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Humans Might Be So Sickly Because We Evolved to Avoid a Single Devastating Disease:
Sialic acids are a diverse group of carbohydrates that blossom like leaves from the tips of proteins covering the surfaces of human cells.
[...] Changes in sialic acid markers can give rise to a number of diseases. But it was one specific change particular to all humans that the researchers here were most keen to gain an understanding of.
Most mammals – including closely related apes – have a compound called N-glycolylneuraminic acid, or Neu5Gc. We've known for some time that the gene for this version of sialic acid is broken in us, leaving its precursor form, N-acetylneuraminic acid (Neu5Ac), to do its job.
Researchers previously speculated that this mutation was selected for in humans to make it harder for devastating malarial parasites such as Plasmodium knowlesi to latch onto red blood cells.
[...] Since chimpanzees retain the gene for Neu5Gc, the mutation must have occurred within the past 6 million years or so, sometime after we parted ways from one another.
[...] This most recent study shows Neanderthals and Denisovans share our variant of sialic acid, meaning the change happened before our branch of the family tree separated roughly 400,000 to 800,000 years ago.
[...] To differentiate between cells that belong to us from possible invaders, our immune cells are armed with a scanning chemical called sialic acid-binding immunoglobulin-type lectins. Or Siglecs for short.
When an inspection occurs, if a cell's sialic acid marker isn't up to scratch, it's curtains for that cell. Naturally, any changes to our sialic acid name-tag would imply our system of Siglecs would have needed adjusting as well.
Sure enough, on further investigation the researchers found significant mutations among a cluster of Siglec genes that are common to humans and their ilk, but not great apes.
[...] Siglec expression is linked with conditions such as asthma and Alzheimer's disease, raising the possibility that protection from a devastating disease put us at risk of other conditions.
Journal Reference:
Naazneen Khan, Marc de Manuel, Stephane Peyregne, et al. Multiple Genomic Events Altering Hominin SIGLEC Biology and Innate Immunity Predated the Common Ancestor of Humans and Archaic Hominins [open], Genome Biology and Evolution (DOI: 10.1093/gbe/evaa125)
(Score: 4, Interesting) by meustrus on Monday August 10 2020, @03:10PM (3 children)
There was an interesting study I read last year that speaks to the effect of cleaning chemicals. It exposed baby animals to industrial solvents like sodium laureth sulfate which are often present in household cleaning products, even sometimes baby wipes, soaps, and lotions. Then it exposed them to common allergens like peanuts.
It found that the animals exposed to the solvents developed allergies to those allergens more frequently. Their theory is that these solvents break down the outermost protective barrier of the skin, and the infant immune system categorizes as dangerous whatever it sees getting past that missing barrier.
We need to realize that when there are billions of germs in our homes, killing 99.9% of them still leaves millions of germs. It's not possible to maintain a house with children like it's some kind of scientific clean room.
If you're going to be worried about disease, just follow the CDC's COVID guidelines - wipe down door handles and light switches with a mild detergent, and avoid sharing air with sick people. Clean wounds to avoid infection. Don't try in vain to sterilize your house. Plain water will clean most things; rubbing alcohol will disinfect and clean shiny surfaces without streaking; soap and detergent helps with greasy messes and germs, but not much else; peroxide dissolves organic substances like blood, feces, and dyes; vinegar+baking soda is cleaner and more powerful for difficult messes than any single home cleaning chemical you can buy. Never use bleach wipes. You're probably not using them right anyway - check the instructions.
If there isn't at least one reference or primary source, it's not +1 Informative. Maybe the underused +1 Interesting?
(Score: 0) by Anonymous Coward on Monday August 10 2020, @03:25PM
In the USofA, plain water will dissolve most things.
(Score: 0) by Anonymous Coward on Monday August 10 2020, @05:11PM (1 child)
The problem is people are trying to wash "dirt" away and the skin of kids is suffering. How many kids with patches of eczema all over their bodies? This didn't happen 100 years ago. Even 50 years ago. How many times did you see "dirty" kids walking around? And today? You are lucky to see them outside of their sterilized house.
Stop cleaning and start actually protecting kids. You know, lock away the chemicals and stop spraying your fucking laws with poison and let the kids get dirty. The 3 things consumerism + Dow Chemical (or J&J or P&G) ads certainly don't want you to do.
(Score: 0) by Anonymous Coward on Tuesday August 11 2020, @05:05AM
I have something dirty for them to play with - let me bring it outside...