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SCIENCE UPDATE
Rare disease genes found
Another human chromosome has been mapped by an international team of scientists.
The complete genetic instructions held in chromosome 14 have been published online. It is the fourth chromosome to be decoded and contains more than 60 disease causing genes, as well as two crucial immune system codes.
The research could help scientists understand why some people are more likely to develop certain rare conditions including early onset Alzheimer’s.
The human genetic code, or genome, consists of three billion pairs of chemicals known as bases. These are arranged in 24 distinct bundles called chromosomes and are found in the nucleus of every cell in our bodies.
Scientists already have a rough draft of the entire human genome.
They are now trying to fill in some of the gaps in the data to come up with a “gold standard”.
In the last three years chromosomes 22, 21 and 20 have been decoded to this level.
In order to sequence chromosome 14 researchers looked at data from the human genome project.
But to help them locate some of the genes, the scientists compared fragments of chromosome 14 with the mouse and exofish genome.
The scientists found 1050 genes on the chromosome. The chromosome itself contains 87.4 million base pairs or building blocks of DNA.
But this is the first time that scientists believe they have left no gaps in the genetic sequence.
They have managed to find the location of not only specific genes that code for proteins, but also their start and stop signals for these genes.
Roland Heilig from the Genoscope-Centre National de Sequencage in France led one of the teams behind the work. He said that chromosome 14 has been mapped to the ‘gold standard’.
He said: “The identification of disease genes will help us find out how diseases develop at a molecular level.”
Chromosome 14 contains two genes which are crucial in making our immune system work properly. Another 60 genes have been found which can cause disease. They include genes involved in early onset Alzheimer’s and an extremely severe form of Usher syndrome, which affects hearing and vision.
Chromosome 14 also contains genes for Niemann-Pick disease, a very rare but deadly condition.
Developing treatments, like chromosome-specific drugs which could repair the damage in the genetic code, are a long way off but this work could help doctors screen for these genetic conditions.
The research is published online on the Nature website.
Ape ‘learns to talk’
A chimp who has grown up among humans may have developed the ability to talk, claims a research team from the US.
The findings, published in New Scientist magazine, may come under fire from other scientists.
But they may further challenge the long-held belief that apes have no language ability.
Kanzi, an adult pygmy chimp, is kept at Georgia State University in Atlanta, and, like many other primates, can communicate by pointing at symbols.
However, researchers recently noticed that he was also making gentle noises while he interacted with humans.
By studying many hours of videotape, Dr Jared Taglialatela and Dr Sue Savage-Rumbaugh spotted four distinct sounds that accompanied particular actions, corresponding to “banana”, “grapes”, “juice” and “yes”.
Even in different contexts, the chimp made the same sound.
Although the researchers conceded that the emotional state of the chimp might be to blame, the sound for “yes” stayed the same, even when Kanzi was in different emotional states.
Dr Taglialatela said: “We haven’t taught him this - he’s doing it on his own.
“That emotion is involved doesn’t rule out that he’s following rules that have some sort of cognitive component.”
The definition of what actually constitutes “language” is controversial.
Some linguists believe that even symbolic communication - which many chimps achieve - qualifies as language, but many now say that some mastery of syntax is also required.
Primatologist John Mitani of the University of Michigan in Ann Arbor said: “Despite the fact that we have had glimmerings of this in the monkey world, few instances of anything like this have been documented among our closest living relatives, chimps and bonobos.
“There have to be evolutionary precursors to what we do. We are beginning to find them in the primate world.” — Dawn ScienceDotcom Report
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