In Nature this week: Icelandic genome sequences, approach to increase CRISPR efficiency, and more.

Testing showing "genetic incompatibilities" have led thousands of couples in Saudi Arabia to call off their weddings, the BBC reports.

Decode Genetics' ability to tell Icelanders, even ones the company hasn't sequenced, about their disease risk brings up ethical questions.

Genetic analysis of Britain's King Richard III and modern descendants of his relatives indicate breaks in the male line.