{"id":3067,"date":"2011-10-10T09:11:22","date_gmt":"2011-10-09T22:11:22","guid":{"rendered":"https:\/\/scienceillustrated.com.au\/blog\/?p=3067"},"modified":"2012-03-21T09:29:19","modified_gmt":"2012-03-20T22:29:19","slug":"lungfish-provide-insight-into-terrestrial-evolution","status":"publish","type":"post","link":"https:\/\/scienceillustrated.com.au\/blog\/nature\/lungfish-provide-insight-into-terrestrial-evolution\/","title":{"rendered":"Lungfish provide insight into terrestrial evolution"},"content":{"rendered":"
\"\"<\/p>\n

The larvae of one of the Australia's lungfish species. Photo credit: Nicholas J Cole<\/p>\n<\/div>\n

Australia’s living fossil has given scientists an insight into the development of our hind legs.<\/strong><\/p>\n

Ancient lungfish are the ancestors of the tetrapods, the four-legged creatures that took the first steps on land 400 million years ago. These fish could breathe air and propel themselves along the ground with their fins, allowing them to survive on land.<\/p>\n

Australia is home to two marine species of lungfish and a third that inhabits Queensland’s Mary River Basin. A team of scientists led by Professor Peter Currie, from the Australian Regenerative Medicine Institute<\/a> at Monash University, and Dr Nicolas Cole, from the University of Sydney<\/a>, used these living fossils to trace the evolution of terrestrial hind legs.<\/p>\n

“Lung fish are the closest living fish species to tetrapods,”\u009d said Professor Currie, one of the authors of the study published in the online journal PLoS<\/a>.<\/p>\n

Most of our understanding of tetrapod transition comes from the fossil record, according to Professor Currie. But the fossil record rarely preserves soft tissues, such as muscles, so the scientists needed to examine living specimens.<\/p>\n

The scientists compared embryos of the lungfish and two additional bony fish species- the zebra fish and the American paddlefish. These are descendants of primitive species which represent key points in vertebrate evolution to see if there were differences in pelvic fin muscle formation.<\/p>\n

They also examined two primitive shark species- the elephant shark and the bamboo shark, which represent another, earlier point in vertebrate evolution. “In order to examine the evolution of different mechanisms we need to know what they evolved from,”\u009d Professor Currie said.<\/p>\n

“The statements about the intermediate nature of fin muscle formation in bony fish, including lungfish, could not be made if we did not examine chimera and sharks, which have the primitive mechanism.”\u009d<\/p>\n

Using the embryos, the scientists genetically engineered the fish and traced the migration of early muscle cells during the course of development of the different species. This enabled them to examine how the different genes required for making muscle of the fins are activated during the process of fin\/limb muscle formation.<\/p>\n

“Specific genes are used in different modes of muscle formation, so how the genes are expressed can tell us the mechanism is utilised in different fish to make fin muscle,”\u009d Professor Currie said. “Also the different mechanisms can be distinguished by simple histology of the different fish species at specific points in development.”\u009d<\/p>\n

The results showed that the bony fish had a different mechanism of pelvic fin muscle formation from that of the shark species. This mechanism was a transitional stepping stone between the sharks’ fins and the hind limbs of our tetrapod ancestors.<\/p>\n","protected":false},"excerpt":{"rendered":"

Australia’s living fossil has given scientists an insight into the development of our hind legs.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,64,88,32,6,49,8],"tags":[],"class_list":["post-3067","post","type-post","status-publish","format-standard","hentry","category-animals","category-ecology","category-genetics","category-marine-biology","category-nature","category-palaeontology","category-science"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/3067"}],"collection":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/comments?post=3067"}],"version-history":[{"count":4,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/3067\/revisions"}],"predecessor-version":[{"id":3102,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/3067\/revisions\/3102"}],"wp:attachment":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/media?parent=3067"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/categories?post=3067"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/tags?post=3067"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}