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Whilst previous outbreaks of Ebola were confined to central Africa, the 2014 outbreak began in the west African nation of Guinea, and has spread to Sierra Leone, Liberia and Nigeria. Now, researchers have sequenced 99 Ebola virus genomes from patients in West Africa, the site of the recent and largest outbreak ever recorded. Stephen Gire of Harvard University discusses new insights into how and when Ebola entered human populations in the 2014 outbreak.

Lake Urmia
Lake Urmia in Iran's west Azerbaijan is the world's second largest salt water lake on Earth, home to 212 species of birds, 41 reptiles, seven amphibians and 27 mammals. Experts have warned that ecological factors and human activity will lead to the drying up of Lake Urmia in the near future. Naser Agh, biologist at Urmia University and Professor Kathleen Nicoll discuss the repercussions.

Early Galaxies
Upcoming missions are planned to map and measure galaxy formation in the Universe in unprecedented detail. DESI - the Dark Energy Spectroscopic Instrument, due to start in 2018 - is designed to measure how Dark Energy could be fuelling the expansion of the Universe, but what it sees will also give us new detail about how evenly the cosmos is illuminated. To do this, cosmologists including Dr Andrew Pontzen at University College London have developed a new method.

Malleable Memories
Researchers from MIT have reversed the emotional association of specific memories in mice. The scientists used genetically engineered mice with fibre optic brain implants – a field known as optogenetics. They can now change the way those mice feel about a place. Â鶹ԼÅÄ Science reporter Jonathan Webb tells us more, along with Professor Richard Morris from the University of Edinburgh.

(Photo: In a handout from the Center for Disease Control, a colorized transmission electron micrograph (TEM) of a Ebola virus virion is seen © Center for Disease Control/Getty Images)

Presenter: Jack Stewart
Producer: Adrian Washbourne