Pseudogene discovered in cats - implications

[gallo]

A paper published in the PLoS Genetics journal tells of the discovery of a pseudogene in cats.

Pseudogenization of a Sweet-Receptor Gene Accounts for Cats' Indifference toward Sugar

Synopsis: Although sweet sugars are ubiquitous in human foods, they are seldom added to cat food, and owners usually do not feed sweets to their cats. This is because, in contrast to most other mammals, both domestic cats and their wild cousins, the big cats, do not show a preference for and, most likely, cannot detect sweet-tasting compounds. Other than this sweet blindness, the cat's sense of taste is normal. The molecular mechanism for this unique behavior towards sweets was not known, until now. Sweet compounds, including sugars and artificial sweeteners, are recognized by a special taste bud receptor composed of the products of two genes. The authors found that in cats, one of these genes is not functional and is not expressed. (It is called a pseudogene.) Because the sweet receptor cannot be formed, the cat cannot taste sweet stimuli. During the evolution of the cats' strictly carnivorous behavior, selection to maintain a functional receptor was apparently relaxed. This research provides a molecular explanation for the common observation that the cat lives in a different sensory world than the cat owner.

Abstract: Although domestic cats (Felis silvestris catus) possess an otherwise functional sense of taste, they, unlike most mammals, do not prefer and may be unable to detect the sweetness of sugars. One possible explanation for this behavior is that cats lack the sensory system to taste sugars and therefore are indifferent to them. Drawing on work in mice, demonstrating that alleles of sweet-receptor genes predict low sugar intake, we examined the possibility that genes involved in the initial transduction of sweet perception might account for the indifference to sweet-tasting foods by cats. We characterized the sweet-receptor genes of domestic cats as well as those of other members of the Felidae family of obligate carnivores, tiger and cheetah. Because the mammalian sweet-taste receptor is formed by the dimerization of two proteins (T1R2 and T1R3; gene symbols Tas1r2 and Tas1r3), we identified and sequenced both genes in the cat by screening a feline genomic BAC library and by performing PCR with degenerate primers on cat genomic DNA. Gene expression was assessed by RT-PCR of taste tissue, in situ hybridization, and immunohistochemistry. The cat Tas1r3 gene shows high sequence similarity with functional Tas1r3 genes of other species. Message from Tas1r3 was detected by RT-PCR of taste tissue. In situ hybridization and immunohistochemical studies demonstrate that Tas1r3 is expressed, as expected, in taste buds. However, the cat Tas1r2 gene shows a 247-base pair microdeletion in exon 3 and stop codons in exons 4 and 6. There was no evidence of detectable mRNA from cat Tas1r2 by RT-PCR or in situ hybridization, and no evidence of protein expression by immunohistochemistry. Tas1r2 in tiger and cheetah and in six healthy adult domestic cats all show the similar deletion and stop codons. We conclude that cat Tas1r3 is an apparently functional and expressed receptor but that cat Tas1r2 is an unexpressed pseudogene. A functional sweet-taste receptor heteromer cannot form, and thus the cat lacks the receptor likely necessary for detection of sweet stimuli. This molecular change was very likely an important event in the evolution of the cat's carnivorous behavior.

What do you think the implications of this research are for creationism and/or evolutionary biology, if any? This is certainly easily understandable from an evolutionary standpoint. As mentioned, cats are obligate carnivores, i.e., they must eat red meat or fowl or die. However, I fail to see how this finding could support the assertion by creationists that cats were once vegetarians that ate fruit.

[Starboy]

Quote by: gallo However, I fail to see how this finding could support the assertion by creationists that cats were once vegetarians that ate fruit.

If the creationist in question was a thoughtful honest individual your puzzle would be puzzling however if you question such people at length on a variety of other topics the cause of it becomes very clear. They are profoundly and willfully ignorant.

Starboy

[Mr.Vicchio]

Quote by: Starboy If the creationist in question was a thoughtful honest individual your puzzle would be puzzling however if you question such people at length on a variety of other topics the cause of it becomes very clear. They are profoundly and willfully ignorant. Starboy

Ahhh, more insults against people that have differing views then you eh?

Grow up.

[Savant]

Clearly there used to be meat flavored fruits in the garden of Eden. Duh! All we need to do is find the fossil of a meat fruit and Creationism will be validated! Glory to god! Seek the meat fruit!

(For any Christians that are interested, I am forming an expedition to seek the meat fruit, but we need funds! PM me for paypal info - give a Love gift that will help us bring scientific glory to God, Praise Him!)

[Starboy]

Quote by: Mr.Vicchio Ahhh, more insults against people that have differing views then you eh? Grow up.

My, my. Sounds like you identify with such creationists.

Starboy

[gallo]

Quote by: Mr.Vicchio Ahhh, more insults against people that have differing views then you eh? Grow up.

Perhaps you would like to tell us how to reconcile this finding with young earth creationism. The whole article is available at the link. Please offer some reasonable discussion. Show that ridicule is not justified.

[Mr.Vicchio]

I never have EVER claimed to be a "creationist"

I do however respect thier right to that view. I think it's wrong, but I am secure in my views enough to not resort ot insulting others to make myself feel better.

The Biblical account of Genisis IMHO was God's way of explaining life and reality to early man. Nothing more, nothing less. God created the Universe, set things in motion based on the laws of reality that we interact with on a daily basis and sat back and watched his creation unfold. I am a Spiritual Christian, therefore I can perfectly accept evolution as fact, and God's hand at work. It's really one in the same.

Why is that so hard to accept?

[Mr.Vicchio]

BTW one more point, were there any pur ecreationist on this board, they'd probably take one look at SB's post and decide it's not worth getting into a debate with someone whose main tactic is to insult them.

Why should they bother?


Grow Up.

[Starboy]

Mr. Vicchio, you seem to take offense about a comment you agree with. Perhaps you are just making a mindless knee jerk display.

Starboy

[Mr.Vicchio]

No, I am standing up to insulting behavior, I do not agree with the creationist that God made everything 6k years ago and that's that, nor do I accept that evolution is "bunk"

That being said, you are a IMHO a negative influence on any thread which deals with religion. In this case, you insulted fellow belivers and that, offended me. You sir, need to grow up.

[Starboy]

Mr. Vicchio, are you trying to tell me that there are not people who take the bible literally and maintain this state of knowlege by willfully ignoring and discounting scientific knowledge?

Starboy

[Matt W]

That's it. Back up, chill out, no more off-topic posts on here by ANYONE. Understood?

Do not respond to me within this post. PM myself or Sean if you have any questions.

[Mr.Vicchio]

Rgr that MattW.

Thanks for stepping in.

[gallo]

Quote by: Mr.Vicchio I never have EVER claimed to be a "creationist" I do however respect thier right to that view. I think it's wrong, but I am secure in my views enough to not resort ot insulting others to make myself feel better.

Sorry. I misunderstood you motives. I was looking for some rational discussion if possible. None seems to be forthcoming so far. I hope that you aren't right that it has been shut off by insult.

Quote by: Mr. Vicchio The Biblical account of Genisis IMHO was God's way of explaining life and reality to early man. Nothing more, nothing less.

On the other hand, god could be man's way of explaining natural phenenoma that he didn't understand. Gods threw the lightening bolts, gods caused the floods, gods inflicted mankind with plagues and disease as punishment for sins.

Quote by: Mr. Vicchio God created the Universe, set things in motion based on the laws of reality that we interact with on a daily basis and sat back and watched his creation unfold. I am a Spiritual Christian, therefore I can perfectly accept evolution as fact, and God's hand at work. It's really one in the same.

Well, that' one way of looking at it except that it is all so unnecessary. Why postulate supernatural beings where none are necessary.

Quote by: Mr. Vicchio Why is that so hard to accept?

Well, there just isn't any evidence for any of it.

So back to the cats.

[Mr.Vicchio]

I take all the evidence into account Gallo. The universe sprang form the "Big Bang" and randomly formed all that is on Earth... by chance?

I just cannot accept that rationally. There is too much order to the chaos, and for that there had to be a guiding hand, God's hand. That doesn't mean I expect to find his plainly written signiture, but if you look... it's there.

This is an example of that work in progress. We can merely observe the effects of the laws of the universe on the Macro, and micro scale.

Like you cats for example.

[Starboy]

Quote by: Mr.Vicchio I take all the evidence into account Gallo. The universe sprang form the "Big Bang" and randomly formed all that is on Earth... by chance?

The scientific explanation contains chance but is not entirely based on chance. It does presume that there were rules in place even at the earliest moment of the big bang.

I just cannot accept that rationally. There is too much order to the chaos, and for that there had to be a guiding hand, God's hand. That doesn't mean I expect to find his plainly written signiture, but if you look... it's there.

No one is asking you to. But if you claim you have a better exlanation that accounts for what has been discovered then bring it on. Go get your Nobel Prize.

This is an example of that work in progress. We can merely observe the effects of the laws of the universe on the Macro, and micro scale.

Agreed. And an honest person would not jump to conclusions and claim to have the answer when honestly no one knows.

Starboy

[gallo]

Quote by: Mr.Vicchio I take all the evidence into account Gallo. The universe sprang form the "Big Bang" and randomly formed all that is on Earth... by chance? I just cannot accept that rationally. There is too much order to the chaos, and for that there had to be a guiding hand, God's hand. That doesn't mean I expect to find his plainly written signiture, but if you look... it's there.

Ah. Then I was unaware that there was some sort of physical evidence for a god. Please start another thread and tell us about it. So far you have offered just what I said is the explanation for god. What you don't understand, you attribute to god.

Quote by: Mr.Vicchio This is an example of that work in progress. We can merely observe the effects of the laws of the universe on the Macro, and micro scale. Like you cats for example.

But you just avoid the opportunity to comment. I realize that you aren't a young earth creationist, but what impact does the research have on your view of this work in progress. What was god's purpose? If this is just an example of the laws of the universe in action, why isn't the big bang just another example?

I would also be interested in hearing from some young earth creationists with their opinion of how this came about.

[oranged]

Quote by: Starboy If the creationist in question was a thoughtful honest individual your puzzle would be puzzling however if you question such people at length on a variety of other topics the cause of it becomes very clear. They are profoundly and willfully ignorant. Starboy

As soon as I saw this thread I knew the only person who could turn kittycats not liking sugar into some kind of Insult was you Starboy.

[Starboy]

Quote by: oranged As soon as I saw this thread I knew the only person who could turn kittycats not liking sugar into some kind of Insult was you Starboy.

oranged, did you take the time to read the last paragraph of the opening post? It is funny as hell how people who complain about what I do to threads are the actual culprits. If you don't want to address the opening post then don't do it. But bitching about people that do is just stupid.

Starboy

[carriew]

Quote by: gallo . However, I fail to see how this finding could support the assertion by creationists that cats were once vegetarians that ate fruit.

my daughters cat loves cantelope and likes a few other melons like honeydew/watermelon.

can someone explain to me exactly what a creationist so I can know if I am one or not hehe...