C. elegans may be a model organism for studying telomere biology

    Telomeres, the ends of the double-stranded DNA chromosomes, require proteins for protection. In mammals, shelterin is known to do this important job. Scientists at the University of Michigan have found that the proteins TEBP-1 and TEBP-2 protect the telomeres found in the common roundworm, C. elegans. In order to do their job, these proteins must find a way to bind to each other, and then bind to the chromosome. The worm has "myb-containing domains" known as MCD 1, 2, and 3, which are the three segments of the single proteins TEBP-1 and TEBP-2. The scientists had found that only MCD3 binds DNA to link the proteins to the telomeres while MCD1 and MCD2 bind together molecules of TEBP-1 and TEBP-2. 

    Something mentioned in the article as how before this study, scientists had a lot of trouble trying to find out more of C. elegans due to their tunnel vision. Generally, scientists tend to compare everything to mammals, which can lead to closed-minded thinking. The article reads, "the C. elegans examples shows us that there are multiple ways to solve the end protection problems and some of them might be quite different from how humans do it. But as long as they are effective, they are selected for in evolution" (Science Daily). I thought that was an interesting part to read about in the paper because I think its important to point out errors in perspective or the habit of not thinking open minded. I think in a science setting it is important to keep an open mind because science has proven hundreds of interesting, surprising things before. I also thought it was interesting to read about how one of the lead researchers thinks this roundworm is a model organism for this kind of research. I think its interesting how the roundworm added so much information about chromosome ends and telomeres considering how microscopic the actual animal is. Overall, I thought it was interesting to see how different our DNA works compared to a roundworm and how scientists come about this information. 

 https://phys.org/news/2024-04-elegans-chromosomes.html#:~:text=Nandakumar%20says%20that%20because%20you,organism%20for%20studying%20telomere%20biology. 

https://www.sciencedaily.com/releases/2024/04/240408150446.htm 

Hermaphroditic roundworms lose half their genome from sister species when self fertilizing

An article done by the New York Times describes how tiny roundworms, Caenorhabditis briggsae and Caenorhabditis nigoni are extremely similar genetically, but very different in their sexual reproduction processes. In order for C. nigoni to mate, there needs to be a male and a female for fertilization to take place. This is different for C. briggsae however, in that they are able to self-fertilize by producing sperm to fertilize their own eggs. Because C. briggsae are hermaphroditic, there is no need for sexual reproduction. This genetic adaptation has occurred because there is a lack of males in the population. In a study published in Science in the beginning of January of 2018, biologists found that since the hermaphroditism took place in the one set of roundworms, it lost half of the genes since it broke away from C. nigoni approximately a million years ago. A study done by the University of Maryland-College Park concludes that this loss of genes is related to the male population which is dwindling in numbers. When introduced to the male secreted short genes (m.s.s.), C. briggsae produced more offspring than the hermaphroditic organisms. Dr. Haag from the University of Maryland-College Park suggests that these organisms leaning towards hermaphroditic lifestyles may “put a break on population”.


This article I found very interesting. It’s neat to see how hermaphroditic traits in one roundworm compared to their ancestral sister alter their entire genome. Although the roundworm C. briggsae do not yield as many offspring through self-fertilization unlike if they were to be in contact with a male, it provides evolutionary traits in that population growth and size can be halted/reduced. It’s also hard for these worms to find mates as well, which make it hard for new colonies of C. briggsae to get started.

(Related Article)

Alcoholism Has To Do With Genetics

In the article, “Link between genetic variation, alcohol dependence found” in Science Daily, they found information that may explain how alcoholism is partly because of genetics. Many people have problems with alcohol use and many of the people go untreated. It is estimated that 18 million people in the United States have such a problem. The treatments that they have for alcoholism are scarce and not that helpful because of the genetics behind it. If they understood the genetics of alcoholism they could make a more effective treatment and even tell if people are more susceptible to alcohol abuse. The researches examined switching defective/sucrose nonfermenting (SWI/SNF) in roundworms. They chose roundworms because their genetic make up is similar to ours. They found that the alcoholism is because of mutations in many genes. Each mutation is a small mutation, but when they add up they can be the reason for alcohol dependence. The same effects in worms are seen in humans, so they just need to do further research.

Alcoholism is a very serious disease. Many people are affected by it and many people do not want to admit that they have a problem. Like many other things, some people have a higher disposition to certain things. And I definitely think that some people are more susceptible to alcohol dependence than others through genetics. There are many families that have alcoholism that runs in the family. If they could find out where the mutations are occurring then many people can receive help that is accurate and effective. If they continue to do research, I think that we can find a new effective treatment soon.

One Worm, Two Mouths

Researchers at the Max Planck institute for evolutionary biology in Germany are now able to explain how organisms such as the roundworm adapt to their different surrounding conditions. Depending on the environment in which the roundworm grows, the larva develops into a short or narrow mouthed bacteria eater or a wide- mouth predator. This is not dependent on its gene. They did find a gene which functions like a switch and selects the variant of two possible mouth forms. 

            The gene eud-1 is sulfatases which are enzymes that chemically alter other proteins or molecules. With this discovery, and genetically introducing   additional copies of the edu-1 gene almost all the transgenic worms developed the wide mouth with characteristic tooth.  The change of their development has been created by the changing demands of their environment which is called “phenotypic plasticity”. That is also explained by the evolutionary adaptation.

This is a heated debate among evolutionary biologists.  It will be interesting how this discovery will change the face of Darwin’s natural selection.  With the discovery of the switch gene it will just cause more of a fire for the long battle between genes and environment.

http://www.sciencedaily.com/releases/2013/11/131107123146.htm

http://www.mpg.de/7602474/roundworm-mouth

 

 

The Genetics of a Cell's Natural Defense

For years there has been debate and question over just exactly how cells in our bodies fight off disease and infections. The "Immune System" is a broad range of mechanisms and devices within the human body that keep us healthy. However, in a study conducted UC San Diego, the immune defense of intestinal cells was studied. Using the roundworm  C. elegans, scientists were able to study the exact mechanisms of how infection was fought. The worm was ideal for the study because of its physical transparency, and similarity to human cells.

[caption id="" align="alignleft" width="360" caption="A Cell's Immune System at Work"][/caption]

It was found that the cell's defense depended on the availability of certain transcription factors. Since the "infection" would inhibit the normal activity of the roundworms cells, once proteins stopped being synthesized, antibiotic defense factors were released by the cell. It was determined by this study that the inhibition of protein synthesis in the roundworm directly expresses the cell's defense genes. Scientists and experts estimate that many other similar chemical pathways exist, and that certain toxins, nutrients, and other materials may express certain genes.