wrizard's super basic guide to y-chromosome-based identification!!
for those interested, on this fitzcovery day:
a dear friend asked me to explain why i felt completely insane about the phrase "genetic distance of one" and, as usual, i got overexcited and wrote an entire thing about it complete with goofy images! it's on twt HERE, but i figured it would also be nice to pop it up here also. SO. with the caveat that it has been many years since my last bio class and this is VERY OVERSIMPLIFIED. here's
Human DNA is grouped into chromosomes. We generally have TWO of each chromosome: 22 pairs (numbered 1-22), plus one pair of sex chromosome (typically either two X-chromosomes (XX), or one X-chromosome and one Y-chromosome (XY)). That's 23 pairs, or 46 chromosomes, in total.
When producing sex cells, matching chromosome pairs will RECOMBINE (swap bits of information) - eg. one Chromosome 4 will remix itself with the other Chromosome 4, making TWO UNIQUE C4s. When the cell splits into two sex cells, each sex cell will carry ONE unique C4.
That's sexual reproduction! Every new offspring is genetically unique - new combinations of traits pop up quickly, and if they improve reproductive fitness, can be passed on to future offspring. This allows for rapid adaptation and changes in a species over time.
But what about Y-chromosomes, which don’t have pairs? They can't recombine in the way paired chromosomes can - which means Y-chromosomes pretty much only change via mutation (errors in copying DNA). Mutation is VERY slow, especially compared to recombination.
This means that when an XY parent passes down their Y-chromosome to a child, chances are high that chromosome will have few, if any, changes – as opposed to X-chromosomes, which recombine in both XX parents and children, shuffling genetic information all over the place.
Due to this slow rate of change, Y-chromosomes can be more easily tracked through the generations than other human chromosomes. A Y-chromosome might be passed down nearly unchanged for hundreds of years from genetic father to genetic son.
GENETIC DISTANCE refers to the measurement of difference between two sets of DNA. The lower the genetic distance, the more closely related the two samples are likely to be. A genetic distance of 1 means the samples are close to identical.
Because we know how slowly Y-chromosomes change over time, we know that if the Y-chromosomes of two people have a low genetic distance, this implies that those people are paternally related – even if the two people live/lived hundreds of years apart.
In the case of Captain James Fitzjames, genetic data was extracted from a set of unidentified remains (a molar from a disarticulated mandible). 17 genetic markers from the molar’s Y-chromosome were compared to the Y-chromosome of a confirmed paternal relative of the Captain.
Those 17 markers were the same in both samples, giving the two Y-chromosomes a genetic distance of one – meaning, with the genetic information available, the living relative and the unidentified decedent are more than 2000 TIMES more likely to be paternally related than not.
EDIT: DOIP I MISREAD THE CHART 16 of 17 match, not all 17!!
Along with all the information we have from the historical record, the context of the remains, and this new comparative genetic analysis, we can safely conclude that this particular set of remains belong to Captain Fitzjames.
160 years isn't long in the grand scheme. Every identified set of remains is another reminder that these were people, not just a distant curiosity. It's humbling to remember not just that we have identified Cpt. Fitzjames, but that still, today, we have a genetic distance of one.
Photos and Y-chromosome comparison chart taken from Stephen, Fratpietro, and Park's paper "Identification of a senior officer from Sir John Franklin’s Northwest Passage expedition" from the Journal of Archaeological Science: https://www.sciencedirect.com/science/article/pii/S2352409X24003766?via%3Dihub
hope my nonsense is helpful and/or informative and/or at least made you smile!! if you like this sort of thing :) cheers doves
I'll be your medicine, if you let me
Give you reason to get out of bed
Sister I'm trying to hold off the lightning
And help you escape from your head
(holly humberstone -- deep end)
can't think about animorphs without thinking of the girls (agony). finally found my box of the novels i've been missing for years and i missed them SO bad. if i'd known about shipping when i read them the first time... good lord. that is a fucked up horrible polycule and i don't even need them to kiss i just need them to HUG EACH OTHER YKNOW.
daemon au: jfj and rosalinda, the long-tailed weasel, in an official daguerreotype. she's in her nicest most professional navy blue bow and fussed for AGES about the best position to be in, and fixed jfj's hair roughly eight hundred times. i like to imagine this is when they got promoted pre-canon
(also on twt here xo)
some more thoughts about dear rosalinda and choice of Creature under the cut:
this is an elaboration of specific thoughts i have re: how settling/forms would likely work in a fun fantasy victorian daemon au, specifically that it would ABSOLUTELY be HUGELY unusual for anyone to settle as a species that would be Weird to see in their usual environment/where they grew up -- jfj gets to have a Special ~Exotic~ Species specifically because of the CONNOTATIONS!!
long-tailed weasels are not native to the british isles!! they're from the americas, from the far north through to parts of brazil. they LOOK essentially like british weasels, but twice the size and with a tail 2-3 times as long.
so, from a distance, rosalinda looks like a "normal" male weasel with a strange tail, which isn't too unusual -- a soul and a body sharing one sex isn't much to remark on in these scientifically enlightened times -- but when one hears her voice, it's easy to tell she's a female twice the size of any other she's ever met.
she utterly hates when people assume she's a boy, and will protest at length (in private); her interest in fine ribbons and bows is as much an attempt to shout her sex as it is a genuine passion. she is very sweet and curious, if a bit fiery and quick to judge.
gender AND ethnicity in MY jfj soup??? more likely than you'd etc.
billy gibson patron saint of guys just trying to pay the rent and guys whose hell-situationships-slash-exes have suddenly brought home a farm animal which may or may not have been stolen from a local petting zoo event
[also on twt here]
full text messages under the cut lmao
no i did not bother to actually look up a passage. yes jirving asked ned, who is actually bisexual, and both immediately understood john was talking about billy and drastically misunderstood the situation
more terror daemon AU sketches i forgot to post until this second!! (also on twt here xo) our dear harry goodsir and his sweet cordelia, the little brown bat (yes, named after King Lear). she is very small and skittish and shy but will absolutely correct you if you're wrong. this can be socially uncomfortable because she is right like 95% of the time and Not polite about it
further bat doodle and MORE THOUGHTS under the cut
SOMEONE IS WRONG ON THE INTERNET HARRY. SOMEONE IS GOING ONLINE AND TELLING LIES
i love her so much. she is Annoying but extremely sweet and precious and small and quiet. she gets along very well with other daemons typically, and has wonderful bedside manner; she's VERY affectionate and will ride around on harry's head all day if allowed. she gets very sad when ppl are like "ew a bat" tho. she's friendly and sociable! it's hardly her fault people have strange ideas about the species she settled!
also people tend to forget that she's extremely quick and agile in the air, because she tends to scuttle about on the desk when people are around, or hang off of harry's glasses for a lark.
she will ride around on other daemons she gets along with, too, when she gets the chance -- she really likes graham gore's daemon (a dog??) and will cling onto her head and have a chat and a cuddle like that. she will Not approach the ship cats or Neptune due to being tiny and food-shaped and also they are Very Big. and neptune is so LOUD.
"who cares where the ring came from? it's ours, now, isn't it?"
as i have been gnawing on a terror daemon au of my own: billy gibson and camelia (a barred grass snake), discussing matters of the heart.
also on twt here xo
some more thoughts on bill and cam under the cut:
camelia is a bit more childish and petulant than billy but also a bit friendlier; she acts extremely polite in company, especially around smaller prey-shaped daemons, despite being well aware of exactly how much faster she is. and how easily she could swallow them.
she DOES NOT LIKE THE COLD and spends 90% of her time as a necklace or up billy's sleeve with just her head poking out, unless she's messing with armitage's squirrel or snuggling with jopson's cat* (they get along much better than their people). or cuddling hickey's sweet lil rat
(she and hickey's rat would maul each other for one corn chip but also they might be in love? it's confusing. camelia is less on guard with her than she should be, always certain that worst comes to worst, she's faster and bigger. she's not wrong, but she's not right, either)
*jop to me either has a big grey cat or a marten and i like both of these ideas SO MUCH. either way: shot smaller hawks than you line multiplied by a sweetheart creature who shouldn't look half so proper, staring at hickey's little rat, tipping her head (suddenly: a predator) and saying, "caught smaller mice, too :)"
