AP Biology class blog for discussing current research in Biology

Author: frantibiotic

Cute Pigs Save the Day

Here, we might see two cute pigs having a lovely time, but biologist Luhan Yang sees otherwise; she sees life-saving organs!

With her remarkable Harvard background in genome-editing and bioengineering, Luhan Yang plans to use CRISPR to create pigs whose organs can be transplanted into people.

With miracles come challenges, which Luhan Yang faces a lot of! Luhan Yang is putting in front of herself the challenging of CRISPR’ing an unprecedented number of genes without being sure of the outcome. There is also the issue of money that needs to be raised.

Astonishingly, in 2015, Luhan Yang and her colleagues used CRISPR to eliminate 62 genes from pig cells that would have been dangerous they had been transplanted into humans. In March of 2017, Luhan Yang and her company, eGenesis, have raised $38 million from investors. These milestones have led Luhan Yang and her team to approach a new step where they get a surrogate mother that becomes pregnant with genetically altered embryos.

As successful as this idea sounds, Luhan Yang and her research team have stumbled upon many problems. One of them being the PERV genes that are interwoven into the genome of pig cells. In order to remove these genes though, the team uses CRISP-Cas9 to remove these genes. With these newly-edited cells, eGenesis ships many of these cells to China where each de-PERV’ed pig cell is fused with a pig ovum whose own DNA has been removed; this ova now contains solely the PERV-free genome. Unfortunately, all has not gone well as there have unfortunately been a lot of miscarriages and not all of the PERV-genes have been removed. Regardless of these setbacks, Luhan Yang is confident that she will make progress with her ideas and will push the limit of genomic technology.

Eat Your Veggies!


An extraordinary research team from The Francis Crick Institute has discovered, from their new study, that chemicals produced by vegetables — kale, broccoli, cabbage, etc. — could help in maintaining a healthy gut and in preventing colon cancer.

The new study was tested on mice, and the goal was to see whether or not vegetables had an effect on maintaining a healthy gut. Spoiler alert, the new study was fairly successful for the mice!

To do this experiment, the research teams used genetically modified mice that could neither produce or activate aryl hydrocarbon receptor (AhR), a protein, in their guts. These mice were either put in a purified control diet — a diet that contains the exact mixtures of carbohydrates, proteins, fats, and fibers enriched with vitamins and minerals — or on the standard diet/I3C-enriched food. I3C is essential to the body because it can prevent colon inflammation and cancer by activating AhR.

Once the study was completed, the researchers found that AhR is vital for repairing damaged epithelial cells; “Without AhR, intestinal stem cells fail to differentiate into specialized epithelial cells that absorb nutrients or generate protective mucus. Instead, they divide uncontrollably which can ultimately lead to colon cancer.” Ultimately, the standard diet/I3C-enriched food, or in other words, a vegetable-rich diet, is the better diet since it helps with our intestines.

Overall, with this new and encouraging discovery, the research team is planning to do further experiments in organoids made from human gut biopsies and then eventually do human trials. Although we have made a discovery simply for mice, this discovery is very helpful and leads us to a good path to cure cancer.

The United States Plays a Role in Changing our Bodies

Researchers at the University of Minnesota and the Somali, Latino, and Hmong Partnership for Health and Wellness have new evidence that the gut microbiota of immigrants and refugees rapidly Westernize after their arrival in the United States.

In order to accomplish this research, the researchers used a community-based participatory research approach from Minnesota’s large community of refugees and immigrants from Southeast Asian (particularly the Hmong and Karen people, ethnic minorities originally from China and Burma that mostly now live in Thailand). These immigrants and refugees were involved with designing the study.

A concern that has been relevant in the communities of refugees and immigrants was obesity. With this in mind, the researchers wanted to see if there is a relationship with immigrants and obesity.

The team of researchers compared the gut microbiota of Hmong and Karen people still living in Thailand; Hmong and Karen people who had immigrated to the U.S.; the children of those immigrants; and Caucasian American controls.

With this, the researchers found that there were significant changes in just the first six to nine months! The Western strain bacteroids began to displace the non-Western bacteria strain Prevotella. The more interesting part is that this Westernization continued to happen in the next decade, and so on. Overall, as the immigrants and refugees spent more time in the U.S., the diversity in the microbiome started to decrease. Indeed, the changes were even more pronounced in their children.

Overall, participants’ food logs suggested that eating more Western food played a role in changing the microbiome, but could not explain changes in the body, like obesity. So, we are still left with some wonder, but scientists will soon put our wondering to an end!


A Treat for the Muscles!

Scientists using CRISPER-Cas9 gene-editing technique have managed to better the lives of four dogs suffering from the most common form of muscular dystrophy, Duchenne.

A research team led by U.T Southwestern Medical Center edited muscle cells in young dogs with Duchenne to remove a short, problematic segment of protein-coding DNA that occurs in both canine and human patients. Within about two months, the dogs were producing a greater amount of dystrophin.

To get this gene-editing technology into the dog’s muscles, the research team created viruses to transport the gene-editing machinery. To do so, the scientists had to extract some of the virus’s own DNA in order to fit the gene-editing machines. The viruses were assigned either of two tasks. Some viruses carried Cas9-molecular “scissors” to cut out the DNA sequence that blocks the production of dystrophin in muscle cells. The other viruses carried a guide molecule to help the Cas9 to identify where it should make those cuts.

Using viruses as a means to transport the gene-editing technology is very helpful because viruses are very small, even smaller than bacteria. When a virus enters your body, it invades some of the cells and takes control of the cell’s functions by injecting its genetic materials into the cell.

For now, the research team has already demonstrated that CRISPR can treat Duchenne in human cells in the lab, but this test was the first success with a large mammal. Adding on, for this study, the research team focused on the protein level, not on how this treatment may have affected the dog’s behavior.

To conclude, one question that remains in the air after this demonstration is how long one injection with CRISPR will last in human Duchenne patients versus dogs. The research team is hoping once, but there is still so much to discover!

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