Thread 1 - Lifeboat Muster Point for TalkExiles

[Kucinghitam]

Gather here all ye refugees from the foundering ship of JTT, if ye be in need of "How the heck do I format my post?" "Why can't I edit my typos?" "What do those acronyms mean?" and most importantly, "Where is everybody that I used to know?"

Or just to chat randomly.

The thing with our energy usage is that because we use a back boiler for heating and hot water, and have no gas, it actually goes down in winter. It feels strange knowing that we can light the fire and be cosy this winter while others aren't turning the heating on. Even though our arrangements are a faff, I have a sort of survivor's guilt.

We're with Octopus, and have had 3 energy saving sessions so far - I got £3.40 from the first two - the 3rd was yesterday so we won't get the results yet. Another tonight - with Octopus it's usually an hour at about 5 or 6ish, se we just adjust dinner to afterwards.

We're with Octopus and haven't had anything from them. It's probably because I've halved our bill, since last year. We had a wood burner 18 months ago and boy, what a difference it's made.

The energy shift thing is interesting. I don’t think it’s reached Bulb yet. Maybe I should start doing my washing and charging the car peak time just in case! (Actually washing often does happen late afternoon and charging the car is a rarity these days.)

Similar here, although we've had our woodburner for much longer. When it gets really cold, we whack it on and bask in the heat like lizards. Or cats. Phoebe loves being a puddle of melted cat in front of the fire.

She’s so like my black tortie, Kuc!

I love woodburners, but I wish I'd got one before I found out how terrible they are for air quality. I would find it difficult to justify now, but am secretly hoping that our next house has one already, so I can use it sparingly.

I adore torties! They're so pretty with their splotchy patterns. And I love that they show, on the outside, what all female mammals are really like.

what all female mammals are really like

Interesting - what does this refer to as a matter of interest?

I have already posted this pic of my tortie sisters upthread but any excuse to post it again:

The one bottom left is a dog, btw, hard though she’s trying to look like a cat just about to be rewarded with Dreamies - which is what they’re all gazing at.

All of them look like very distinctive personalities.

Female mammals have 2 X chromosomes per cell. But cells are set up to work with 1 X chromosome (otherwise males would be in trouble).

So to avoid having an overload of all the things the genes on the X produce, 1 X chromosome in each cell is switched off.

The choice of which one is switched off is random. And it happens quite early in embryo development - when the embryo is small bundle of cells (from memory it may be around the 16 or 32 cell stage). Every cell that depends from those initial 32 (or however many it is) will have the same X switched of as its parent cell. But that may not be the same as the cell next to it, which could have decended from a different cell in the original bundle.

Where cats come in, is that some of the genes for fur colour (specifically the black and ginger ones) are on the X chromosome. So if a female cat has 1 'black' X and 1 'ginger' X all the parts of her body with black fur developed from a cell that had the 'ginger' X switched off, and all the ginger parts came from a cell that had the 'black' X switched off.

This is grossly oversimplified but:

In mammals, sex is chromosomally determined. Males have one X and one Y, females have 2 X chromosomes (this is because we are diploid: one copy of each chromosome inherited from our father and mother). So, if a female mammal were to express both X chromosomes, there would be double the amount of X chromosome gene products as in males.

If a female offspring expresses both X chromosomes, there will be twice as many X chromosome gene products as in males. So there has to be a mechanism of dosage compensation to avoid overexpression. Early on in embryonic/fetal development, one of the X chromosomes in each cell is "silenced" - this is called X-chromosome inactivation and it sort of shrivels up into a Barr body (these are visible in the cell nucleus).

In a tortoiseshell cat, she inherits two versions (alleles) of a fur colour gene which is located on the X chromosome; suffice to say that one allele instructs orange fur and the other black fur. Because X-chromosome inactivation is random, this results in the patchy black-and-orange patterning. (The exact pattern depends on the timing of the inactivation during embryo development).

And so - all female mammals are invisibly tortoiseshell all over (with respect to alleles of genes on their X chromosomes).

Male tortoiseshell cats can exist, in the very rare condition of XXY males (like Klinefelter's Syndrome in humans).

Hah! Crossed with the other biologist!

You managed both more long words and fewer typos, so you win that round.

Some remarkable shitehoggery apparent when I looked into JtT today. I don't know why this should upset me, but it does. Old names, and even faces from meets, just being pillocks.

I love the genetics of cat colours. So much early embryonic development made visible. I wish there were a job that would pay me to just explain that to people all day.

Bonus fact: blue-eyed, white, deaf cats happen because of an error in a single cell in the very earliest stages of development (even before coat colour switches are applied). That single cell is the one that would normally go on to create all the melanin producing cells in the coat and eyes (hence the blue eyes and white fur). And it also forms the bones of the inner ear - so without it the cat is deaf.

@deeangelico Ooh, you've prompted me to think of a festive username! I'll have to ponder for a bit.

How's this? <twirls>

Aren’t almost all ginger cats male?

My cat is 100% British shorthair from a line of GCCF champions, but he has some swirly tabby-like patterns that appear in his summer coat. I think I remember reading somewhere that all British shorthairs are tabby underneath, or something like that.

Yes, but female ginger cats do exist.

@MavisMcMinty I forgot to say earlier, your cats are absolutely gorgeous!

Very sparkly indeed, Kuc!