AP Biology class blog for discussing current research in Biology

Tag: generations

Does Exposure to Toxins In the Environment Affect One’s Offspring’s Immune System?

A study has recently surfaced stating that maternal exposure to industrial pollution may harm the immune system of one’s offspring and that this impairment is then passed from generation to generation, resulting in weak body defenses against viruses.

Paige Lawrence, Ph.D., with the University of Rochester Medical Center’s Department of Environmental Medicine, led the study and conducted research in mice, which have similar immune system functions as humans. Previously, studies have shown that exposure to toxins in the environment can have effects on the respiratory, reproductive, and nervous system function among generations; however, Lawrence’s research is the first study to declare that the immune system is also impacted.

“The old adage ‘you are what you eat’ is a touchstone for many aspects of human health,” said Lawrence. “But in terms of the body’s ability to fights off infections, this study suggests that, to a certain extent, you may also be what your great-grandmother ate.”

“When you are infected or receive a flu vaccine, the immune system ramps up production of specific kinds of white blood cells in response,” said Lawrence. “The larger the response, the larger the army of white blood cells, enhancing the ability of the body to successfully fight off an infection. Having a smaller size army — which we see across multiple generations of mice in this study — means that you’re at risk for not fighting the infection as effectively.”

In the study, researchers exposed pregnant mice to environmentally relevant levels of a chemical called dioxin, which is a common by-product of industrial production and wast incineration, and is also found in some consumer products. These chemicals eventually are consumed by humans as a result of them getting into the food system, mainly found in animal-based food products.

The scientists found the production and function of the mice’s white blood cells was impaired after being infected with the influenza A virus. Researchers observed the immune response in the offspring of the mice whose mothers were exposed to dioxin. Additionally, the immune response was also found in the following generations, as fas as the great-grandchildren (or great- grandmice). It was also found that this immune response was greater in female mice.  This discovery now allows researchers to have more information and evidence to be able to more accurately create a claim about this theory.

As a result of the study, researchers were able to state that the exposure to dioxin alters the transcription of genetic instructions. According to the researchers, the environmental exposure to pollutants does not trigger a genetic mutation. Instead, ones cellular machinery is changed and the immune response is passed down generation to generation. This discovery explains information that was originally unexplainable. It is obviously difficult to just avoid how much toxins you are exposed to in the environment, but it is definitely interesting to see the extent of the immune responses in subsequent generations. We can only hope that this new information, and further discoveries, help people adjust what they release into this world that results in these harmful toxins humans are exposed to, and their offsprings.




Wait, Babies can be Born Without Eyes?

This picture displays a baby with healthy eyes!

This photo was found on through Google Advanced Search

I always knew individuals could lose eyes if a terrible accident occurs, but I never knew that babies can be born without eyes! Did you?

Recently, a condition called anophthalmia has been discovered. It is when there are complications with the development
of both copies of the STRA6 gene, one that is “responsible for transporting vitamin A into the cells.” In fact, vitamin A is needed for the development of every inch of our retina, a tissue lining the inside of the eye. In less scientific terms, anopthalmia is when an individual is born with the loss of one or both eyes. Microphthalmia, a condition where an individual has small eyes, and coloboma, which is a deformed eye, are two other eye conditions that develop in a baby while he or she is still in the womb. These three diseases make up eleven percent of all eye deformations. However, the Micro & Anophthalmic Children’s Society UK reported that microphthalmia and coloboma are much more common than anopthalmia.

Doctors like Dr. Sean Ennis from the UCD School of Medicine and Medical Science, University College Dublin, and the National Centre for Medical Research started researching the perplexing idea that babies can be born without eyes with “nine individuals from across several generations of an Irish ethnic minority family of nomadic descent who suffer with one or more of the three eye defects to varying degrees of severity.”
Dr. Ennis says,


“Using advanced gene sequencing technologies, we firstly scanned for regions of DNA shared by all patients before analysing a single common region for the disease gene. From this we pinpointed STRA6, a gene responsible for transporting vitamin A into cells.


In the past, doctors have found that alterations and complications of the STRA6 gene in DNA can cause Matthew-Wood syndrome. This is a disease that can cause irregular eye formation and hardships for development in general.
Scientists of the University College Dublin, Ireland, in addition to doctors such as Dr. Hui Sun and Dr. Riki Kawaguchi of the University of California, actually made this fascinating discovery recently. Now, they are attempting to make genetic testing to determine whether a baby in a mother’s womb will have anopthalmia early on. They would really like to develop a clinical practice, which would take place at the National Centre for Medical Genetics (NCMG) in Dublin. Professor Andrew Green of University College Dublin says,

“Accurate carrier testing and genetic counselling can be offered to those individuals planning to have children. And ultimately, this work may be used to develop preventive measures or possible treatments in the future,”

As of right now, babies born with small eyes, deformed eyes, or no eyes must get prosthetic eyes to help them see and help the development of other parts of their bodies, including the face and skull. Eye defects can also be associated with birth defects and deformations in the heart, lungs, and diaphragm. We must hope for progress in the research and clinical trials for anophthalmia, so that the malformation and lack of eye disorder disappears forever one day!

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