CRISPR-Cas9 could have the potential to combat global coral bleaching events

Extensive studies have confirmed that the Great Barrier Reef in Australia has lost over 50% of its corals. In fact, due to constantly occurring global coral bleaching events since the 1980s which trigger two of the events in 2016 and 2017 each has resulted in the loss of over 27% of the world’s coral reefs which is an alarming rate. This has put conservationists, biologists, and other experts into a frenzy to find the innovative ways to tackle the effects of coral bleachings which is happening on a global level. A recent study might have the answer hidden in the genetics of the coral reefs.

According to a research paper concluded by the Stanford University under its Stanford Medicine project which is published in the journal Proceedings, a genetic editing tool named as CRISPR-Cas9 has proven to have emphasis over modification of coral genes to help them survive the soaring ocean temperature. Phillip Cleves, a Stanford geneticist elaborate the research as per which, CRISPR-Cas9 has successfully shown evidence as a gene-editing tool on corals which is marked as a great resource for biologists studying the corals.

Although it is under its early stage or as said, ‘early blueprint’ of what could be achieved in the future with further studies, gene-editing tools can help to study coral genome. It will facilitate the geneticists to study the gene correlated to the survival of the corals as well as genes responsible for establishing colonies or those which can be more resistant to the soaring ocean temperatures. The team of researchers under Stanford Medicine project conducted the study on Acropora Millepora corals in which, they were able to modify three types of genes: green fluorescent protein, red protein, and fibroblast growth factor 1a.

What the scientists did was to tweak the extracted genes and turn it off using the gene-editing tool CRISPR-Cas9 where the first two were tricky while the third proved to have a significant result. To elaborate, the first two genes in the coral genome had many copies or replicas where if the scientists switched off anyone copy, it won’t affect the overall output. This is where researchers had to engross and perform an extensive gene editing to tweak the replicas. The results were molecular but great as the corals didn’t lose any fluorescence but when they did DNA sequencing, the results were pretty impressive in molecular level.

The third gene in question – fibroblast growth factor 1a had only one copy in the coral genome was successful and the coral embryos showed signs of mutation. During the study, the researchers had to keep a close watch towards zygote-collecting process since corals spawning occurs just twice or maybe just once a year and under the rise of a full moon. For the purpose of collecting the fertilized egg or zygote, researchers at Stanford University took help from the Australian Institute of Marine Science for help.

Researchers already tagged the CRISPR-Cas9 has an early blueprint, however, it has a potential to curb the bleaching effects by targeting genes involved. Coral bleaching is an event which is triggered when the sea surface temperature rises which induces the corals to excrete the algae collected on the surface [which are responsible for pigmentation]. This results in corals turning into white colored corals. With the rise of bleaching events, it is expected that in coming years, there will be no ‘colorful’ corals left and only a plain specific species of corals with resistance against rising temperature would survive.

Now, researchers are studying the future prospect of the gene-editing tool to target genes which cause skeletal growth and also, survival of the corals. This will also help the researchers to understand all the important genes and the way to conserve it effectively.