Single-Celled Species' Genome As Complex As Ours? 288
An anonymous reader writes: "A new paper reports on the sequencing and analysis of the genome of a single-celled species known as Tetrahymena thermophila. This ciliate (like the Paramecium people look at in school) has some 27,000 genes, or nearly as many as humans. And despite existing as a single cell, this spcies encodes fantastic complexity and unusual features. For example, it has a primitive immune system that prevents the invasion of foreign DNA. Also, it is able to cordon off its germ cell lineage much as humans do with sperm and eggs. But Tetrahymena does this by having two nuclei within each cell, with one of the nuclei being held in reserve for sex. Basically, this species uses its genome complexity to function like a single celled chameleon, changing its shape and its properties in response to the changing environment. For example, when a new nutrient shows up in its neighborhood this species can build a kit to suck the nutrient in, degrade it, and turn it into cellular biomass quickly. Thus whereas humans use their genomic complexity in part to create a stable environment for the body, this species simply uses a genomic swiss army kit to make do with whatever environment it encounters."
Interesting from a metabolic perspective (Score:4, Interesting)
I am actually pretty interested in this species from a metabolomic perspective. Organisms that can tune their physiology have a lot to teach us about the ability of metabolic networks to respond to environmental challenge or optimize their function in response to stress/disease.
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http://world4.monstersgame.co.uk/?ac=vid&vid=4701
Darwin All Over Again (Score:5, Insightful)
Then a few years later, people were amazed that a simple worm has 20,000 genes [genomebiology.com]. <sarcasm> How could it be that such a simple lowly creature has so many genes? Isn't more better? How could humans be beat? Blasphemy! </sarcasm>
And now it's 'news' that a single cell's genome has as many genes as a human's! When will we learn that the number of genes doesn't mean 'more advanced' or 'better off'? If this single celled organism's environment caused it to evolve more genes but physically change (seemingly) very little, why are we surprised?
Re:Darwin All Over Again (Score:5, Insightful)
Re:Darwin All Over Again (Score:5, Insightful)
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So we vertebrates are running Genome v. 3.5432, while bacteria are running Genome v. 453256.124
Re:Darwin All Over Again (Score:5, Insightful)
One of the standard tasks of teachers of biology courses is to disabuse the students of such notions. "Higher" and "lower" are value judgements that are biologically meaningless. Such terms might be appropriate in a religious context, but in a biological context they merely indicate cluelessness.
The "lowest" creatures on Earth have just as long an evolutionary history as ours, and are about as well-adapted to their niches as we are to ours. Single-celled organisms may be slightly better adapted, since they mostly have a shorter breeding cycle than we do. But given the universality of changing conditions, this generally doesn't mean a whole lot. The default assumption should be that most species are about equally well adapted to their niche. It takes evidence of special conditions to invalidate this.
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Re:Darwin All Over Again (Score:4, Interesting)
Oh, and if we survive after the sun envelopes the Earth, I think it's pretty likely that we'll take bacteria with us - and that we'll find bacteria already there when we get where we're going!
Re:Darwin All Over Again (Score:5, Interesting)
Don't bet on this.
Back in the 1960s and 70s, there were a number of papers written by astronomers about the Earth's "dust tail", equivalent to a comet's tail, and made of particles of the outer atmosphere blown off by the solar wind. This was of some significance for long exposures in the part of the sky behind the tail.
The studies showed that the Earth's dust tail is mostly gases, but also includes small dust particles, including particles the size of bacterial spores. Further study showed that the upper atmosphere does in fact have a small number of such particles, including bacterial spores. More studies showed that many bacterial spores can survive conditions in space for a rather long time.
So the Earth is spewing a tail of gases, dust and bacterial spores into interplanetary space. The solar wind blows this outward. A small amount hits the outer planets (and "dwarf planets"
This has probably been going on for 3 to 4 billion years. The Earth makes an orbit of the galaxy in about 220 million years. So we've made a dozen or more circuits of the galaxy, broadcasting bacterial spores the whole time. Calculations show that these spores by now have totally permeated the galaxy, and may have reached the Magellanic clouds, but probably not more distant galaxies.
There's a certain amount of conjecture here, of course. We don't actually know that bacterial spores are viable for the millions of years that it would take to reach other star systems. Few of them would ever encounter another planet where they could wake up and start living again. But over a few billion years, with a few billion spores per year (not much mass, really), small chances add up.
Some have suggested that this could be how life reached Earth. Google for the "panspermia" hypothesis for more information. There could well be other planets in the galaxy that are similarly broadcasting bacterial spores. Some of them could have been doing it for 12 billion years or so.
It's interesting to think about. Over billions of years, the Earth may not be as isolated as we might like to believe.
Re:Darwin All Over Again (Score:5, Insightful)
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Interesting critter.
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Re:Darwin All Over Again (Score:5, Funny)
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Of course, due to zoning laws, the mammalian committee ended up running a toxic waste pipe through a playground. Damn civil engineers...
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OR maybe we were not meant to have those abilities. I wouldn't trade my capacity for thought and imagination for awesome eyes... bigger penis maybe, but better eyes, come on...
Human eyes aren't optimized (Score:5, Interesting)
The human eye has a "design" error, in that the photosensitive layer is not in front, there are other cells above them. This means that the neurons that do the image processing functions in the retina must be transparent, and even so there is some absorption and scattering of light. Also, we have a blind spot in the retina where the optical nerve crosses the photosensitive layer.
In mollusks, OTOH, the outer layer of cells is the photosensitive one. The eye is more sensitive to light, has no blind spot, and allows for more data processing in the retina itself. That may be one of the reasons why octopuses are so good at camouflage, their eyes are very sensitive.
All this is one more argument for evolution and against the "intelligent design" theory.
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So if you were the lead designer of an MMORPG, would you create a class that's the best at everything? The Architect obviously didn't want us to be too munchkinish.
Now if you'll excuse me, I'll keep on trying SQL Injection attacks on this Universe app.
Re:Human eyes aren't optimized (Score:5, Informative)
Actually, the mammalian (human) eye is optimized for the metabolic loads it requires. It turns out that there is no higher area of metabolism in your body than there is at the photoreceptor/retinal pigment epithelium interface. It is a highly oxidative environment and evolutionarily, you need the apposition of the photoreceptors up against a layer of cells that can deal with the shed outer segments and the metabolic loads induced by rod photoreceptors. The other advantage is that you can snuggle the photoreceptors up to these cells that have a direct connection (diffusion) to a vascular layer. If it were backwards, the blood vessels would get in the way of the image formation and cast shadows.
In mollusks, OTOH, the outer layer of cells is the photosensitive one. The eye is more sensitive to light, has no blind spot, and allows for more data processing in the retina itself. That may be one of the reasons why octopuses are so good at camouflage, their eyes are very sensitive.
Octopuses, squid, and cuttlefish have fairly sophisticated retinas that is true and you are correct about their anatomy. However, they do not process the same metabolic loads that the mammalian retina does and thus do not require the same degree of buffering, care and feeding that mammalian photoreceptors do. You have to be careful about using "sensitive" to describe eyes as that descriptive is dependent upon lots of things. Typically in most retinas it has to do with the ability of the opsin to capture a photon and the cell the opsin is in to transduce that signal.
All this is one more argument for evolution and against the "intelligent design" theory.
Intelligent design (ID) really does not even factor into either argument. ID is a religiously/politically motivated belief, not a theory that can be tested.
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The human eye works well enough for humans. We don't need that extra visual data. Dogs have much better olfactory and audio sensing than humans. The great apes are much stronger. It can be argued that the human eye is optimized for the human life style.
Not really a good argument against intelligent design since there is a counter argument that if that design for an eye was so much better than what humans have why didn't humans get this better eye?
There are a great many argume
Re:Human eyes aren't optimized (Score:5, Insightful)
- The majority of the sensors on it are completely overwhelmed in moderate light conditions, and are only useful at dusk.
- The resolution is very poor in the receptors that work in colour, and the high-resolution ones don't work at high light levels.
- The connection to the is seriously underspec'd (by a couple of orders of magnitude. Someone put a decimal point in the wrong place on the Intelligent Designs, perhaps?).
- The compression used to make up for the previous deficiency has serious bugs. These include the inability to properly transmit certain shapes, and the lack of absolute colour information. I wonder if our Intelligent Designer also worked on NTSC...
- As a previous poster mentioned, the connector for the uplink is badly wired and obscures the sensor.
- Very poor design tolerances. Only about 20% seem to be manufactured without any kind of defect.
If you've looked at the human brain recently, you will note that a volume similar to that of the eyes is dedicated to bug-fixes and work-arounds for poor design of the eyes themselves.If the human eye is the best our Intelligent Designer can come up with, perhaps someone could point me in the direction of his Intelligent Bug-Tracking System.
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- Why are our (male's) balls so badly protected? Why aren't they inside our body?
- Why are our brains so prone to chemical imbalances causing depressions and such?
- Why are girls able to get pregnant before their body can succesfully go through pregnancy and have an healthy child?
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-Why do the air and food passages cross in our throat? Making them totally separate from each other would prevent us from choking.
-Why is the biggest and most important nerve in the body intertwined with the bones in the spine? It should follow a separate and more protected path inside the body.
-Why do we have a single bone, the femur, in the thigh, but two separate bones in the ankle? These bones ar
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Because God foresaw "Funniest Home Videos" & "YouTube". C'mon, guys, that's what "omniscent" means !
Because God likes to laugh at crazies just as much as you do. He created you in His own image, remember?
For the same reasons w
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2. How do you think anti-depressants work? Magic?
3. There are also many cases of the opposite. Which doesn't say much about the "intelligent design" process.
Anyway, this arguments are silly. The bottom line is - anyone will have a hard time proving (or even defending) that we were intelligently designed. At least, if you're trying to prove it to someone who is him/herself intelligent enough to think about what's being said.
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Re:Darwin All Over Again (Score:5, Insightful)
In actuallity, survival of the fittest implies fittness for a certain environment only. To borrow someone else's analogy, you can have the best gills in the pond and you'll still die off with the rest if the pond dries up.
The problem is really the human ego; we have an enourmously hard time accepting the idea that humans aren't innately special. We're intelligent, certainly, and we're unique, but then again every species that has a highly specialized survival strategy is unique.
Re:Darwin All Over Again (Score:4, Insightful)
The problem is really the human ego; we have an enourmously hard time accepting the idea that humans aren't innately special.
I tend to think that our survival strategy is highly generalized and superior to all other survival strategies.
We can survive in outer space, on the moon, in heat so hot that it would kill any other lifeform, and in pressures so intense that nothing else can live in them because of our survival strategy (use intelligence to survive harsh conditions).
No other species on Earth has this degree of adaptability to different environments. I believe that it is specifically this adaptability beyond that of anything else that gives man his feeling of superiority - of being a "higher life form". Is that enough to justify such a stance?
I don't know. Even if it isn't, not being superior is no reason to doubt the obvious: we are the most adaptable species on the planet to different environments.
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Re:Darwin All Over Again (Score:5, Insightful)
Our survival is essentially rooted in toolmaking and inventiveness. There are other examples of species that employ tools, but none to the same degree that we do. Virtually everything that we need to survive, and everything that sets us apart, is rooted in this adaptation.
This is not the survival strategy of a generalist, it's the way of a specialist. We've got all our eggs in one basket. That basket has paid off in many unique and useful ways, which allow us to do things like survive in environments that are radically different from the ones we initially evolved in, but fundamentally we're still specialized.
The environment we're fit for is a technological one, rather than a geographic one.
Does this make us unique? Yep, but that's hardly an unusual affair for specialized animals. Does that make us intelligent? Hell yeah, but then we only consider intelligence/sapience so important because it's the only shtick we've got. There's a quote that goes something like "I used to think the mind was the most interesting part of a person - then I thought 'hey, wait, look who's telling me that'", which sums up our emphasis on brains quite nicely.
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One of the unique aspects of humanity makes it really hard to make that statement.
Instead of considering a single human, consider "the human gene pool", in the "selfish
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Were things to get really bad, (Eg: A bigass comet smashing into the earth), there are plenty of "lesser" species whos chanc
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http://www.wired.com/wired/archive/12.12/dive.htm
And they saw a fish.
The deepest recorded ocean depth is 36,201 feet.
You telling me that there is no life in that last 400 feet and beyond ?
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blame the Bible (Score:2, Insightful)
Thanks to that phrase, people think humans are superior to all other forms of life. Everything else was put there for us to exploit. We don't have to live in any sort of harmony, it's all just for the consumption of us superior beings.
Don't get me wrong, I eat cows, pigs, and all that with the best of them. But I do that because I'm an omnivore, not because I'm superior to a fish.
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Maybe you'd be better off without the beer goggles.
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Adaptability - an objective measure of superiority (Score:5, Insightful)
It's always seemed to me that there *is* an objective criterion for superiority in a species. Since we're judging superiority as fitness or the ability for a certain pattern (the genome) to continue propagating, then the superior species would be that one most able to overcome a greater variety of possible roadblocks to it's survival. To use your analogy, an amphibious fish, with watertight skin that can also breath air, would be objectively better by these criteria because it doesn't need the pond. It can live on land if need be.
In short, adaptability is what makes a species "superior". This is what has made homo sapiens the dominant large animal species on the planet - our intelligence has allowed us to adapt to damn near every (land) niche on the planet. Rats are a highly fit species for this same reason, as are cockroaches, and many fungi and microorganisms. All of these species are well-rounded and adaptable. (And by this criteria, this new species featured in TFA is likewise highly advanced). The one thing that I can see possibly giving mankind an edge up out of that group is our ability to radically change and even create environments around us, most notably including the ability to leave this planet of our own volition. (While some spores can survive in space, they couldn't just pack up and leave when the sun goes Red Giant on us all. We might be able to).
And since highly adaptable species are more fit to survive over longer periods of time, then evolutionary pressure *will* tend to select for them. And in that sense there is a sort of teleology to evolution: over time, as environments change back and forth and around to a variety of different extremes, the most flexible, adaptable, and generally well-rounded species will tend to outlive the rest. To survive in particular niches against competition from species specialized to those niches, they will have to become more capable in many areas as well; not simply jacks of all trades, but also aces of many.
You're certainly right that the old concepts of some sort of linear progression culminating in mankind are inaccurate. But that doesn't mean you have to deny any sort of progression, or any sort of objective criteria for discerning superiority or fitness between species.
Re:Adaptability - an objective measure of superior (Score:4, Insightful)
The objective criteria you mention must take the organism's habitat into account. You know this, I know this, but the problem is that many other people don't know this. The phrase "survival of the fittest" without the qualifier is what most people understand evolution to be, as if there were some measure of fittness that wasn't relative and subjective. This in turn leads to all sorts of misunderstandings about how evolution works, the most disturbing of which can be seen in 19th century social darwinism.
Plus, it's worth noting that not all evolutionary progress pays off. To get back to your own counterpoint about amphibious fish surviving when the pond dries up, those same fish would be a less successful species right up until the point where the water based life dies. They'd probably be a marginal species that outlives the specialists by a stroke of luck.
This is where genetic diversity matters - you never know what sort of arraingment is going to work best in the future. Often the generalists outlive the specialists, and humans are definately in the specialist category (we're completely dependant on man-made tools to survive).
As for us humans, I would argue that our environment is a technological one, and that we only consider ourselves highly evolved because we're basing our criteria on ourselves. In other words, our survival strategy is toolmaking, so we're biased in favour of that strategy over any other. I don't think it's possible to look at what we've evolved for objectively, anymore than an individual can judge themselves impartially. And it's way to easy to get into circular reasoning.
Re:Adaptability - an objective measure of superior (Score:2)
As far as 'fitness' or 'superiorty', you're delving into teleology there. I'm very keen on hearing your argument as to why reproducing is 'better', in any objective, scientific sense, than going extinct. My f
Re:Adaptability - an objective measure of superior (Score:2)
Re:Adaptability - an objective measure of superior (Score:3, Insightful)
To talk a bit more about humanity's being special, its in large part in the brain. I would wager that almost every other bioli
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Umm....doesn't it? That seems to be the reason why it's got so many genes.
It uses them to be able to adapt to it's environment. Which makes it more advanced, and better off than other single-celled organisms with fewer genes.
More genes=more genetic information to draw from=probably better off.
The only reason it wouldn't be true is if the i
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Here's an analogy:
It's similar to saying that sophistication of manipulation is a function of how many fingers one has. That's not correct - you need specific muscle placement, fine motor and sensory func
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It uses them to be able to adapt to it's environment. Which makes it more advanced, and better off than other single-celled organisms with fewer genes.
That's about like arguing that a larger program is better than a smaller one. The truth is that sometimes bigger is better, sometimes smaller is better; It all depends on the content of the code (computer or genetic). If the larger program does more and does it better, it may w
Darwin never said that (Score:5, Informative)
I feel it's worth pointing out that no where in the Origin of Species does Darwin discuss human/great ape/primate evolution. I'm not even certain he used the word "evolution", but don't quote me on that. Also, no true evolutionary biologist has ever said that humans descended from monkeys. It's that whole common ancestor thing. Lot's of branches, not straight line.
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Insects and bacteria are probably "better off" than humans, if you go by number of individuals or total biomass. There are probably more mosquitos in Panama than people on Earth. (just a guess) very successful species.
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I guess the development of higher brain function is a sort of "universal adaptor" for enviromental stresse
Re:Libs & Conservatives agree (Score:2)
Yep. Now we have to agree on what "science" IS...
Try to Agree, not disagree (Score:2)
You make a good point, but like I said, you don't want to try to split us apart into 2 parties right away again. So, we need to look for the next logical step, go down as far as we can with the parts we agree upon instead of immediately pointing out the parts we disagree on.
Rough Example:
Re:Try to Agree, not disagree (Score:5, Insightful)
1) Start with an explanation of what science is. At its core, science is the ongoing effort to understand our world and the universe around it, how it works, and how it came to be. Specifically, science is intended to look at the world impartially and judge it only on proveable, repeatable observations. Science is the practice of observing facts and forming opinions based solely on those facts.
2) Define a scientific theory. It's not "just a guess". A true theory is supported by all the available facts, and can be used to predict further observations. When a theory is proven wrong, it is either modified (as evolution has been many times) or thrown out entirely.
3) Explain the basics of evolution. Point out that it describes a system of nature, and not just an order of progression. The theory of evolution is not the idea that man evolved from monkeys. The idea comes from the theory, but is not an integral part of it. Evolution at its most basic level is simply stated as "life changes".
I've put it this way before: Would you agree that every generation of humanity is somehow different than the last? That with each generation, some individuals never reproduce and some are far more successful (have more kids) than others? Does that not change the gene pool for the entire species? Every generation, the gene pool changes a little bit. When those changes are cumulative, that's evolution.
4) If the subject comes up, address the fact that evolution has never been meant as a direct challenge to any faith or belief. It is simply the best model for explaining the scientific observations available. It can be contradicted tomorrow, should sufficient observations be made.
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Surely it would take at least six days of hard work to compile enough observations to contradict evolution. One the seventh day you could rest though.
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There is nothing in your post that a Creationist would disagree with. Define evolution as a "change in allele frequencies in a population over time" and you will find Creationists nod
To the mod who modded parent "flamebait": (Score:2)
NOT posting A.C. to illustrate that the identities of the moderators of a post should be visible as well (which should explain why I've used a grand total of ONE moderator point. Ever.)
Re:Libs & Conservatives agree (Score:2)
Because they pay most of the taxes, and so when taxes are cut they're the one who see most of the cuts. I'm far from wealthy, but benefited from Bush's tax cuts.
and raised spending, sending the deficit higher than it's ever been before?
Because Bush's dad never taught him to balance a check book?
Under Clinton we were paying it off.
Under Clinton we had a propped-up economy full of ongoing accounting scandals like Enron. I'm not saying tha
Re:Libs & Conservatives agree (Score:2)
It's true that the vast majority of people in America have the same goals: Be safe, protect our rights, educate our children, and ensure they have the same or better opportunities than we do. What you don't seem to get is that we all have different ideas on how to go about doing that.
Just look at education: A lot of people are just fine with the status quo. Plenty more would rather see our public school system converted into religious schools. I've also seen movements to
Evolutionary quagmire (Score:5, Funny)
Hot.
> when a new nutrient shows up in its neighborhood this species can build a kit to suck the nutrient in, degrade it,
I like where this is goin'.
> and turn it into cellular biomass quickly.
Giggity giggity goo!
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And she said size mattered. Ha! I was just holding back the rest of it in reserve...
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I'll take one for the team here. (Score:2, Funny)
Tetrahymena (Score:5, Informative)
http://en.wikipedia.org/wiki/Tetrahymena [wikipedia.org]
Darwin himself said it best (Score:2, Interesting)
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Re:Darwin himself said it best (Score:5, Insightful)
What Darwin was saying was essentially that if an organ were encountered that could not have developed incrementally, then that would disprove his theory. People have tried to show that the eye meets this criteria, but we now know that light sensing organs can develop incrementally. Wings have also been brought up as a potential arguement, but are counteracted by examples of wing-like structures that serve some intermediate purpose other than flight.
Plus, gene count does increase incrementally, so even if Darwin had used the word organism, your answer would still be "no". Gene count is really pretty irrelevant as a measure of complexity, and in any case is easy to increase slowly over time with mutation.
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>but we now know that light sensing organs can develop
>incrementally.
Out of curiousity, we know this how?
Re:Darwin himself said it best (Score:4, Informative)
http://en.wikipedia.org/wiki/Evolution_of_the_eye [wikipedia.org]
Short version: We now know that patches of photoreceptive cells can develop without the surrounding structure of the eye. Furthermore, having minimal sight is substantially better than no sight whatsoever, so even "half an eye" is workable from an evolutionary perspective.
So incremental development is possible, beginning with a retinal precursor, and slowly developing layers of complexity that give rise to the various types of eye (for example, human eyes and compound eyes, which are dissimilar in configuration, but serve the same function).
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Re:Darwin himself said it best (Score:4, Funny)
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Even "incrementally" is a bit of a challenge to define here. It sounds like this organism may have started as two separate ones that developed a symbiosis, then merged completely. That would appear as a rather sudden change in the genome, adding thousands of genes at once rather than reinforcing one new mutated allele.
It's rare, but it does happen. You yourself have a sp
# of genes != complexity (Score:5, Insightful)
Evolution doesn't stop (Score:3, Interesting)
Yet again I'm reminded that evolution doesn't stop and that these "simple" organisms have had just as much selection applied to their genome as the more "complex" organisms. People think of evolution as simple bacteria turning into more complicated multicellular organisms, which then turned into more complex animals and eventually the pinnacle of evolution, people.
The reality is that evolution doesn't have a goal and that single celled life is just as rich and complex as any of the more sup
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Nature tends toward efficiency. Just because we don't currently know what something is for is no reason to suspect it has no function, and until you know every asp
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That figures... (Score:3, Funny)
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Well, there's that.
Plus the fact that Garden Gnomes aren't alive. Oh, and next time you decide to get drunk, and scream about killing our Garden Gnomes whilst pummeling them with a wiffle bat, please stay out of the rosebushes, and don't pee on the lawn.
Thank you.
Sincerely,
The Neighbours
Interesting (Score:5, Interesting)
Superficially (Score:2)
And for most of them it's true. Others appear to have a ton of junk in their DNA that doesn't code for anything. Heck, that's the most interesting part of this - the really interesting question is "do they activate reserve DNA in a directed fashion" - i.e., are the heat-tolerant genes activated by heat, the drought-tolerant genes activated by drought or are they activated by the normal process of random variation of individuals?
Darwin didn't know Genetics (Score:2, Informative)
Pete is looking for a replacement (Score:2, Funny)
"this species simply uses a genomic swiss army kit to make do with whatever environment it encounters."
Give it a couple million years of natural selection and you'll get a Phoenix Foundation employee of the month.IT section!? (Score:3, Informative)
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They've been around a long time! (Score:4, Insightful)
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How many active genes? (Score:2)
I mean, that's what matters, isn't it?
Although I guess it can be interesting as a curiosity if it has many inactive genes...
buzz buzz buzz (Score:2)
That is so vastly over-simplified, over-analogized, and over-metaphorized as to be practically devoid of meaning.
Gene number... (Score:4, Interesting)
Beadle and Tatum's original hypothesis that "One gene encodes one enzyme" no longer holds true. Mechanisms such as alternative splicing and epigenomic effects (gene activation and silencing) can cause one gene to produce many isoforms, each which may be active differently between tissue types, and each which may have entirely different functions. Our 27,000 genes are quite possibly far more complex than another species 27,000.
Awwww (Score:5, Funny)
Single Cell Swiss Army Knife... (Score:2, Interesting)
Is this supposed to be a shocker? (Score:2)
I think evolution is fundamentally misunderstood by people. If you think about it a modern disease, ape, plant, bird, etc. isn't any less advanced than a modern human. Everything adapts to its environment, so we all gain complexity as we move toward survival and reproduction. It's a tree structure, not a simple line, w
all mammals similar (Score:3, Informative)
The human genome betting pool paid off at 23,299 genes in 2004, though some people suspect a few more. Most sequenced mammals appear to have about 3 billion base pairs and 25K genes. The highest animal number I heard was the puffer fish at 39K genes. The record appears the amoeba dubia at 670 billion base pairs.
Mammalian gene storage and expression is more complicated than bacteria. Dr. Watson said the typical gene is divided into eight segments (exons) with some approaching 30. Plus these may code for multiple proteins. Some biochemical stores sell DNA genes with the introns removed (cDNA). These are made from RNA templates found cells and turned back into continginuous DNA. There are about twice as many cDNAs for a mouse than there are genomes.
What's simple about it? (Score:2)
Why did you put the word "simply" in there, when it makes no sense in that context? Feeling extra verbose today?
Genome size does not equal complexity (Score:3, Informative)
Cost/benefit a factor (Score:3, Informative)
If our ancestors did not have to run from or hunt fast mean animals, then perhaps our genome would pile up with "in-case" genes also. Appearently this organism uses flexibility instead of being the leanest to survive. Humans more or less also use this strategy, but by learning with brains, not via DNA. DNA is essentially a kind of long-term brain.
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EPIC! MAN! EPIC!
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Re:Alternative to Passive Natural Selection? (Score:4, Informative)
Don't give up the day job.