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Cake day: August 4th, 2023

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  • This is true for only red and green loght detecting proteins (opsins) - the blue opsin gene is on chromosome 7.

    The red and green detecting proteins have an interesting history in humans.

    Fish, amphibians, lizards and birds have 4 different opsins: for red, green, yellow and blue colours. And the blue opsin sees up into the ultra-violet. Most animals can see waaaay more colours in the world than we (or any mammal) can. So what happened that makes mammal vision so poor?

    It’s thought that all mammals descend from one or a few species of nocturnal mammal that survived the catastrophe that wiped out the dinosaurs at the end of the Cretaceous. The colour detecting cells (the cones) need a lot of light compared to ones that see in black-and-white (the rods) and therefore nocturnal animals frequently lose cones in favour of the more sensitive rods for better night vision. The mammals that survived the Cretaceous extinction had also lost the green and yellow opsins while keeping red and blue - basically the two different ends of the light spectrum.

    Consequently today most mammals still have only 2 opsins so your cat or dog is red-green colourblind.

    Why do humans see green? Probably because our monkey forebears, who lived in trees and ate leaves, needed to distinguish red leaves and red fruit (visible to birds) from the green background.

    But how did we bring back the green opsin? A whole section of the X chromosome (where the red opsin is coded) got duplicated in a dna copying mistake and then there were two genes for red opsins. As there are different alleles (versions), they could be selected for independently and so one red opsin drifted up the spectrum to be specific for green. So our green opsin is a completely different gene to the green opsin in fish, birds, etc. This kind of evolution happens a lot which is why, for example, there are many families of similar hormones like testosterone and estrogen. And steroids too.




  • All junior devs should read OCs comment and really think about this.

    The issue is whether is_number() is performing a semantic language matter or checking whether the text input can be converted by the program to a number type.

    The former case - the semantic language test - is useful for chat based interactions, analysis of text (and ancient text - I love the cuneiform btw) and similar. In this mode, some applications don’t even have to be able to convert the text into eg binary (a ‘gazillion’ of something is quantifying it, but vaguely)

    The latter case (validating input) is useful where the input is controlled and users are supposed to enter numbers using a limited part of a standard keyboard. Clay tablets and triangular sticks are strictly excluded from this interface.

    Another example might be is_address(). Which of these are addresses? ‘10 Downing Street, London’, ‘193.168.1.1’, ‘Gettysberg’, ‘Sir/Madam’.

    To me this highlights that code is a lot less reusable between different projects/apps than it at first appears.






  • That was one of the original proposed mechanisms to explain how the (obviously false) autism was caused.

    But since then, since thiomersal was removed, other ‘causes’ and moral issues have been invented, including cells from abortions.

    The one that makes me laugh the most is that it’s terrible that the poor poor baby is exposed to so many illnesses (measles, mumps, rubella, polio, tetanus, notovirus, rotovirus and more) in such a short space of time, it’s no wonder the poor dear’s immune system is compromised. And then the same mother drops the kid off at daycare and exposes the poor dear to all those viruses and more - and live viruses at that.

    There is no bleeding logic, just feels. And they get so angry at the fake harm that medicine is causing, and simultaneously actually causing real harms to real people.





  • Sorry for taking a long time to reply.

    with plain old binary fission cell division, how do you get both to divide at the same time, and give each cell one of the new organelles?

    An excellent question! Luckily it was answered in the paper. The researchers actually had a high resolution soft x-ray movie of cell division (ok, an exaggeration, they had a few micrographs showing the sequence). In the sequence, it showed how the organelles (including the novel N2 fixation one) undergoing division and each ‘child’ organelle ending up in different halves.

    Cell division is controlled in the cell by an amazing process:

    • 2 centres are created on opposite sides of the cell
    • Structures like tethers are built that connect each centre to each of the organelles (the nucleus, mitochondria and the N2 fixators). These are called microtubules
    • The microtubules then start shortening, pulling the organelles in two directions, separating them.

    The x-ray micrographs show that the N2 fixators are already integrated into this mitosis mechanism - my guess is that the N2 fixators already ‘understand’ the parent cell’s mitosis signaling.

    The authors also say that the organelles have lost a number of genes for essential cellular functions, relying on the parent cell to provide those capabilities. By comparison, mitochondria have only 37 genes left, and chloroplasts weren’t known for having any DNA when I was at school, but are now known to have about 110 genes.

    In other words, a lot of evolution has already occurred and they are well on the way to being ‘proper’ organelles.




  • As I was discussing this with my partner we summarised this as:

    Humans have always had the capacity for violence and murder; as populations grew, acts of violence could be larger, both in terms of number of combatants and also length of time of continuous fighting. This is a progression of:

    • Small bands of people skirmishing with neighbours to
    • Towns sending small raiding bands to
    • Cities fielding an army for a summer campaign to
    • Empires furnishing professional armies and sending them on multi-year campaigns, to
    • Nation states using advanced logistics to maintain millions of soldiers in the field for years at a time.

    Somewhere between city-states and full modern nation states, there have been full on campaigns of genocide. But genocide can be thought here definitionally as only possible with some significant number of people.

    Unfortunately there is a deep dark part of the human psyche that has always been with us.


  • I hear what you’re saying, but there’s a counterpoint to this.

    In prehistoric times, population densities were low. In mesolithic times (hunter gatherers) there were simply no concentration of people large enough to wipe out or to do the killing. Nothing could be called genocide at this time.

    In neolithic times (the first farmers) violence was definitely a part of life. Some early towns do show signs that they were destroyed. But again, population densities are low enough that the scale of violence would not be enough to call ‘genocide’. It’s a town burnt down with everyone murdered, not a ‘people’ - whatever that might mean at this time. This is not about egalitarianism - it’s population density.

    However as we move to the bronze age, there are definitely signs that large scale events occur that might fit into the modern concept of genocide but archeological evidence is severely lacking. The main line I would argue is that the male lines of the neolithic farmers in Europe are hammered and almost completely replaced with the Yamnaya Y chromosomes across a huge expanse - from the east european plains to the Iberian peninsula. Genetic continuity with the neolithic farmers is maintained though indicating that male newcomers were having children with local women, and very few male locals had children. During this event the culture changed hugely - burial patterns, material goods, etc.

    I don’t know if we can call this genocide - at least the full modern concept - because these changes took centuries to roll out across the expanse of Europe, but they speak to local conquests and, at the very least, the newcomers prevented local males from having their own families. At worst you can imagine a constant expansion of this new culture taking control of new areas, killing the men, taking local women as concubines and eradicating their gods, customs and ways of living. Quite a lot of genocidal checklist items ticked off there.

    By the mid to later bronze age, genicide is definitely a widespread thing, recorded in many texts.