Posted on 12/17/2002 3:45:31 AM PST by Junior
WASHINGTON - Researchers have sequenced the gene structure of the sea squirt, a homely creature of the ocean bottom that has intrigued scientists since the days of ancient Greece.
In a report appearing Friday in the journal Science, 87 scientists from five countries announced they have correctly assembled the 150 million DNA base pairs of the sea squirt genome. The humble creature is the seventh animal to be genetically sequenced.
Mike Levine, a researcher at the University of California, Berkeley, and a co-author of the study, said studying the genetics of the sea squirt gives a glimpse at the very early history of evolution, a time more than 550 million years ago when animals with backbones were just beginning the shift toward a new age of complexity.
"The sea squirt enjoys a special place in the hearts of biologists because it provides the first evolutionary connection between invertebrates and vertebrates," Levine said. "You look at the adult and you think it is one simple creature, but if you look at the embryo, you see a clear connection to higher animals. This is our ancient, ancient cousin."
Adult sea squirts live fixed on the bottom in shallow ocean waters. The sea squirt has a rubbery, hollow body. Vents suck in seawater and shoot it out after filtering nutrients. It is this squirt of water that gives the animal its name.
Aristotle, the ancient Greek philosopher, studied the sea squirt and classified it as a mollusk. That stuck until the 1870s, when a Russian biologist recognized that the embryo of the sea squirt closely resembled a tadpole, with a head, tail and central nerve bundle called a notochord. It was this discovery that led scientists to understand that the sea squirt was actually a chordate, a member of the same animal phylum as humans.
"They're related to us," Levine said. "Charles Darwin called them our ancient relatives because they had a common ancestor with humans."
Studies showed that embryonic humans shared the same notochord structure as the embryo of the sea squirt. In humans, the structure goes on to become the central nervous system. In the sea squirt, the tadpole-like creature finds a place to grasp on the ocean floor and transforms into the tube-like adult.
The other animals to be genetically sequenced are human, mosquito, mouse, nematode, fruit fly and puffer fish. All but the human and mosquito are important laboratory research animals.
Levine said the sea squirt has 15,000 to 16,000 genes, about half of the number estimated for the human. The animals has about 150 million DNA base pairs, a fraction of the 3 billion found in humans.
The sea squirt is simple to manipulate and study in the lab. Levine said that the animals shares many of the same genes as humans and that studying the sea squirt researchers should be able to gain new understanding about how genes interact and regulated.
LBB's gonna be pissed. His contention that all genetics disproves evolution has hit another stumbling block.
Red meat, guys!
Just thought you'd enjoy this quote, Mr. "All Biology Disproves Evolution."
Instead of which it attaches itself head-down to the sea floor and spends the rest of its life acting more like a sponge.
In the end, it ain't really up to you, is it? I've got a brother I'd like to disown, but unfortunately I have no control over that situation.
Presumably it is aiming for the post of Republican Senate leader...
(Back from vacation with some of my more immediate relatives)
As they ignore everything which discomforts them. And when they can't ignore some things, they nevertheless refuse to connect the dots. So let the thread die. It doesn't make any difference. Evolution is so well-established that it doesn't matter what they think. Or say. Or do.
What claims? The only relevant claim being made is that the hollow tube has been sequenced. No other claim about that information has been made. The statement about the sea squirt's emulation of Christopher Reeve is a previously held opinion.
On the other hand, how do you fit this into the vertebrate/invertebrate split?
The squirt can also do things that we can't. It stiffens its adult body with cellulose, for example. Plants and bacteria use this tough molecule in their cell walls, and possess similar genes for making and breaking it.
Where are the lilies with the nerve cells?
A few other questions could be asked such as were are the descendants that turn from tadpoles to plant like creatures. How are they 'born twice'? Where are the ancestors and descendants of this creature if it is so unique? Also, why would such a whacked out creature survive some 500 million years with 'all this evolving going on'? NOt only survive - but have not changed in 500 million years! I thought species evolved all the time. Is that not what evolution is all about?
Problem with evolutionists, (and evolutionist reporters) is that they are so ignorant and lacking in common sense that they do not see that this organism strongly disproves evolution.
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