A Mutation That Makes Horses Athletic

     Horses are known to be very fast animals. Johns Hopkins Medicine researched and discovered how horses are so quick. Horses override a genetic "stop" sign which allows them to generate high energy to provide them with oxygen during exercise.  This method has only ever been seen before in viruses.

    The researchers discovered a mutation in the KEAP1 gene in horses, donkeys, and zebras. This mutation introduced a stop codon. However, if the codon appears early in a gene, the protein produced may not function correctly. Horses are able to recode the stop codon and allow their KEAP1 protein to be fully functional.

    Horses have an adaptation in their KEAP1 gene that makes the protein more reactive to oxygen which makes their NRF2 protein more active. The researchers concluded that this adaptation and mutation are the reason horses are able to fuel their body with enough oxygen when performing intense exercise.

Figure 1. Horse Running 

    This research does not only prove why horses are able to run so fast for so long, but it allows scientists to better understand chronic diseases, age related diseases, and exercise physiology.  Premature stop codons, like the stop codons seen in horses, account for 11% of inherited diseases such as cystic fibrosis and muscular dystrophy.  

    Overall, this study provided insight on the genetic make up of horses and how they are athletic but it also helps the future of inherited and age related diseases. I learned a lot about how horses function when exercising and how stop codons and be bypassed because of mutations from this article. I did not expect that this information on horses can be helpful in understanding chronic diseases. Hopefully this research allows scientists and doctors to better know their patients functions of genes to help treat their diseases. 

Can Your Gut Bacteria Influence Behavior?

 A recent study by Communications Biology explores how the gut microbiome may play a role in animal domestication by influencing behavior. Using foxes from the Belyaev Farm-Fox Experiment, researchers compared gut bacteria between “tame” foxes (friendly toward humans) and “aggressive” foxes.

They found that tame foxes had lower gut microbial diversity and a reduction in bacteria linked to fear and aggression. Additionally, the microbiome of tame foxes showed enrichment in pathways like glutamate degradation, which is important because glutamate is a neurotransmitter involved in brain signaling and behavior.

Since all foxes were raised in the same environment and given identical diets, these differences suggest that behavioral selection (tameness vs aggression) is linked to changes in the gut microbiome, not just genetics or environment. The study highlights the importance of the microbiota–gut–brain axis, a system where gut microbes can influence brain function through metabolites, immune signaling, and even gene expression. 

I think this is really interesting because we usually think behavior is controlled only by genes or the brain, but this shows that bacteria in your gut might also play a role. It kind of changes how we think about evolution and domestication—not just as changes in DNA, but also changes in the microbiome.

Source: https://www.nature.com/articles/s42003-026-09717-5

Additional Source: https://my.clevelandclinic.org/health/body/25201-gut-microbiome

Why NDMA Contamination is More Dangerous for Children Than Adults

 

Figure 1. DNA adducts led to an increase in double-stranded DNA breaks in juvenile mice, ultimately leading to the development of liver cancer.



   An MIT study uncovers that NDMA-contaminated drinking water is more likely to significantly impact children than adults. NDMA (N-Nitrosodimethylamine) is a toxic byproduct generated by many chemical processes and is also contained in cigarette smoke and processed meats. The study was prompted by the recent discovery of NDMA causing cancer in 22 children between 1990 and 2000 in Wilmington, MA. A chemical site called Oiln Chemical Superfund Site was operating in this area and contaminated the town water supply with chemicals containing NDMA.

   In usual studies, adult mouse models at least 4 to 6 weeks old are used to evaluate potential carcinogens, while younger mouse models are typically not included. This exclusion makes the health effects on a developing younger generation remain unknown. Therefore, the MIT researchers used two groups of mice - one 3 weeks old (juvenile) and one 6 months old (adult). Each group drank water with low levels of NDMA for two weeks. As a result, the livers of both juveniles and adults experienced the same initial levels of DNA damage (known as adducts) caused by a liver enzyme called CYP2E1, which metabolizes NDMA. However, in juvenile mice, the rapid rate of cell division in the liver caused these DNA adducts to transform into double-stranded DNA breaks and mutations before the body could repair them, consequently resulting in high rates of liver cancer. In contrast, the adult mice, whose liver cells divide much more slowly, showed almost no double-stranded breaks and did not develop tumors despite being exposed to the same level of NDMA. This study ultimately emphasizes the need to evaluate the impacts of environmental carcinogens among all age groups to better protect public health.



Links:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8361697/

https://www.news-medical.net/news/20260417/Study-explains-the-link-between-NDMA-contaminated-water-and-childhood-cancer.aspx



Tags: #NDMA #Cancer #Contaminated-water #Massachusetts

A Rare Gene Variant Contributing to the Development of Alzheimer’s

 

   MIT neuroscientists have identified rare variants of a gene called ABCA7. These rare variants, when dysfunctional, contribute to the development of Alzheimer’s disease in people who already carry it. ABCA7 encodes a protein that transports lipids across the cell membrane. The mutations of ABCA7 alter the metabolic activity of a molecule called phosphatidylcholine. These mutations cause neurons to become hyperexcitable, damaging DNA and other crucial cellular components. However, researchers have discovered a way to reverse this with choline, a protein precursor that helps build cell membranes. With choline treatment, not only are the functional defects reversed, but hyperexcitability also decreases. Additionally, individuals carrying ABCA7 variants that produce low levels of functional ABCA7 have twice the risk of developing Alzheimer’s compared to those not carrying the variants. The study revealed the importance of ABCA7 in maintaining lipid homeostasis in the brain.



Links:

https://pmc.ncbi.nlm.nih.gov/articles/PMC12728103/

https://news.mit.edu/2025/study-explains-how-rare-gene-variant-contributes-alzheimers-disease-091



Tags:

#ABCA7 #Neurons #LipidHomeostasis #Alzheimer’s

Often Missed, Rare Disease Diagnosis Are Now Detected by New RNA Sequencing Platform

 

   Researchers at the Children’s Hospital of Philadelphia (CHOP) have applied long-read RNA sequencing at scale to discover disease-causing variants in pediatric patients, helping to detect rare diseases. This versatile, low-cost sequencing tool is called STRIPE (Sequencing Targeted RNAs Identifies Pathogenic Events). Its novel diagnostic workflow allows researchers to identify diagnoses missed by other genetic tests and to discover unexpected molecular insights into previously identified pathogenic variants. 

   While exome and genome sequencing are most commonly used to identify genetic variants responsible for rare diseases, these tools have a diagnostic yield of only 20% to 50%, signifying that over half of the patients with suspected rare diseases are unable to receive a molecular diagnosis. However, with the implementation of long-read sequencing, scientists can observe how genetic variants disrupt function in real-time by capturing full-length RNA molecules end-to-end, showing complex errors in RNA processing that traditional fragmented sequencing methods miss. Ultimately, STRIPE is capable of improving the diagnosis of rare diseases and helping patients receive the targeted therapy needed.



Links:
https://pubmed.ncbi.nlm.nih.gov/41984969/

https://www.news-medical.net/news/20260415/New-RNA-sequencing-method-improves-rare-disease-diagnosis.aspx



Tags: #STRIPE #Long-read #RNA-sequencing #Diagnosis

The First Bacteriophage Generated by AI

Figure 1. The diagram above depicts the genomic and structural architecture of ΦX174-like bacteriophages, which specifically target E.coli.



​   Genomes encode complex interactions that express vital biological functions. With the assistance of two Artificial Intelligence (AI) models, viable bacteriophage genomes have been generated by computational biologist Brian Hie and other colleagues from Stanford University. A mixture of these AI-generated bacteriophages prevented virus-resistant Escherichia coli (E.coli) from growing. Hie and his colleagues leveraged two AI genome language models, Evo 1 and Evo 2, to develop entire genome sequences with realistic genetic structure and desirable host characteristics, using the lytic phage ΦX174 as the design template. Bacteriophage ΦX174 was the first DNA-based genome ever. It was sequenced back in 1977 and has been well researched, with a wide range of information published on it.

   Experimental testing of the AI-generated genomes by Evo 1 and Evo 2 produced approximately 300 potential phage genomes, but only 16 of them were viable with substantial evolutionary originality. These 16 phage genomes produced viable viruses that could infect E.coli. Multiple phages demonstrated higher fitness than ΦX174 in growth and lytic strength. Furthermore, a combination of the AI-generated phages rapidly overcame ΦX174-resistance in three E.coli strains, highlighting the potential for designing phage therapies against rapidly evolving bacterial pathogens.



Links:

https://www.sciencenews.org/article/ai-genome-bacteria-phage

https://arcinstitute.org/news/hie-king-first-synthetic-phage



Tags: #AI-generated #Bacteriophage #Antibiotic-resistant #Bacterial-infection #E.coli

The Amazon Molly: An All-Female Fish Species with a DNA Repair Survival Trait

  

Figure 1. A group of Amazon molly (Poecilia formosa) huddled together, all a mirror image of each other due to cloning and genetic conversion.

     A unique cross-species mating from nearly 100,000 years ago between a female Atlantic molly (Poecilia mexicana) and Sailfin molly (Poecilia latipinna) birthed a hybrid called the Amazon molly (Poecilia formosa) - an all-female species. While the mating of the two different species should have produced a sterile offspring, a hybrid animal that is unable to reproduce themselves, the Amazon molly possesses the ability to birth genetic clones of herself. Through an asexual reproduction process called gynogenesis, the Amazon molly mates with closely related males to trigger embryonic development. While the male’s sperm is required for the reproduction of the embryo, the male’s genetic material is bypassed and not inherited by the offspring.

     Generations of clones often lead to extinction due to a lethal amount of mutations developed over time. However, scientists in 2018 sequenced the Amazon molly’s genome, uncovering a few signs of genomic degradation. Due to limited DNA sequencing technology, the reason why the Amazon molly had not experienced genetic decay was not discovered until later on, when technology that could precisely separate the fish's paired chromosomes to assess each of the ancestral parental genes was created. As a result, the scientists discovered that the Amazon molly eliminates harmful mutations through a DNA repair process known as gene conversion, where one DNA sequence replaces a homologous sequence. While the Amazon molly still accumulates mutations at a faster rate than sexually reproducing species, the discovery of this fish’s gene conversion during asexual reproduction has highlighted the advancement of sequencing tools and the ability to study mutations and genome evolution in a more precise manner.



Links:
https://www.sciencenews.org/article/sex-skipping-fish-hacks-evolution-gene

https://www.science.org/content/article/genetic-trick-helps-all-female-fish-species-escape-evolutionary-doom

Tags: #Cloning #Geneconversion #Amazonmolly #Asexualreproduction #All-femalespecies

Modern Humans Came From at Least 2 Ancestral Populations

By analyzing the genome sequences, researchers found that modern humans are the result of 2 populations that diverged 1.5 million years ago. It has long been believed that Homo sapiens first appeared 2-300,000 years ago from a single lineage. The latest results reveal that once the 2 populations diverged, they came back together in an admixture event around 300 thousand years ago, in a ratio of 80:20%. This data shows a strong bottleneck in the major ancestor, while the minority correlates to distance to coding sequence, suggesting a deleterious effect on the majority population. Interbreeding and genetic exchange has long played a major role in the emergence of new species across the animal kingdom.

Sources:

 https://www.nature.com/articles/s41588-025-02117-1 

https://www.sciencedaily.com/releases/2025/03/250318141412.htm