In the third of a series showcasing Africa's musical talent, Moroccan singer Ahmed Soultan performs his song Ignorance.
Ahmed is a Moroccan musician who is passionate about reconnecting his country with the rest of Africa.
His music combines Arabic slang, and the melodies that characterise the music of the Middle East, with Berber beats that he says are fundamentally African.
Early on, he rejected advice that he should go to Paris to further his musical career.
Instead, he headed to Dakar, the Senegalese capital. There he connected with reggae and hip hop artists such as Tiken Jah Fakoly and Positive Black Soul.
He has released two albums to date, Tolerance in 2006 and Code in 2009. He is working on a third.
Horrific crimes, such as the Anders Breivik case, illustrate the misconceptions the public has about mental illness, a leading expert says.
Professor Simon Wessely, of King's College London, said the simplest responses to mass killings were that the perpetrators "must be mad".
But he said the way Breivik carried out the killings suggested otherwise.
He said the idea a psychiatric diagnosis could help people avoid punishment was wrong too.
Writing in the Lancet medical journal, Professor Wessely said putting forward a mental illness defence in the UK could lead a person to spending more time behind bars than less.
"The forensic psychiatry system is not a soft or popular option," he added.
'Meticulous way'
The psychiatrist also said the Breivik case highlighted another misconception - that outrageous crimes must mean mental illness.
"For schizophrenia to explain Breivik's actions, they would have to be the result of delusions."
But he added: "The meticulous way in which he planned his attacks does not speak to the disorganisation of schizophrenia."
Breivik is currently on trial in Norway.
The 33-year-old admits to killing 77 people in Oslo and on Utoeya island last July but denies criminal responsibility.
Two reports have been compiled on his mental state and have come to opposing views on his sanity.
The court's ruling on this will determine whether Breivik is sent to jail or into psychiatric care.
Breivik has argued he is not insane and should either be put to death or acquitted.
Researchers have succeeded in mimicking the chemistry of life in synthetic versions of DNA and RNA molecules.
The work shows that DNA and its chemical cousin RNA are not unique in their ability to encode information and to pass it on through heredity.
The work, reported in Science, is promising for future "synthetic biology" and biotechnology efforts.
It also hints at the idea that if life exists elsewhere, it could be bound by evolution but not by similar chemistry.
In fact, one reason to mimic the functions of DNA and RNA - which helps cells to manufacture proteins - is to determine how they came about at the dawn of life on Earth; many scientists believe that RNA arose first but was preceded by a simpler molecule that performed the same function.
However, it has remained unclear if any other molecule can participate in the same unzipping and copying processes that give DNA and RNA their ability to pass on the information they carry in the sequences of their nucleobases - the five chemical group "letters" from which the the two molecules' genetic information is composed.
There is nothing 'Goldilocks' about DNA and RNA - there is no overwhelming functional imperative for genetic systems or biology to be based on them”
Philipp HolligerMedical Research Council
The classic double-helix structure of DNA is like a twisted ladder, where the steps are made from paired nucleobases (RNA is typically a single helix).
Philipp Holliger of the UK Medical Research Council's Laboratory of Molecular Biology and a team of colleagues created six different DNA- and RNA-like molecules - xeno-nucleic acids, or XNAs - by replacing not the nucleobases but the sugar groups that make up the sides of the ladder.
"There's a lot of chemisty that seeks to build alternative nucleic acids, and people have been modifying the bases, the sugars and the backbone, but what we were focusing on was the type of nucleic acid or polymers that would retain the ability to communicate with the natural DNA," Dr Holliger explained in an interview for the Science podcast.
Because the nucleobases themselves were the same as those of DNA and RNA, the resulting molecules were able to join with their natural counterparts.
The effect is similar to work recently published in Nature Chemistry, showing that another sugar-substituted DNA analogue could be made to pair up with DNA itself.
But the crucial point in creating a full "synthetic genetics" is a set of nucleic acids like DNA and RNA that can not only carry genetic information, but would also allow it to be changed and passed on - evolution and heredity.
That requires a set of helper molecules called polymerases, which, once DNA or RNA "unzip" and expose their genetic information, help create new DNA molecules from those instructions.
The work's key advance is the "polymerase" molecules that guide the copying process
Dr Holliger and his colleagues have developed polymerases that efficiently transcribe the code of their synthetic DNA to natural DNA and then from that back to another synthetic DNA.
The process of evolution was encouraged in the lab; one of their DNA analogues was designed to cling to a particular protein or RNA target, those that failed to do so were washed away.
As successive copies of those that stuck were made, variations in the genetic code - and the resulting structure the molecules took on - led to ever more tightly attached XNAs.
"We've been able to show that both heredity - information storage and propagation - and evolution, which are really two hallmarks of life, can be reproduced and implemented in alternative polymers other than DNA and RNA," Dr Holliger explained.
"There is nothing 'Goldilocks' about DNA and RNA - there is no overwhelming functional imperative for genetic systems or biology to be based on these two nucleic acids."
In an accompanying article in Science, Gerald Joyce of the Scripps Research Institute wrote that "the work heralds the era of synthetic genetics, with implications for exobiology (life elsewhere in the Universe), biotechnology, and understanding of life itself".
But the work does not yet represent a full synthetic genetics platform, he pointed out. For that, a self-replicating system that does not require the DNA intermediary must be developed.
With that in hand, "construction of genetic systems based on alternative chemical platforms may ultimately lead to the synthesis of novel forms of life".
