Thursday, May 11, 2006


“How can the two of them be “womb-mates” and so different?”
They probably have different fathers, even though they are littermates. More than one male can mate with a female when she is in heat, and all the resulting kittens are born at once. Happens all the time.

Well, some smart aleck anonymous (A. Nonny Mouse?) commentor just blew the mystery that I was going to begin with for this section of Cat Stuff, so I’ll just go with it. These two kittens were “womb-mates,” I was assured, and the mother was what I call a “pastel calico.” (Don’t listen, vet assistants!) That is, she was tri-colored, but they were all pale colors. Tri-colored is good because it means there are two X-genes so there is extra information. I wanted short haired cats but she had a kind of double-coat, some long and then an underfur. Of the two kittens, the tortie has short plushy downy fur and the yellow ombré (I really like that word -- maybe I should have named these two “Ombré” and “Penumbra.” Naw. Too pretentious for Valier cats.) has fur more like hair, flat.

What I don’t know is how many “baggies” they came in. That is, the birth sacs. One for each? Or two in one bag? The mother cat was elderly and I suspect that there were other ova that simply didn’t get fertilized or that were too old to develop properly so were resorbed. It is, as Commentator points out, quite common for cats to have several fathers in one brood of kittens -- or so it is thought. I don’t know who did the DNA analyses that proved this.

But it’s accepted as fact that cats ovulate at the time of mating and they have been observed repeatedly mating. I have a notion, however, that this cat was NOT supposed to mate and only escaped outside once, but I base that on the extremely orderly and controlling human mother. The question is, why didn’t such a careful planner get the cat spayed? The confusion of a collapsing marriage? (A divorce had been begun.)

Close molecular comparison of DNA has been a revelation. We’ve discovered how many animals that were supposed to mate for life actually fool around on the side a bit. We’ve discovered that while Tarzan of the Chimps was out pounding his chest and swashing branches around, his fav girl-friend Tillie was doin’ it behind his back with some poetic anthropoid.

More amazing than that (I mean, what reasonably experienced person expected something different?) is the discovery that some people are two people. If twins begin to develop, but something stops one from growing at an early stage, it can be built into the surviving twin, so that one woman had one kind of DNA in this organ and another kind (her potential but nonexistent sister’s) in that organ. One boy was born seemingly normal, later became “pregnant” because his scrambled-up potential sibling, who early-on didn’t keep developing, appeared (still scrambled) during his adolescence as a cyst in his abdomen. And they say that women who carry and give birth to children might have cells from those children wandering around in their bodies for many years afterwards.

I read once that there are some basic structural advantages for predators so successful that they evolve over and over in mammal, reptile, dinosaur, or whatever. The eyes need to be big, right up front, sensitive enough to see in the dark; the short nose and big ears need to be equally sensitive and up on the front of the skull like the camera at the tip of the laparascope that pushes the sensors through the tunnel. Long bodies, springy legs, clingy clawed paws. Weasels, ferrets, lizards and so on. It is very hard to get much variation in the genome of a cat -- it either works like this or it gets aborted. Even the gene that causes a short tail in a Manx can only be single -- if it’s on both sides of the double helix, the cat will be born with an open spine and will not survive.

The often-ignored side of cat breeds is that the in-breeding necessary to achieve a certain look means that those cats will be much more vulnerable to genetic mutations, mismatches, and diseases. It takes a certain kind of emotional grit to create a high percentage of doomed kittens in order to have, say, a flat-nosed, short-furred cat with a particular coloration -- or a bald cat (ugh). Of course, it takes a certain amount of grit to allow a cat to get pregnant over and over without any plan for the kittens beyond giving them away to strangers or abandoning them somewhere. (People have the idea that Valier is a good place to leave kittens that aren’t cute anymore.) Of course, if your cats are out in the country, the local predators (including the farm machinery) will probably take care of them. But a certain kind of urban person insists that all cats live indoors at all times.

When I google , I get 1,650 hits. One person talks about the need for a framework of “marker” genes and then a “dense map.” Another is mixing genes from domestic cats with various species of wild cats. I’ve seen a few of these crosses. It’s great when they have a housecat disposition with a big burly body instead of the other way around. Here’s the stuff one seminar discussed for the sake of breeders who were having problems: fading kitten syndrome and neonatal isoerythrolysis; molecular genetic tests; feline hereditary coagulopathies; the feline genome project; heritable characteristics, phenotypic expression and natural history of hypertrophic cardiomyopathy in Maine Coon Cats; hereditary eye diseases; lysosomal storage diseases in cats; patellar luxation and hip dysplasia in cats; heritability of susceptibility to infectious disease; polycystic kidney disease in Persian cats; development strategies for DNA-based tests for cat parentage verification. You’ve got to have grit to face all this stuff.

Of course, if you just lower your resistance and let a cat choose you, you’ll probably acquire a survivor. Which is something to consider when you know that scientists say that the genes of a cat, which are only molecules of proteins after all, are often found in humans as well. We’re all mammals and share that formula, but more than that, viruses carry gene molecules back and forth, especially if your cat -- like mine -- sleeps under your chin.

So now the cat is out of the bag: what about West Nile Virus which kills horses and cats?? What about the bird flu which is said to kill cats? What about those Germans who, on hearing this, immediately disposed of their cats? You’ve got to have grit. Cats aren’t for pussies.

1 comment:

I LUV CATS said...

I found the cutest photo on your site.