Friday, October 13, 2017

Pre-DNA Double-helix Genetics

Dominant and Recessive: Mendel's Peas
I don't know how many reading this had textbooks in which genetics were Mendelian.  I was an assistant professor before the brightly colored, full-paged Life magazine publication of the double helix appeared and was read by everyone.  When I was in school, Genetics was those three generations represented schematically in terms of genetic dominance.  We all realized that of four children of the same parents, the two brunettes also carried genes for red hair (and that was why ladies who wanted to be red-haired had only to bleach their hair with hydrogen peroxide), and the two kids who had been tow-haired as youngsters did not grow up red-haired (as my next sister and I did), but brown-haired.  Indeed, my father was true blond and my mother brunette.  But all four of us children had brown eyes.  I suppose that was why I found genetics interesting.  Both of my paternal grandparents had pale eyes, and and my father's were true pale gray, but so were my maternal grandfather's.  Nana's were a beautiful dark chocolate brown, and her lashes and brows were as black as her hair (and, of course, it turned white and black, real salt and pepper, as she aged).
Anyhow, if you want to know about Mendel, whom I regard as an intellectual hero, just go to the Wikipedia.  And yet, with all the Ancestry advertisements and Louis Gates on television, I haven't gone beyond popular genealogy.  And it would be genetics that would tempt me.
What I began thinking about was that Mendel, so far as he could go without technology, remains worth considering.  He was very careful, after all.  And it's not as if genetic dominance were hogwash.  I daresay the minor uncertainties that so worried early 20c scientists here and there in a Mendelian third generation could be explained, e.g., by epigenetic research—not that I'd know how to do it.
Note: When I faced all the pages of Egyptian painting provided in the Images by Google, though I did not find another cat between Dynasty 18 and the Late Periods, I did find one from the famous tomb of Khnumhotep of Dynaasty 12 (Middle Kingdom) at Beni Hasan, more than half a millennium even earlier than Nebamun's.  It is the same kind of cat and also, of course, is part of Khnumhotep's hunting scene.  Of course, Middle Kingdom painters didn't use modeling as a few New Kingdom ones did. But I went through all the tiresome choices of Egyptian painting for Middle School children and did not find additional cats. 
Back to living cats.  Cats do have eyelashes (to be distinguished from the furry rims in the place of brows), but they are hard to photograph.  One day a close-up of my ginger tabby, Percy, did record his lashes, and they are ginger-colored, too.  I conclude with photos taken the same day which seem to match the pattern of markings on Nebamun's cat.

Showing "red" lashes

When eyes are fully open, the lashes don't show
The sections of pattern are alike, down to the tail
The stomach markings have yet to be photographed...

I forgot to mention a couple of important details:
(l) The Egyptian ones I found are, so to speak, black-and-blond tabbies, and they are the ones that have identical markings, in exactly the same configurations and symmetrical.  Even as dark tabbies have black stripes they also have dark eyelashes, and so has Percy, my cat.  Yes, cats do have very slight lashes on their upper eyelids (not to be confused with the short hair brows, so to speak), and only the hybrid males with white bibs, bellies, and paws have the lashes that are pale.  I have never seen a blond tabby from Egypt.
(2) The new young "Morris", the blond one (like the original Morris, whether he was part white I no longer remember) on some of the bags of Nine-Lives kibble, with his "signature" written across him, is like Percy, identically marked, line for line, and with the same adorable face, with a little chin like that which now serves as the trademark of the New York Public Library.  Young "Morris" (the blond one: the same brand of cat food also used black-and-tan kittens).
(3) I cannot guess how many painted Egyptian cats there are.  Stupidly, I once supposed that all the bronze cats, which are feminine, of course, too, are the dark color of ancient bronze.  Well, I suppose they may have been.  I mean that I have been forced to admit that though the goddess Bastet ought to have been a brown goddess's color, she wasn't always so imagined.  I mean, the Louvre has a tiny bronze of a bronze mother cat happily nursing a litter of kittens, and perhaps she isn't even Bastet.  So far, I rely on the Cat Fanciers' page that says that it is only toms that are free of white patches.

It is astonishing how interesting things are once you quit just assuming.  Well, Darwin's curiosity was legendary.

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