A recent sequencing study has shown that two common Caribbean corals, Montastraea cavernosa and Siderastrea siderea , each consist of four genetically distinct lineages in the Florida Keys. These lineages are specialised to a certain depth and, to a lesser extent, to nearshore or offshore habitats. We hypothesised that the lineages' environmental specialisation is at least in part due to regulatory evolution, which would manif...

Coral populations across the Great Barrier Reef (GBR) could rapidly adapt to the warming climate if they have standing genetic variation for thermal tolerance. Here, we describe a locus likely involved in latitudinal adaptation of Acropora millepora . This locus shows a steep latitudinal gradient of derived allele frequency increasing at higher latitudes, and harbours a cluster of eight tandemly repeated Δ9‐desaturase genes ad...

Coral bleaching, the stress‐induced breakdown of coral‐algal symbiosis, threatens reefs globally. Paradoxically, despite adverse fitness effects, corals bleach annually, even outside of abnormal temperatures. This generally occurs shortly after the once‐per‐year mass coral spawning. Here, we propose a hypothesis linking annual coral bleaching and the transmission of symbionts to the next generation of coral hosts. We developed...

Mortality rates of marine fish larvae are incredibly high and can determine year‐class strength. The major causes of larval mortality are predation and starvation, and the performance of larvae in survival skills that can mitigate this mortality (predator evasion, foraging) varies among individuals and cohorts, but the causes of the variation are not known. Transcriptomics can link gene expression variation to phenotypic varia...

Processes governing genetic diversity and adaptive potential in reef‐building corals are of interest both for fundamental evolutionary biology and for reef conservation. Here, we investigated the possibility of “sweepstakes reproductive success” (SRS) in a broadcast spawning coral, Acropora hyacinthus , at Yap Island, Micronesia. SRS is an extreme yearly variation in the number of surviving offspring among parents. It is predi...

Ancient DNA (aDNA) has been applied to evolutionary questions across a wide variety of taxa. Here, for the first time, we utilized aDNA from millennia‐old fossil coral fragments to gain new insights into a rapidly declining western Atlantic reef ecosystem. We sampled four Acropora palmata fragments (dated 4215 BCE to 1099 CE) obtained from two Florida Keys reef cores. From these samples, we established that it is possible both...

The global impacts of climate change are evident in every marine ecosystem. On coral reefs, mass coral bleaching and mortality have emerged as ubiquitous responses to ocean warming, yet one of the greatest challenges of this epiphenomenon is linking information across scientific disciplines and spatial and temporal scales. Here we review some of the seminal and recent coral‐bleaching discoveries from an ecological, physiologic...

As sea surface temperatures increase, many coral species that used to harbour symbionts of the genus Cladocopium have become colonized with the thermally tolerant genus, Durusdinium . Here, we asked how gene expression in the symbionts of one genus changes depending on the abundance of another symbiont genus within the same coral host, and what effect this interaction has on the host. Symbiont gene expression was overwhelmingl...

Broadcast‐spawning coral species have wide geographical ranges spanning strong environmental gradients, but it is unclear how much spatially varying selection these gradients actually impose. Strong divergent selection might present a considerable barrier for demographic exchange between disparate reef habitats. We investigated whether the cross‐shelf gradient is associated with spatially varying selection in two common coral...

Many broadly‐dispersing corals acquire their algal symbionts (Symbiodiniaceae) “horizontally” from their environment upon recruitment. Horizontal transmission could promote coral fitness across diverse environments provided that corals can associate with divergent algae across their range and that these symbionts exhibit reduced dispersal potential. Here we quantified community divergence of Cladocopium algal symbionts in two...

As climate change progresses, reef‐building corals must contend more often with suboptimal conditions, motivating a need to understand coral stress response. Here, we test the hypothesis that there is a stereotyped transcriptional response that corals enact under all stressful conditions, functionally characterized by downregulation of growth, and activation of cell death, response to reactive oxygen species, immunity, and pro...

The potential of reef‐building corals to adapt to increasing sea‐surface temperatures is often debated but has rarely been comprehensively modeled on a region‐wide scale. We used individual‐based simulations to model adaptation to warming in a coral metapopulation comprising 680 reefs and representing the whole of the Central Indo‐West Pacific. Encouragingly, some reefs—most notably Vietnam, Japan, Taiwan, New Caledonia and th...

Climate change threatens organisms in a variety of interactive ways that requires simultaneous adaptation of multiple traits. Predicting evolutionary responses requires an understanding of the potential for interactions among stressors and the genetic variance and covariance among fitness‐related traits that may reinforce or constrain an adaptive response. Here we investigate the capacity of Acropora millepora , a reef‐buildin...

Identifying which factors lead to coral bleaching resistance is a priority given the global decline of coral reefs with ocean warming. During the second year of back‐to‐back bleaching events in the Florida Keys in 2014 and 2015, we characterized key environmental and biological factors associated with bleaching resilience in the threatened reef‐building coral Orbicella faveolata . Ten reefs (five inshore, five offshore, 179 co...

Reef‐building corals can increase their resistance to heat‐induced bleaching through adaptation and acclimatization and/or by associating with a more thermo‐tolerant strain of algal symbiont ( Symbiodinium sp.). Here, we show that these two adaptive pathways interact. We collected Acropora millepora corals from two contrasting thermal environments on the Great Barrier Reef: cooler, mid‐latitude Orpheus Island, where all corals...

Adaptive variation in social behaviour depends upon standing genetic variation, but we know little about how evolutionary forces shape genetic diversity relevant to brain and behaviour. In prairie voles ( Microtus ochrogaster) , variants at the Avpr1a locus predict expression of the vasopressin 1a receptor in the retrosplenial cortex (RSC), a brain region that mediates spatial and contextual memory; cortical V1aR abundance in...

On one night per year, at a specific point in the lunar cycle, one of the most extraordinary reproductive events on the planet unfolds as hundreds of millions of broadcast spawning corals release their trillions of gametes into the waters of the tropical seas. Each species spawns on a specific night within the lunar cycle, typically from full moon to third quarter moon, and in a specific time window after sunset. This accuracy...

Effective dispersal across environmental gradients is the key to species resilience to environmental perturbation, including climate change. Coral reefs are among the most sensitive ecosystems to global warming, but factors predicting coral dispersal potential remain unknown. In a reef‐building coral Acropora millepora , larval fluorescence emerged as a possible indicator of dispersal potential since it correlates with respons...

Despite decades of monitoring global reef decline, we are still largely unable to explain patterns of reef deterioration at local scales, which precludes the development of effective management strategies. Offshore reefs of the Florida Keys, USA, experience milder temperatures and lower nutrient loads in comparison to inshore reefs yet remain considerably more degraded than nearshore patch reefs. A year‐long reciprocal transpl...

We are writing in response to the population and phylogenomics meeting review by Andrews & Luikart ( ) entitled ‘Recent novel approaches for population genomics data analysis’. Restriction‐site‐associated DNA ( RAD ) sequencing has become a powerful and useful approach in molecular ecology, with several different published methods now available to molecular ecologists, none of which can be considered the best option in all sit...