You may have heard we’ve got this satanic feline padding about the house now, getting into mischief — she has discovered my collection of cephalopodiana, and her favorite toy is one of my stuffed octopuses that she wrestles and bats around the floor. It’s like she’s rubbing it in.
Anyway, a new paper in Nature Communications describes a comparative analysis of the genomes of tigers, lions, snow leopards, and…housecats. I’m not letting her read it, lest she acquire delusions of grandeur (oh, wait, she’s a cat — she already has that.)
There’s nothing too surprising in the data; as usual, we discover that mammals (well, animals, actually) have a solid core of shared genes and the divergence between species is accounted for by changes in a small number of genes. They also exhibit a high degree of synteny — the arrangement of genes on chromosomes are similar.
(a) Orthologous gene clusters in mammalian species. The Venn diagram shows the number of unique and shared gene families among seven mammalian genomes. (b) Gene expansion or contraction in the tiger genome. Numbers designate the number of gene families that have expanded (green, +) and contracted (red, −) after the split from the common ancestor. The most recent common ancestor (MRCA) has 17,841 gene families. The time lines indicate divergence times among the species.
But note the cladogram on the right, and this bit of information we must keep from the cats.
The tiger genome sequence shows 95.6% similarity to the domestic cat from which it diverged approximately 10.8 million years ago (MYA); human and gorilla have 94.8% similarity and diverged around 8.8 MYA.
The difference between a housecat and a tiger is a mere ten million years. If only they knew…
I plan to allow this cat to continue to play with my cephalopods. Distraction, you know.
Cho YS, Hu L, Hou H, Lee H, Xu J, Kwon S, Oh S, Kim H-M, Jho S, Kim S, Shin Y-A,Kim BC, Kim H, Kim C-u, Luo SJ, Johnson WE,Koepfli K-P, Schmidt-Küntzel A, Turner JA, Marker L et al. (2013) The tiger genome and comparative analysis with lion and snow leopard genomes. Nature Communications 4, Article number: 2433 doi:10.1038/ncomms3433
The way in which you make fun of cats is very similar to the way in which Galaxy Quest makes fun of Trekkies. Satanic, indeed.
The fat cat on the mat
may seem to dream
of nice mice that suffice
for him, or cream;
but he free, maybe,
walks in thought
unbowed, proud, where loud
roared and fought
his kin, lean and slim,
or deep in den
in the East feasted on beasts
and tender men.
The giant lion with iron
claw in paw,
and huge ruthless tooth
in gory jaw;
the pard*, dark-starred,
fleet upon feet,
that oft soft from aloft
leaps on his meat
where woods loom in gloom–
far now they be,
fierce and free,
and tamed is he;
but fat cat on the mat
kept as a pet,
he does not forget.
— “Cat” by J. R. R. Tolkein
* pard – an archaic term for leopard.
Don’t let cats know that they are related to tigers? Hell, cats think they ARE tigers.
Oh, PZ, that finagling feline has outfoxed you. You think this was your idea:
It was not. That cat cleverly co-opted your consciousness, sneakily slipping in that article for you to read while blasting your brain with it’s mind control rays.
There is only one solution: you must immediately don your aluminum foil hat and go at least 5 miles from the controlling cat. Post photos to this blog so that we can see you made it out.
Awww the kitty loves you and wants to get your scent.
I think I now understand just why my cat looks at me the way he does. Notice that I am more closely related to a mouse than to any of the carnivora.
Squeeeeek!
It’s not a delusion.
Interesting that the cat diverged earlier, yet maintains more similarity. Or is that difference just not statistically significant?
Thanks for posting this. It is a good day when you can learn something new,
& before today I had no idea that Venn diagrams came in varieties other than
the three circles you see in logical demonstrations. Where the cat is concerned,
you’re on your own.
Pix or it didn’t happen.
– he typed with his left hand because a big fuzzball slept on his right.
Well, not quite. Unlike lots of dogs, they actually know they’re not big enough to kill you. (Which is why they don’t bother trying.)
It probably isn’t. However, rates of evolution aren’t static. That’s probably why the older ages in the tree are so far off (“58” is suspicious, “90” should be at most 65, “101” probably too, and “132” should be more like 160).
I have a female black feline. She loooooves beards. Protect your beard and nearby vulnerable bits from outstretched paws and claws and butting heads—her aim might be off.
Cats just diverge, period.
@2, Gregory: Thank you for that. I hate poetry in general* but that’s my all time favorite. I memorized when I was in college MANY years ago and still know it.
*Perhaps that’s not quite true. I quite enjoy Cuttlefishe’s verse. (Doggerel?) Maybe I should just say I hate the kind of poetry they made me read in High School. Take “Trees”, by Joyce Kilmer. Please.
Delusion.
Oh sure, your cat acts all mean and tough towards a stuffed octopus on the floor, but we know the reason cats avoid water is that it is inhabited by cephalopods.
Whenever I see these comparisons of genomic similarity/differences, I am always puzzled why no distinction is made between active expressed genes and “junk” DNA. Surely to prevent comparing apples to pears, we should primarily compare active genes. Given 94.8% similarity between humans and gorillas, how much of that lies in the “junk” DNA? If there was a 20% difference in active DNA, but the active range is relatively small (which I understand it is) then surely that large difference would be masked by the similarity in the junk DNA.
I would also expect less divergence in the junk DNA since there is less selection pressure for change in that range.
Please excuse my lack of correct terminology, biology is not my field of study. I have tried to research this angle, but my lack of knowledge of the field leads me down blind alleys. I appreciate any pointers in the right direction.
Oh, they know, that’s why they pulled the cute meowing con:
The tigers are a nearly extinct species while the housecats species numbers over 200 million individuals. The Most Perfidious Feline are prospering by parasiting the human race, like the wicked little aristocrats they are.
A cat’s perception of its size is very flexible. Ours wasn’t afraid of our German Shepherd, so in her mind she was as big as a Shepherd. And since she knew she was most other cats agreed.
So, you’re saying it took cats 2 million years to start training primates?
But when did cats and demons diverge?
I don’t believe they have.
@Licorice allsort #12:
*arms nuke*
@Peter Brand @18
For this part, it’s actually the other way around. Since there is no selection pressure to maintain the junk (errors are more tolerated), it tends to diverge much more quickly. Furthermore, a lot of the changes involved in domestication involve neoteny which is more of a change in gene regulation than function. Incidentally, that’s also the reason humans look like baby chimps.
Yvonne Rathbone @21 – nah, but they probably found us slow on the uptake.
My favourite cat poem: Hamlet’s Cat’s Soliloquy, by Shakespeare’s Cat.
To go outside, and there perchance to stay
Or to remain within: that is the question:
Whether ’tis better for a cat to suffer
The cuffs and buffets of inclement weather
That Nature rains on those who roam abroad,
Or take a nap upon a scrap of carpet,
And so by dozing melt the solid hours
That clog the clock’s bright gears with sullen time
And stall the dinner bell.
To sit, to stare
Outdoors, and by a stare to seem to state
A wish to venture forth without delay,
Then when the portal’s opened up, to stand
As if transfixed by doubt.
To prowl; to sleep;
To choose not knowing when we may once more
Our readmittance gain: aye, there’s the hairball;
For if a paw were shaped to turn a knob,
Or work a lock or slip a window-catch,
And going out and coming in were made
As simple as the breaking of a bowl,
What cat would bear the household’s petty plagues,
The cook’s well-practiced kicks, the butler’s broom,
The infant’s careless pokes, the tickled ears,
The trampled tail, and all the daily shocks
That fur is heir to, when, of his own free will,
He might his exodus or entrance make
With a mere mitten?
Who would spaniels fear,
Or strays trespassing from a neighbor’s yard,
But that the dread of our unheeded cries
And scratches at a barricaded door
No claw can open up, dispels our nerve
And makes us rather bear our humans’ faults
Than run away to unguessed miseries?
Thus caution doth make house cats of us all;
And thus the bristling hair of resolution
Is softened up with the pale brush of thought,
And since our choices hinge on weighty things,
We pause upon the threshold of decision.
– Henry Beard
I had remembered this quote as coming from Heinlein, but apparently not:
“In ancient times cats were worshipped as gods; they have not forgotten this”. ~ Terry Pratchett
Cats are very similar to many humans. Each is the center of their own universe, some more than others. They preen, squabble, share, and love. They can be pissy, needy, or aloof. Perhaps that is why we love them so. They are us, with fur.
Some of us may know of Robert Blake’s famous poem “The Tyger” (1794):
Tyger Tyger, burning bright,
In the forests of the night;
What immortal hand or eye,
Could frame thy fearful symmetry?
–
But we now have the answer: a tiger is more-or-less an overgrown domestic cat. If tigers aren’t fearsome enough, they got exaggerated into a legendary monster, the manticore.
–
Tigers are now very vulnerable; they’ve met their match in one of their victims.
Ipetrich, never heard of Robert, surely you mean William Blake?!
I squeed. It’s awesome.