In Focus
Researchers reveal process of making
ribs
" Like all vertebrates, snakes, mice and humans have in common a
skeleton made of segments, the vertebrae. But a snake has between
200-400 ribs extending from all vertebrae, from the neck to the
tail-end, whereas mice have only 13 pairs of ribs, and humans have 12
pairs, in both cases making up the ribcage.
In the latest issue of Developmental Cell, researchers from the
Instituto Gulbenkian de Cilancia, in Portugal, reveal that, contrary to
what was thought, making ribs is not the default state for vertebrates,
but is actually an active process of balancing the activities of a
remarkable class of genes -the Hox genes.
It was thought that the rib less region of the mouse embryo was the
result of a rib-inhibiting program, driven by Hox10 genes. Indeed,
previous studies, in which Hox10 genes were inactivated in the embryo,
generated mice with extra ribs. However, by forcing another class of Hox
genes (Hox6) to be activated in future rib-less regions of the mouse
embryo, Moises Mallo and his team bred mice that also have extra ribs,
both in the neck area, and from just after the rib cage, all the way
down to the tail, resembling a snake-like skeleton.
"It was an extraordinary, and clear-cut result," says Mallo,
"suggesting that these two groups of Hox genes balance each other out:
one actively promotes rib formation to produce the thoracic region,
while the other blocks this activity in the lumbar region. Our results
have unveiled this balance." The researchers went on to unpick the genes
involved in this process, and came up with yet another surprising
finding: that the whole process relies on first hitting so-called muscle
genes in the embryo, which then provide signals to switch on the 'rib'
genes to make both ribs and muscle, in a coordinated process.
According to Mallo, "Our findings reveal a more complicated process
than we would have imagined, but one that makes perfect sense, from a
functional and evolutionary point of view: it is no good to make ribs
without muscle, so, in the embryo, the production of both ribs and their
associated muscles is under the control of a single and coordinated
mechanism."
Courtesy: Science
Daily
Don't tolerate
abuse, call the hot line

Child abuse is taking place in many parts of the country today. Even
while you read this article a helpless child is being subjected to
abuse, somewhere in this land. Perhaps he or she is suffering silently,
unable to their cry out for help, out of fear.There are many such abused
children. You can be their voice.
No child should be robbed of his/her childhood or innocence because
of an immoral or cruel act of a heartless adult. If you are a victim of
abuse or know of any child who is being abused, pluck up courage and
reach out for that phone. A hotline has been set up by the National
Child Protection Authority (NCPA) especially for YOU.
However, don't be hasty to mix up discipline with child abuse. Some
children tend to believe that discipline is tantamount to child abuse.
First know the difference. No parent would discipline a child by causing
that child to undergo severe physical or mental trauma. Even if any form
of physical punishment is exercised, it would not be harmful. So, be
aware, be alert and be protected. Do not tolerate abuse any more. |