lost adaptive immunity<\/a> could one day contribute to advances in medical procedures, such as organ transplants and skin grafting.<\/p>\nUsing genetic data from the genomes of anglerfishes, the researchers showed how complex features\u2014such as sexual parasitism\u2014assisted some anglerfish groups in transitioning from roaming shallow habitats, such as coral reefs, to swimming in the dark, open waters of the “midnight zone,” the deep-sea ecosystem where sunlight cannot penetrate.<\/p>\n
“People tend to have single-trait explanations for why a group of animals can thrive in a given ecosystem, but in most living things, it seems that several distinctive innovations work synergistically to exploit new habitats,” says Chase D. Brownstein, a graduate student in Yale’s ecology and evolutionary biology department and the study’s co-lead author.<\/p>\n
“We found that a cascade of traits, including those required for sexual parasitism, allowed anglerfishes to invade the deep sea during a period of extreme global warming when the planet’s oceans where in ecological upheaval.”<\/p>\n
For the study, the researchers reconstructed the evolutionary history of the deep-sea species. They demonstrated that the rapid transition of ceratioid anglerfishes from benthic walkers, which use modified fins to “walk” the ocean floor in the shallows, to deep-sea swimmers occurred 50 to 35 million years ago during the Paleocene-Eocene Thermal Maximum, a period of high global temperatures that induced extinction throughout the oceans.<\/p>\n
Ultimately, the researchers were unable to infer a clear evolutionary tree for deep-sea anglerfishes because the various lineages diverged from each other so rapidly, leaving relationships among lineages unresolvable, Brownstein says. But they found that the origins of sexual parasitism coincided with anglerfishes’ transition to the deep sea, although they could not determine which of the two forms of parasitism\u2014temporary attachment or obligate parasitism\u2014first occurred, Brownstein says.<\/p>\n
Multiple traits evolved simultaneously to enable sexual parasitism. For example, ceratioids needed to evolve extreme sexual dimorphism with large females and miniature males. They also needed to shed their adaptive immunity\u2014the system of specialized immune cells and antibodies that attack and eliminate pathogens\u2014so that the female hosts’ bodies do not reject the parasitic male.<\/p>\n
By reconstructing the evolutionary history of key genes involved in adaptive immunity, the researchers learned that multiple groups of deep-sea anglerfishes convergently degenerated their adaptive immunity, enabling sexual parasitism. And although sexual parasitism was evolving as deep-sea anglerfishes moved into the deep sea, they concluded that it is not necessarily the key trait driving species diversification among ceratioids. However, it did enable anglerfish to succeed in the midnight zone, Brownstein says.<\/p>\n
“Sexual parasitism is thought to be advantageous to inhabiting the deep sea, which is Earth’s largest and most homogenous habitat,” he says. “Once individuals find a mate in that vast expanse, obligate sexual parasitism allows them to permanently latch, which seems to be a critical aid to the evolution of deep-sea anglerfish.”<\/p>\n
The research has potential implications on human health, says senior author Thomas Near, professor of ecology and evolutionary biology at Yale and Bingham Oceanographic Curator of Vertebrates at the Yale Peabody Museum.<\/p>\n
“Better understanding how deep-sea anglerfishes lost adaptive immunity could one day contribute to advances in medical procedures, such as organ transplants and skin grafting, where suppressing immunity is crucially important,” he says. “It’s an interesting area for future medical research.”<\/p>\n
Additional coauthors are from the University of North Carolina at Charlotte; Yale; the US Department of Natural Resources, Marine Resources Division; and the University of Chicago.<\/p>\n
Source: Yale University<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"A new study illuminates the evolution of deep-sea anglerfish with a focus on the development […]<\/p>\n","protected":false},"author":6412,"featured_media":3223452,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[3],"tags":[119,229,286],"class_list":["post-3223442","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science-technology","tag-evolution","tag-fish","tag-mating","university-yale-university"],"acf":[],"yoast_head":"\n
Study sheds light on anglerfish's weird mating routine - 糖心视频<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n \n \n \n \n \n\t \n\t \n\t \n