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Y Chromosome
We learn from a young age that if a fertilised egg carries XX chromosomes it will be a girl, but with XY it will be a boy. This male Y sex chromosome has lost many genes along its evolution over the past 180 million years and now only about 20 genes remain. Two new studies published in Nature journal have given clues into how the Y chromosome evolved into its current state. Professor Henrik Kaessmann from the University of Lausanne in Switzerland explains that the genes that remain play a more important role than previously believed.

Mystery of 'Ocean Quack Sound' Solved
The mystery of a bizarre quacking sound heard in the ocean has finally been solved, scientists report. The noise - nicknamed 'the bio-duck' - appears in the winter and spring in the Southern Ocean. However, its source has baffled researchers for decades. Now acoustic recorders have revealed that the sound is in fact the underwater chatter of the Antarctic minke whale.

Everest Avalanche
Last week the biggest single loss-of-life event occurred on Everest: a huge avalanche killed 16 Sherpa guides. All were so-called "icefall doctors", possibly the riskiest job of all, which involves finding a route through the broken mass of icefall, and then securing ladders and ropes for mountaineer tourists to follow. The Himalayan Sherpas have abandoned the climbing season out of respect for the fallen. There are many questions about health and safety, but we want to know what could be done to help? ÃÛÑ¿´«Ã½ Science Reporter Victoria Gill has been looking at the science behind avalanches, Are avalanches predictable? And will global warming in the Himalayan region make them more common?

Whatever Happened to Biofuels?
Biofuels were hailed as the environmental solution to fossil fuels not that long ago. Made from living crops they take up carbon dioxide as they grow. So burning them shouldn’t disturb the balance of warming gases in the atmosphere. But for the last few years the publicity about biofuels has been mainly negative. And for good reason – biofuels are made from crops such as oil palm - grown in place of food crops or even rainforests. In some cases using these crops actually produces more CO2 than burning fossil fuels. However research is being done into new kinds of biofuels that aren’t in competition with food crops.

Drones to save Rhinos
In South Africa where robbers this week stole what may be the biggest ever haul of rhino horn. The horns had been confiscated from poachers by rangers Mpumalanga park and kept in steel safes. But the thieves succeeded in cutting through the steel and took up to 40 horns, with a black market value of 5 million dollars. With the demand for illegal horn so strong, policing South Africa’s national parks is a dangerous and difficult job, which is why Dutch aero-engineering student Kitso Epema is adapting pilotless drone aircraft to assist the park rangers in their work

French King Louis DNA
A sample of blood long thought to belong to French King Louis XVI is probably not authentic. An elaborately decorated gourd was thought to contain a handkerchief that had been dipped in the king's blood after he was killed by guillotine by French revolutionaries in 1793. But scientists have now sequenced the genome of the sample and say it is unlikely to belong to the monarch. The study is published in the journal Scientific Reports.

Testosterone Treatment
There’s been a recent rise in the number of men taking testosterone – most marked in America but happening in the UK too. In the US testosterone supplementation is being aggressively marketed at middle aged men in TV ads that highlight the symptoms of so called Low T.

Anxiety
Anxiety is a condition that can take over a person’s life, preventing them from going out, from working, even from sleeping. It is a condition thought to affect about one in 14 people around the world at any given moment and the effects can be profound. Some people experiencing anxiety – like Scott Stossel, the editor of the American magazine The Atlantic, manage to keep it secret from their friends and colleagues. But his anxiety became so serious that he nearly missed his own wedding. As an author he found publicity tours for his books so stressful that he decided to make anxiety the topic of his next - The Age of Anxiety, which of course has unfortunately resulted in another book tour.