This week’s Sunday Science covers vaccine and gene therapy successes, hearing loss, zombie (or not) pig brains, mysterious deep sea fish, and a new fossil human relative…

Over a billion people worldwide are living with some degree of hearing loss, about half of which is sufficient to cause at least moderate disability. One of the most common causes of hearing loss is actually aging; we all naturally lose some hearing ability as we get older, particularly at higher frequencies, as sensory hair cells die off, but there is a strong genetic component to whether this hearing loss becomes disabling or not. By the age of 65, 1 in 3 older people will have significant hearing loss, the second most common disability of aging, after arthritis. So there’s a real need to identify the underlying genetic causes, which are virtually unknown. An extensive genetic screen in mice has now uncovered an impressive 38 new genes involved in hearing loss. This should open up plentiful new research directions for future treatments. The original study is here (open access).

Today’s public service announcement: get vaccinated. Firstly, there is news that, globally, 170 million children under 10 are not vaccinated against measles. This includes a staggering 2.5 million children in the US and half a million in the UK: those figures, for two of the richest countries in the world, should be closer to zerothe exceptions being those children who are too ill or too young to be vaccinated. Measles kills. Vaccines are are safe and they work. And, in other news, a recent vaccine against HPV, which causes cervical cancer, has reduced pre-cancer cases by a very impressive 88% in Scotland – including amongst those who haven’t had the vaccine. (This is because less of the virus is being transmitted). Did I say get vaccinated? Get vaccinated, and vaccinate your children.

From established medical technology to the brand new: gene therapy has restored functioning immune systems to children with Severe Combined Immunodeficiency (SCID). This is a mutation that results in a total failure of the immune system to develop – meaning children with this disease invariably die of infections very young. Keeping them isolated in a completely sterile environment is the only option and is obviously problematic, unless they can receive a bone marrow transplant (from which immune cells grow). The disease has been a target of gene therapy attempts for many years, without great success, but this new study seems to be a real step forward in allowing these children to recover and live normal lives: so far seven toddlers are happily and healthily living at home. The original study is published here (rather technical, and paywalled).

When I was a child I went through a phase of being fascinated by the deep sea and all the weird and wonderful animals that live there. I haven’t entirely grown out of it. One of those weird and wonderful animals is a new species of deep sea snailfish, which lives in the Mariana Trench. This natural trench in the ocean reaches depths of 10km in places – resulting in immense pressures. How do animals survive this without being completely crushed? A fascinating study has thoroughly documented both the anatomy and the entire genome of the deep sea snailfish. For one thing, it has a partially open skull to stop it’s brain being squished out (yes really – see featured image). The genome has revealed a mutation in the gene responsible for mineralisation of the skeleton, meaning that it has soft bones, and interesting changes altering the stability and fluidity of its cell membranes. A lovely interlinking of anatomy and genetics with environmental adaptation, the original study can be found here (open access).

The fossil remains of a new species of human have been found in the Philippines, living as recently as 50,000-67,000 years ago. Homo luzonensis lived on the island of Luzon, and must have been alive at the same time as several other hominins  including our own species Homo sapiens, Neanderthals, Denisovans and Homo floresiensis. This last species is the infamous “hobbit” species that has thrown a spanner into the works of what we know about human evolution and migration around the globe. H. luzonensis was similarly small in stature, with a strange mixture of jaw adaptations and curved toe bones suggesting it climbed. The linked news and views article articulates these confusions nicely: our view of hominid evolution is becoming ever more complicated and fascinating. The original study may be found here (paywalled).

I wanted to mention this study, because it’s got a lot of frankly hysterical attention that I’m rather mystified about. Yes, it’s the zombie pig brains. Or “Pig brains revived after death!” as even Nature put it. Researchers took brains from pigs that had been slaughtered for meat and got them to do some interesting things. The study and opinion pieces have been careful to state that they didn’t revive actual brain activity (no electrical activity; no thought processes) but this doesn’t seem to have stopped people getting over-excited about it. In brief, what they did achieve was to keep the cells in the brains alive for up to 36 hours: those cells could perform basic cellular functions such as metabolising nutrients and getting rid of waste, and maintaining their structure. Some neurons were able to carry electrical signals in tissue samples from the brains. The blood substitute the researchers used to keep the brains “alive” did contain chemicals to inhibit electrical activity, as an ethical step to avoid the possibility of the dead animal brains regaining awareness, but it’s clear from the study that there was no possibility of this happening. As an organ, the brain was dead and not capable of performing any kind of coordinated function for the normal brain jobs, like receiving sensory input, controlling the body, or thinking. What this study is potentially useful for is that it says that you can get useful cellular and tissue samples out of brains that have been dead for a (relatively) long time and do studies on them. No zombies, sorry. The original study is here (paywalled).

And finally, here are the striking images that won in Nature’s Scientist at Work photo competition.

Featured image

Morphometric scans of the whole skeleton of the deep sea snailfish using micro-computed tomography. Taken from figure 3, Wang et al, Nature Ecology & Evolution volume 3, pages 823–833 (2019).



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