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The reef-building coral, Acropora millepora, can pass its tolerance for heat on to the next generation via its DNA, according to a new study. This discovery suggests that some corals take advantage of an evolutionary process known as "genetic rescue," and that such species might have an easier time adapting to global warming than researchers had imagined. Groves Dixon and colleagues crossbred A. millepora corals from two locations in Australia with five degrees of latitude between them -- Princess Charlotte Bay and Orpheus Island. They exposed the corals' larvae to increasingly warm temperatures for long periods of time, and then analyzed the genes of the surviving individuals. Their results reveal that the more heat-tolerant corals from Princess Charlotte Bay produced larvae that were 10 times more likely to survive heat exposure than the larvae of the less heat-tolerant Orpheus Island corals. Furthermore, Dixon and the other researchers show that when corals from Princess Charlotte Bay cross with Orpheus Island corals, they can pass their tolerance for heat on to their offspring. The researchers identified differences in the corals' gene expression that appear to be heritable and related to heat-tolerance. Their findings suggest that corals' tolerance for temperature, which varies depending upon latitude, is passed down from generation to generation -- and that far-flung populations of coral did not simply acclimate to their different environments but instead inherited their ability to thrive in higher temperatures.
Article #14: "Genomic determinants of coral heat tolerance across latitudes," by G.B. Dixon; S.W. Davies; G.A. Aglyamova; M.V. Matz at University of Texas at Austin in Austin, TX; E. Meyer at Oregon State University in Corvallis, OR; L.K. Bay at Australian Institute of Marine Science in Townsville, QLD, Australia.