Scientists said they had made the long-sought discovery of how sperm latches onto an egg in the very first spark of reproduction, the outcome of a near decade-long hunt.

The find opens up avenues for new contraception or treating infertility, they said.

When a sperm meets an egg, they fuse to form a single-cell entity called a zygote, which divides to produce an embryo.

In 2005, Japanese researchers reported they had found a molecule jutting from the membrane of mammalian sperm that docks onto the surface of the egg.

They called it Izumo, after a Japanese marriage shrine.

That unleashed the search for the receptor on the surface of the egg, which has been elusive, until now.

Reporting in the journal Nature, researchers at Britain’s Wellcome Trust Sanger Institute said the mechanism is contained in a protein on the egg’s membrane, under a thin external coat called the zona pellucida.

The protein has been dubbed Juno, after the Roman goddess of fertility and marriage.

‘We have solved a long-standing mystery in biology by identifying the molecules displayed on all sperm and egg,” said lead researcher Gavin Wright.

‘Without this essential interaction, fertilization just cannot happen. We may be able to use this discovery to improve fertility treatments and develop […]