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Category: genetics – Page 459

New techniques better determine how ancient viral DNA influences human genes

For decades after the discovery of DNA, researchers mostly thought of genetics in terms of genes, the pieces or sequences of DNA that encode instructions for building proteins in cells. Then scientists discovered that genes make up just 2 percent of our DNA and that most genetic complexity stems from the vast non-gene code, which influences when genes are turned on or off. Further, half of that non-gene code was found to come from insertions of viral DNA. Consequently, say the authors, genetic variation, and the potential for disease-causing mistakes, occurs in transposons as well as in genes.

New laboratory techniques can identify which of our genes are influenced by DNA snippets that are left behind in our genetic code by viruses, a new study finds.

Biologists shed new light on the diversity of natural selection

Evolutionary genetic theory shows that genetic variation can be maintained when selection favors different versions of the same in males and females—an inevitable outcome of having separate sexes. That is, for many genes, there may not be a universally ‘best’ , but rather one is best for males and one is best for females. This is known as sexually antagonistic genetic variation, but it might only be maintained under a narrow set of conditions, limiting its prevalence in nature. However, a new study by Dr. Karl Grieshop and Professor Göran Arnqvist, published in PLoS Biology, may change this view.

“One of the simplest ways for sexually antagonistic selection to maintain genetic variation in is via sex-specific dominance reversal, where neither version of a gene is always dominant or recessive, but rather the version that benefits a given sex is also dominant in that sex. So whether a given version of a gene is dominant or recessive to the other will depend upon which sex it is in,” says Dr. Karl Grieshop.

Gene study unravels redheads mystery

Eight genes linked to red hair have been discovered by scientists, helping to shed light on how redheads inherit their distinctive locks.

The Edinburgh University-led research has been described as the largest genetic study of hair colour to date.

It had been thought red hair was controlled by a single gene, MC1R, with versions passed on from both parents.

Rapid genetic evolution linked to lighter skin pigmentation in a southern African population

Populations of indigenous people in southern Africa carry a gene that causes lighter skin, and scientists have now identified the rapid evolution of this gene in recent human history.

The gene that causes lighter pigmentation, SLC24A5, was introduced from eastern African to southern African populations just 2,000 years ago. Strong positive selection caused this gene to rise in frequency among some KhoeSan populations.

UC Davis anthropologist Brenna Henn and colleagues have shown that a gene for lighter skin spread rapidly among people in southern Africa in the last 2,000 years.

Scientists May Have Halted Blindness Caused by This Rare Genetic Disease

D esigner therapies are treatments tailored to a specific disease, and nowhere is the need greater for new therapies than in a group of nervous system disorders, known as “neurodegenerative diseases.”

Many of these diseases are common and well-known, such as Alzheimer’s or Parkinson’s disease. However, some are very rare, genetic disorders that are the consequence of a defective gene. In all these diseases, a mutant protein that misfolds causes the degeneration and death of neurons. One effective therapeutic strategy is to prevent the rogue protein from ever being made.

Spinocerebellar ataxia type 7 (SCA7) is one such disease in which nerves in different parts of the brain, including the eye, degenerate, which leads to blindness and difficulty walking, speaking, and balancing. SCA7 is dominantly inherited — which means that you just need one bad copy of the mutation to cause disease. The disease occurs when a short section of DNA that encodes ataxin-7 gene is erroneously repeated — like a word in a book printed two or three times. In this case, three chemical units of the DNA sequence — C-A-G — are repeated over and over.

Regenerage — SMX Radio — The Net of Regenerative Medicine — Bioquark

Dr. Joel I. Osorio of RegenerAge Clinic on SMX Radio broadcasting from the Colonia Santa María la Ribera neighborhood of Mexico City -
“LAS NETAS DE LA MEDICINA REGENERATIVA” (The Net of Regenerative Medicine)
Spreading the gospel of human regeneration, repair, and rejuvenation to the world — https://www.facebook.com/SMXradio/videos/751646811869501/

FDA Approves Drug That Targets Key Genetic Driver of Cancer

Imagine one drug that can target and kill malignant cells for some patients with many types of cancer. A new drug called Vitrakvi (larotrectinib), now approved by the U.S. Food and Drug Administration, shows promise of doing just that for both adults and children with a variety of sometimes rare cancers that share one specific genetic mutation.

The mutation, called a TRK fusion, occurs when one of three NTRK genes becomes mistakenly connected to an unrelated gene and ignites uncontrolled growth. By solely targeting this mutation, the drug is designed to turn off growth signaling with a minimum of other toxicities.

According to the drug manufacturer, Loxo Oncology, this specific mutation can occur in a small subset of various adult and pediatric solid tumors ranging from cancers of the appendix, bile ducts, breast, lung, pancreas and thyroid to melanoma, GIST and various sarcomas.

Double the stress slows down evolution

Neoliberalism slows down evolution! Just kidding…or am I? 🧐😁🤣🙈.

Like other organisms, bacteria constantly have to fight to survive in hostile living conditions. Together with colleagues in Finland, researchers at the Max Planck Institute for Evolutionary Biology in Plön have discovered that bacteria adapt to their environment more slowly and less efficiently as soon as they are exposed to two stress factors rather than one. This is due to mutations in different genes. The slower rate of evolution led to smaller population sizes. This means that evolution can take divergent paths if an organism is exposed to several stress factors.

Bacteria rarely live alone; they are usually part of a community of species that is exposed to various stress factors. They can often react to these factors by adapting to new environmental conditions with astonishing speed. Antibiotics that enter soil and water via and accumulate there in low concentrations can trigger the evolution of resistance in – even though these concentrations are so low that they inhibit only slightly or not at all. However, bacteria do not only have to fight ; they also have to deal with predators. This is why they often grow in large colonies that cannot be consumed by predatory organisms.

Typically, scientists investigate the effects that a single stress factor has on an organism. Researchers at the Max Planck Institute for Evolutionary Biology in Plön and the Universities of Helsinki and Jyväskylä, Finland, have now investigated the question of how microorganisms behave when they are confronted with more than one stress factor. “We simulated natural environmental conditions in the lab and exposed bacteria to both predators and antibiotics. This allows us to estimate how likely it is to find evolution of resistance to antibiotics outdoors,” explains study leader Lutz Becks.