* Astronomy

A team of neuroscientists and zoologists of the University of Florida has concluded through genetic analysis that a prehistoric marine worm may be the ancestor of humans.
The half-inch-long creature known by its scientific name of Xenoturbella and first retrieved from the Baltic Sea more than 50 years ago has long puzzled scientists.
Now, Leonid Moroz, a professor of neuroscience and zoology at the University of Florida's Whitney Laboratory for Marine Bioscience, and 13 other scientists have reportedly discovered an organism that could establish a link between modern-day humans and the ancient chordates, the backboned animals that included humans.
Initially, these scientists say they discovered a mollusk-like DNA that resulted not from the creature itself, but from its close association to clams and their likely habit of eating mollusk eggs. They said the Xenoturbella did not seem to have a brain, a gut or gonads, making it unique among living animals.
According to their study, which appears in the journal- Nature -- more precise genomic sequencing resulted in the identification of about 1,300 genes, including mitochondrial genes. It was then found that the Xenoturbella belongs to its own phylum, a broad class of organisms lying just below kingdom in taxonomic classification. The scientists claim that it is one of only about 32 such phyla in the animal kingdom.
More significant was the confirmation that that human beings and other chordates share a common ancestor, a first in science.

"It is a basal organism, which by chance preserved the basal characteristics present in our common ancestor. This shows that our common ancestor doesn't have a brain but rather a diffuse neural system in the animal's surface" - Leonid Moroz.

A reconstructed genetic record implies that the brain might have been independently evolved more than twice in different animal lineages.

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A team of scientists has reconstructed the DNA sequence of a 5-million-year-old retrovirus and shown that it is able to produce infectious particles. The retrovirus--named Phoenix--is the ancestor of a large family of mobile DNA elements, some of which may play a role in cancer. The study, which is the first to generate an infectious retrovirus from a mobile element in the human genome, is considered a breakthrough for the field of retrovirus research. The findings are reported in Genome Research.

"Phoenix became frozen in time after it integrated into the human genome about 5 million years ago. In our study, we've recovered this ancestral state and shown that it has the potential for infectivity" - Dr. Thierry Heidmann, lead investigator on the project

Vertebrate creatures first began moving from the world's oceans to land about 415 million years ago, then all but disappeared by 360 million years ago. The fossil record contains few examples of animals with backbones for the next 15 million years, and then suddenly vertebrates show up again, this time for good.
The mysterious lull in vertebrate colonisation of land is known as Romer's Gap, named for the Yale University palaeontologist, Alfred Romer, who first recognised it. But the term has typically been applied only to pre-dinosaur amphibians, and there has been little understanding of why the gap occurred.
Now a team of scientists led by University of Washington palaeontologist Peter Ward has found a similar gap during the same period among non-marine arthropods, largely insects and spiders, and they believe a precipitous drop in the oxygen content of Earth's atmosphere is responsible.

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Fish developed features characteristic of land animals much earlier than once thought, say researchers.
Dr John Long of Museum Victoria and colleagues base their conclusions on an uncrushed 380 million-year-old fish fossil found in Western Australia.

"The specimen is the most perfect complete three-dimensional fish of its kind ever discovered in the whole world" - Dr John Long , who reports the team's findings online today in the journal Nature.

"It looks like it died yesterday. You can still open and close the mouth."

Long says the preserved remains of a Gogonasus fish from the Devonian period were found last year in the remote Kimberley area at the Gogo fossil site, once an 'ancient barrier reef' teeming with fish.

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