Fossil Find Is World's Oldest Insect

Scientists have identified the oldest known insect from its fossilized jaw
remains. A report published today in the journal Nature describes the
creature, which lived between 408 and 438 million years ago. The results
push back the earliest appearance of winged insects by nearly 80 million
years and suggest that the creatures were among the first animals to arrive
on land.

David A. Grimaldi of the American Museum of Natural History, who wrote the
paper with Michael S. Engel of the University of Kansas, describes the find
as "completely serendipitous." During the course of researching a book on
insect evolution, he explains, they were initially focused on another sample
stored in the vault of London's Natural History Museum. But the slide stored
next to it-a sample of chert (see top image) from Rhynie, Scotland,
initially studied in 1928-caught their interest, and they brought it back to
the U.S. for further study. "I remember sticking it under my microscope,"
Grimaldi says, "and Michael and I kind of looked at each other and said,
'Holy moly, do you see what I see? These are actual true insect mandibles
[jaw parts].'" Specifically, diagnostic features of the jaw's joint anatomy
(see bottom image) indicate that the remains belonged to a winged insect,
Rhyniognatha hirsti

The oldest known evidence of winged insects-that is, complete fossilized
bodies with fully formed wings attached--dates to around 330 million years
ago. But because there is a diversity of species capable of powered flight
from this time period, insects clearly evolved wings well before that time.
"This chert provides a tantalizing scrap of evidence to suggest that we're
missing a huge amount," Grimaldi remarks, "and there's probably this
wonderful progression of insects with protowings yet to be
discovered." --Sarah Graham

>From Scientific American
http://click.exacttarget.com/?fe8f1173736d017975-fe3016707360067c711779

Cloned Human Embryos Yield Stem Cells

Scientists in South Korea have succeeded in obtaining stem cells from cloned
human embryos. A report published online today by the journal Science
describes the work, in which 30 embryos of about 100 cells were created and
used to harvest stem cells that later differentiated into a variety of
tissue types. The findings offer hope for treating disease through so-called
therapeutic cloning but are sure to revive ethical debates.

The list of successfully cloned animals includes sheep, mice, horses and
cats, among others, but primates have proved difficult. In the new work, a
team of researchers led by Woo Suk Hwang of Seoul National University
collected 242 eggs from 16 unpaid volunteers who knew their eggs would be
used for scientific experiments. The scientists transferred the nucleus of a
somatic, or nonreproductive, cell into an egg from the same donor that had
had its nucleus removed. The researchers used a slightly different technique
to extract the contents of the egg-employing gentle extrusion instead of the
more commonly used suction method-which, together with careful timing and
the freshness of the donated eggs, may have aided their success.

http://click.exacttarget.com/?fe881173736d017e7d-fe3016707360067c711779

Posted by
Robert Karl Stonjek.
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