For over sixty years it has been widely accepted that twinning, the process that results in identical or conjoined twins, normally occurs about two weeks after fertilization, or conception. This ...

Early sea urchin embryos can be split into two, and each half can develop into a complete individual. In other words, they can produce identical (monozygotic) twins—a phenomenon known as regulative ...

The Nature Index 2024 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...