic chromosomes in moss is the crucial part of the research.

So why is the moss important? 

Remember when I was going on about how we already use synthetic DNA sequences? Did you notice what organisms we use: bacteria and yeast? Both are comparatively simple single-celled organisms that normally have mechanisms for incorporating foreign DNA.

Moss does not do that. Moss is a complicated multicellular organism with different cell and tissue types that do not uptake and incorporate foreign DNA. But yet, they managed to do it, and the moss lived. 

But moss will not be the final step of this research because again, it’s moss. 

Most likely, more research will focus on making synthetic chromosomes and implanting them into living beings like agricultural plants or short-lived rodents because there is greater industrial and research interest in those creatures, respectively, because they’re not moss. 

I think agricultural plants will be the most successful and prioritized direction of this synthetic chromosome implementation research. 

Food shortage is a current global issue that could be addressed by genetically modifying plants to increase yield. Moreover, genetic modification can be used to reduce harmful pesticides, another area of research with high interest. There will definitely be a wide variety of research in this area in the next few years, especially on cash crops.

I can definitely see work in mouse models with these synthetic chromosomes for research in hopes of some medical application in humans. However, that may take decades of development if IACUC or its international counterparts even let it off the ground. 

We all in the field remember the Dr. He fiasco, and I don’t think anyone will be willing to risk a repeat. 

Consequently, mammalian experiments with synthetic chromosomes won’t be as widespread as plant research, for better or for worse. 

This paper marks a cornerstone in molecular biology and paves the way for DNA manipulation of larger eukaryotic organisms like plants and animals. 

Who knows? Maybe this partially synthetic moss will make its way into textbooks alongside yeast and bacteria as a titan of molecular science.