Forming a unique part of the animal kingdom, corals have built the only living entity visible from space; the Great Barrier Reef. Scientists from the Australian Institute of Marine Science (AIMS) have recently discovered a previously unknown reproductive strategy in corals, adding another dimension to our understanding of their complex life cycles.
A study published today in the prestigious international journal Science shows for the first time that coral offspring have the unique ability to form genetic clones of themselves before they settle and develop into adult corals.
Coral 'offspring' are usually the result of sexual reproduction - eggs are fertilised either before or after being released by the parent coral into the surrounding water. These fertilised eggs are carried by ocean currents before settling at new locations.
Coral "clones", on the other hand, are genetic replicas of the parent coral. For example, if waves generated in a storm break up a coral colony, the remnant parts may continue to survive as independent but genetically identical individuals; a faculty that most animals do not possess.
Dr Andrew Heyward and Dr Andrew Negri suspected that fertilised coral eggs (embryos) might also break up because, unlike most animal embryos, coral embryos lack a protective outer-layer or membrane; they are so called 'naked' embryos.
"As the early stage embryo develops it divides into a cluster of cells," explains Dr Heyward, "because this ball of cells lacks a protective outer-layer we wondered whether subjecting them to a little turbulence might cause them break up."
It did, but what happened next was even more astonishing.
"To our surprise many of the fragmented coral embryos later began to develop and settle in just the same way as their siblings that had remained intact," continues Dr Heyward. "Interestingly, these fragmented embryos became smaller versions of baby corals than the complete
|Contact: Wendy Ellery|
Australian Institute of Marine Science