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Category: genetics

Circulating branched-chain amino acids (BCAAs) are elevated in obesity and diabetes, and recent studies support a causal role for BCAAs in insulin resistance and defective glycemic control. The physiological mechanisms underlying BCAA regulation are poorly understood. Here we show that insulin signaling in the mediobasal hypothalamus (MBH) of rats is mandatory for lowering plasma BCAAs, most probably by inducing hepatic BCAA catabolism. Insulin receptor deletion only in agouti-related protein (AgRP)–expressing neurons (AgRP neurons) in the MBH impaired hepatic BCAA breakdown and suppression of plasma BCAAs during hyperinsulinemic clamps in mice. In support of this, chemogenetic stimulation of AgRP neurons in the absence of food significantly raised plasma BCAAs and impaired hepatic BCAA degradation.

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SARS-CoV-2 mutations similar to those in the B1.1.7 UK variant could arise in cases of chronic infection, where treatment over an extended period can provide the virus multiple opportunities to evolve, say scientists.

Writing in Nature, a team led by Cambridge researchers report how they were able to observe SARS-CoV-2 mutating in the case of an immunocompromised patient treated with convalescent plasma. In particular, they saw the emergence of a key mutation also seen in the new variant that led to the UK being forced once again into strict lockdown, though there is no suggestion that the variant originated from this patient.

Using a synthetic version of the virus Spike protein created in the lab, the team showed that specific changes to its genetic code — the mutation seen in the B1.1.7 variant — made the virus twice as infectious on cells as the more common strain.

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Analysis reveals genetic control elements that are linked to hundreds of human traits.

Twenty years ago this month, the first draft of the human genome was publicly released. One of the major surprises that came from that project was the revelation that only 1.5 percent of the human genome consists of protein-coding genes.

Over the past two decades, it has become apparent that those noncoding stretches of DNA, originally thought to be “junk DNA,” play critical roles in development and gene regulation. In a new study published on February 32021, a team of researchers from MIT has published the most comprehensive map yet of this noncoding DNA.

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Sperm are ‘ruthless competitors’ who aren’t above poisoning their brothers.

Mouse sperm carrying a genetic sequence called the t-haplotype will poison their competitors, then make an ‘antidote’ only for themselves, new research finds.

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Many believe that drug companies should already be updating their vaccines to target mutated versions of the Covid-19 spike protein. But can the patterns of mutations scientists are seeing popping up in Covid-19 around the world offer any clues about how the virus will continue to evolve?

“It is hard to speculate, but it is interesting that all of a sudden there does seem to be a lot of mutations appearing that could be associated with immune escape or immune recognition,” says Brendan Larsen, a PhD student working with Worobey in Arizona. He recently identified a new variant of Covid-19 circulating in Arizona that has the H69/V70 deletion seen in several other versions of the virus. While still only spreading at a relatively low level there and in other states of the US, it suggests that this particular mutation is recurring independently around the world.

Every time the coronavirus passes from person to person it picks up tiny changes to its genetic code, but scientists are starting to notice patterns in how the virus is mutating.

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