Tag Archives: mutation

Rare genetic mutation results in stunning blue-skinned frog

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The magnificent tree frog (Litoria splendida) is normally green, but this mutant is blue

J Barker/AWC

A rare blue frog found in the Kimberley region of Western Australia has stunned researchers who say the unusual colouring is probably due to a genetic mutation causing it to lose certain skin pigments.

As its name suggests, the magnificent tree frog (Litoria splendida) is already a spectacular animal, so when Jake Barker When he saw a bright blue specimen on a bench in a workshop at the Australian Wildlife Conservancy’s Charnley River-Artesian Range Wildlife Sanctuary in April, he was shocked.

The amphibians are normally a vibrant green, which is a common colour for tree frogs and is thought to camouflage them.

“I knew as soon as I saw it that it was rare,” says Barker. “It’s not often that you get to see a blue frog.” It has been seen a number of times since, but won’t be captured for research, he says.

“It’s far too pretty and far too unique and it would be a pity to take it away from its natural habitat,” says Barker. “We’ll leave it to live out its days and hopefully get to see it many more times in the future.”

Jodi Rowley At the Australian Museum in Sydney, the animal may be the “most beautiful, aberrant-coloured frog” that she has ever seen. “And I have seen tens of thousands of frogs.”

From the photos she has seen, Rowley says the frog is at least 2 to 3 years old. The species may live to be 20 years old, so the blue individual is likely to be around for a while unless caught by a predator.

She says the frogs’ skin colour is determined by the combination of three chemicals – melanophores, which provide blacks and browns; xanthophores, which provide yellow pigments; and iridophores, which reflect blue colours. Normally, the yellows and blues combine to make green, but it is thought the new blue frog has a mutation that means it is missing the yellow pigments and the blue dominates.

“Blue is probably a bit more obvious to predators,” says Rowley, “which is why we don’t see many blue frogs.”

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Source: www.newscientist.com

A unique mutation linked to short stature may hold clues to understanding the aging process

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Two of the researchers and several study participants with Laron syndrome

Jaime Guevara-Aguirre and Bartel Longo

People with rare genetic mutations that cause short stature and may even live longer are helping to understand the causes of aging.

People with unusual genetic mutations have some characteristics that protect them from heart disease, one of the most common causes of death, and this explains why their life expectancy exceeds that of the general population. You may have.

A signaling molecule called insulin-like growth factor-1 (IGF-1) has long been suspected to be involved in longevity. Several animals, including worms and mice, have been shown to live longer when their levels of this compound are artificially lowered, such as through genetic modification. Centenarians also have slightly lower IGF-1 levels,on average.

In most species, IGF-1 promotes growth when the animal is young and influences how cells use energy later in life. One idea is that there is a trade-off between animals investing energy in further growth and maintaining health.

“As you get older and your body starts to break down, you want to spend your energy on preventing your body from breaking down instead of spending it on growth,” he says. Nir Barzilai from the Albert Einstein College of Medicine in New York was not involved in the new study.

The question of whether this trade-off also occurs in humans is through a rare genetic disease called Laron syndrome, first identified in a group of Ecuadorians whose ancestors left Spain during the Inquisition centuries ago. can be researched.

This mutation causes people to have defective growth hormone receptors, leading to short stature. People with Laron syndrome also have low levels of IGF-1 because the release of IGF-1 is usually triggered by growth hormone.

Because so few people carry the mutation, it is unclear whether it truly extends lifespan. Suggestive evidence comes from a 2011 study of 90 Ecuadorians with Lalon syndromean estimated 400 to 500 people are affected worldwide.

The researchers found that more people with the disease were surviving longer than expected compared to the general Ecuadorian population. 'We know they are more common in older people' walter longo at the University of Southern California in Los Angeles.

In the latest study, Longo and his colleagues compared 24 people with Laron syndrome from Ecuador or the United States to 27 relatives who did not have the mutation. People with Laron syndrome appeared to be healthier on several heart-related measures, including blood pressure, blood sugar levels, and sensitivity to insulin, a hormone involved in controlling blood sugar levels.

People with this mutation also had higher levels of a compound called low-density lipoprotein. Low-density lipoproteins are also known as “bad cholesterol” because they are thought to make arteries more susceptible to plaque, which can lead to heart attacks. However, only 7 percent of Laron syndrome patients had such plaques, compared with 36 percent of their relatives.

The small number of people in the study means this difference may have arisen by chance, but it does suggest that their arteries appear less unhealthy than those of people without the mutation. suggests, Longo said.

It has also previously been shown that people with Laron syndrome are less likely to develop cancer and may have a lower incidence of cancer. Decline in cognitive function that usually occurs with older age.

This new finding supports the idea that somehow weakening the IGF-1 signaling pathway in later life can slow the aging process. Alexey Maklakov at the University of East Anglia, Norwich, UK. “It's a matter of timing,” he says. “At critical stages of growth and development, you definitely don't want to do that. But later in life, it can interfere with the function of these pathways.”

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Source: www.newscientist.com

Delaying Alzheimer’s Disease with a Genetic Mutation

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Alzheimer’s disease is the most common form of dementia, affecting millions of people worldwide. This disease affects the parts of the brain that control memory, thinking, and language. Most commonly, people with Alzheimer’s disease begin to show symptoms. mid 60’s. Scientists have shown that some rare cases of Alzheimer’s disease are caused by a genetic mutation known as PSEN1-E280A, which causes people to develop Alzheimer’s disease as early as their mid-40s, and that this The condition is called early-onset Alzheimer’s disease.

Scientists have identified a Colombian man who carries the gene for early-onset Alzheimer’s disease and a second genetic mutation called the RELN-COLBOS mutation. This man maintained a fully functioning brain for about 30 years longer than the average person with early-onset Alzheimer’s disease. Scientists hypothesized that his genetic mutation could help develop treatments to help others resist Alzheimer’s disease. But additional case studies were needed to find out whether the genetic mutation was the sole reason for the man’s resistance to the disease.

Researchers in Columbia recently set out to study patients with the RELN-COLBOS mutation to see how it may help fight early-onset Alzheimer’s disease. They enrolled the patient in an international collaboration.Antioch University in Columbia and Massachusetts General Hospital in Boston; called Columbia-Boston Biomarker Research Program.This program includes: More than 6,000 participants took part, including those with and without genes known to cause Alzheimer’s disease.

Researchers compared a Colombian man with the RELN-COLBOS mutation to young-onset Alzheimer’s disease patients who do not carry this mutation to determine whether they develop the disease through different pathways. They compared each patient’s cognitive decline in terms of their motor function, number of neurons firing in their brains, and signal strength. They also measured proteins in each patient’s brain that are known to help with memory and learning, such as Dab1 and Tau proteins.

The researchers also collected brain tissue from the man. They performed a type of genetic profiling called. Single cell RNA sequencing Examining his brain tissue revealed that he PSEN1-E280A Gene that causes early-onset Alzheimer’s disease. They used this same method to determine which RELN mutation he had.

They explained that the RELN gene normally tells the body how to make the protein Reelin, which controls brain development.. This man had a mutation in his RELN gene that codes for a different amino acid. Researchers have observed similar mutations in people with other brain-related diseases such as schizophrenia, bipolar disorder, and autism. They named it the RELN-COLBOS mutation, after their research program.

The researchers then looked at the men’s brains using several medical imaging techniques, including positron emission tomography. PET scanmagnetic resonance imaging, or MRI scan. They examined these images of the man’s brain for signs of disease or other abnormalities.

They found that the men’s brains contained large amounts of amyloid beta protein. They explained that this protein causes the loss of neurons and neural connections in Alzheimer’s patients.But the men’s brains were also found to have lower-than-normal levels of another protein called tau protein, which is usually associated with Alzheimer’s disease.. They explained that Alzheimer’s patients typically have high amounts of the protein tau, which disrupts the internal skeleton of neurons and impairs thinking and memory. The researchers suggested that the man’s low levels of tau protein in his brain were part of his resistance to Alzheimer’s disease.

Based on how the RELN-COLBOS mutation acted in this man, scientists hypothesized that it was the cause. Gain-of-function (GOF) mutations. GOF mutations occur when a mutated gene acquires a new function. In other words, it will work differently than it should. For example, a coffee machine’s function is to make coffee, but a GOF mutation could cause it to start making orange juice instead. They classified the RELN-COLBOS mutation as a GOF mutation because the normal function of the RELN gene is to produce the Reelin protein, but the mutant form instead slows down the production of the tau protein.

The researchers concluded that the new function of the RELN-COLBOS mutation may help the gene regulate neural circuits damaged by Alzheimer’s disease and other types of dementia. However, the researchers cautioned that the mutation’s impact on these diseases is modest, as it slows but does not prevent cognitive impairment. They say there are currently only a handful of cases available and that different genetic mutations may delay Alzheimer’s symptoms in the same patient, so future researchers could study other patients with the same mutations. I suggested that it should be done.


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Source: sciworthy.com

Labradors with a mutation that causes starvation tend to easily gain weight

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About a quarter of Labradors have a mutation in the POMC gene that induces starvation.

Charles Mann/Getty Images

Labradors and flat-coated retrievers, two dog breeds, may be more susceptible to being overweight because they carry mutations that cause them to feel hungry between meals and slow their metabolic rates. “It's a double whammy,” he says. Eleanor Laffan at Cambridge University.

mutations that affect genes called POMCwhich affects about a quarter of Labradors and two-thirds of flat-coated retrievers, but does not affect other breeds.

Discovered in 2016, it was found to alter pathways in the brain associated with weight regulation, but it was unclear exactly how it affected eating habits.

To find out, Laffan's team conducted a “boxed sausage” test on 87 pet Labradors. In this test, dogs were able to see and smell sausages in an impenetrable container. The Labrador dog, in which he had one copy of the mutation, continued to try to open the box much longer than the dog without it.

However, in another test in which dogs were given a can of food every 20 minutes until they ran out of food, all dogs ate the same amount of food, regardless of whether they had the genetic mutation or not. This shows that the mutation affects appetite in a specific way, by increasing hunger levels between meals, Laffan says.

The researchers also measured the resting metabolic rates of flat-coated retrievers while they slept and found that dogs with two copies of the mutation had metabolic rates that were about a quarter lower than other dogs.

Laffan said the effect would be expected to be the same in both breeds, but in a second experiment flat-coated retrievers were more likely to carry both of the mutations than Labradors. He wanted to find out.

Laffan said many other genes probably influence dog weight, just as they do in humans.

Dan O'Neill Researchers from the Royal College of Veterinary Medicine say owners of overweight dogs should avoid giving treats as a way to show affection and instead give their dogs other forms of attention. “You can also replace that snack with a walk,” he says.

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Source: www.newscientist.com

A Unique Patient Mutation Offers New Hope for Preventing Alzheimer’s Disease

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Researchers have discovered a unique case in a Colombian family where a woman with a genetic predisposition to Alzheimer’s disease remained cognitively healthy due to a rare APOE gene mutation, the Christchurch mutation. This mutation disrupts the typical progression of Alzheimer’s disease and suggests new prevention strategies. Dementia may be prevented by breaking the link between early and late stages of the disease.

The disease has plagued one large Colombian family for generations, killing half of them in their prime years. But one member of the family avoided what seemed like fate. She remained cognitively healthy well into her 70s, even though her relatives inherited her genetic defect that caused her to develop dementia in her 40s.

Researchers at Washington University School of Medicine in St. Louis now think they know why. Previous research had reported that the woman was in possession of two copies of the rare variant, unlike her relatives. Apoe A gene known as the Christchurch mutation.

In this study, researchers used genetically modified mice to show that the Christchurch mutation was associated with early stages of Alzheimer’s disease, when a protein called amyloid beta accumulates in the brain, and another protein called tau, which causes cognitive impairment. begins to decline. So the women remained mentally alert for decades, even though their brains were filled with large amounts of amyloid.

“All protective factors are very interesting because they give us new clues about how the disease works,” said lead authors Barbara Barton, Ph.D., and Reuben M. said David M. Holzman, M.D., Morris III Professor Emeritus of Neurology.

Understanding the progression of Alzheimer’s disease, the researches found thatthe main difference was the level of activity of microglia, the brain’s waste-processing cells. Microglia tend to cluster around amyloid plaques. In mice with Apoe The Christchurch mutation activated microglia surrounding amyloid plaques, making them highly efficient at consuming and processing tau aggregates.

Reference: “APOE3ch alters microglial responses and suppresses Aβ-induced tau dissemination and spread” Yun Chen, Sihui Song, Samira Parhizkar, Jennifer Lord, Yiyang Zhu, Michael R. Strickland, Chanung Wang, Jiyu Park, G By Travis Tabor, Hong Jiang, Kevin Lee, Albert A. Davis, Carla M. Huede, Marco Colonna, Jason D. Ulrich, David M. Holtzman, December 11, 2023. cell.DOI: 10.1016/j.cell.2023.11.029

Source: scitechdaily.com