Technology has now been devised to reconstruct the genomes of animals who lived millions of years ago.Scientists cannot reliably recover DNA that is
more than 50,000 years old. To investigate older sequences, researchers have to rely on computer programs that infer backwards from present-day
animals. But this approach has been limited in the past because there was not enough information available about modern genomes. And the algorithms
used by such programs also had limitations: for example, they considered only one type of genetic mutation, known as substitution.
David Haussler of the University of California, Santa Cruz, and his colleagues decided it was time to put 'computational
genomics' to the test. To assess their method, they created a hypothetical portion of ancestral mammalian DNA and let a computer model simulate the
process of evolution, to generate sequences for its descendants.
Then they made their algorithm work backward from these descendants, to see if it could recreate the original ancestor. The ancestor the algorithm
came up with had a sequence that was 98% accurate, they report this week in Genome Research
Back to the future
The team took 19 modern mammals, including the pig, human and rat, and used the algorithm to work out the genome of their
common ancestor, thought to be a shrew-like animal that lived more than 70 million years ago. They focused on a small region of the genome that codes
for ten genes.
One surprising result was that, compared with the ancestral sequence, the human sequence has lost only 11% of the genetic units called bases, whereas
in rodents around 39% have been deleted. The researchers think this is probably because rats and similar animals go through generations more quickly,
so they accumulate mutations faster.
The comparison with the recreated ancestral DNA should give other researchers clues about how and when the various descendants branched off. "You
can see what special twists made each species different," says Haussler.
Some great Links with countless video rapresentaions,....enjoy
Citation has been Awarded to Pro.D.Haussler last year:
“For contributions bridging computer science and biology through research in computational learning theory, computational biology, and bioinformatics
leading to major influences on the understanding of biological macromolecules and the investigation of the human genome.” ..
If this new research can help stop any further loss of species this would most definately be a step in the right direction..There are vast
implications this new technology could have in treathing all kinds of biological defiscencies,we need to look beyond the labs and the ethical issues
and help ourselves improove the quality of life for ALL people..