Multiyear trend in reproduction underpins interannual variation in gametogenic development of an Antarctic urchin.

Ecosystems and their biota operate on cyclic rhythms, often entrained by predictable, small-scale changes in their natural environment. Recording and understanding these rhythms can detangle the effect of human induced shifts in the climate state from natural fluctuations. In this study, we assess long-term patterns of reproductive investment in the Antarctic sea urchin, Sterechinus neumayeri, in relation to changes in the environment to identify drivers of reproductive processes. Polar marine biota are sensitive to small changes in their environment and so serve as a barometer whose responses likely mirror effects that will be seen on a wider global scale in future climate change scenarios. Our results indicate that seasonal reproductive periodicity in the urchin is underpinned by a multiyear trend in reproductive investment beyond and in addition to, the previously reported 18–24 month gametogenic cycle. Our model provides evidence that annual reproductive investment could be regulated by an endogenous rhythm since environmental factors only accounted for a small proportion of the residual variation in gonad index. This research highlights a need for multiyear datasets and the combination of biological time series data with large-scale climate metrics that encapsulate multi-factorial climate state shifts, rather than using single explanatory variables to inform changes in biological processes

Functional thermal limits are determined by rate of warming during simulated marine heatwaves

Marine heatwaves (MHWs) are increasing in both intensity and frequency against a backdrop of gradual warming associated with climate change. In the context of MHWs, animals are likely to experience sub-lethal, rather than lethal effects, defining long-term limits to survival and/or impacting individual and population fitness. This study investigated how functional sub-lethal limits track critical thresholds and how this relationship changes with warming rate. To this end we monitored basic functioning, specifically the ability to right, feed and assimilate energy, as well as oxygen consumption rate in the common Antarctic sea urchin, Sterechinus neumayeri. Water temperature in experimental systems was increased at rates of 1oC day-1, 0.5oC day-1 and 0.3oC day-1, in line with the characteristics of MHW events previously experienced at the site where the study urchins were collected on the Antarctica Peninsula. Functioning was assessed during the simulation of MHWs and sub-lethal limits determined when the rate of functional degradation changed as temperature increased. Results suggest that thermal sensitivity varies between the key biological functions measured, with the ability to right having the highest thermal threshold. Arguably, the most interesting result was that functions deteriorated at lower temperatures when warming was more rapid (1oC day-1), contrary to lethal critical thresholds, which were reached at lower temperatures when warming was slower (0.3oC day-1). MHWs and their impacts extend far beyond Antarctica and in this context, our analyses indicate that the onset rate of MHWs is critical in determining an organism’s ability to tolerate short-term elevated temperatures

Rare and low-frequency coding variants alter human adult height

Height is a highly heritable, classic polygenic trait with ~700 common associated variants identified so far through genome - wide association studies . Here , we report 83 height - associated coding variants with lower minor allele frequenc ies ( range of 0.1 - 4.8% ) and effects of up to 2 16 cm /allele ( e.g. in IHH , STC2 , AR and CRISPLD2 ) , >10 times the average effect of common variants . In functional follow - up studies, rare height - increasing alleles of STC2 (+1 - 2 cm/allele) compromise d proteolytic inhibition of PAPP - A and increased cleavage of IGFBP - 4 in vitro , resulting in higher bioavailability of insulin - like growth factors . The se 83 height - associated variants overlap genes mutated in monogenic growth disorders and highlight new biological candidates ( e.g. ADAMTS3, IL11RA, NOX4 ) and pathways ( e.g . proteoglycan/ glycosaminoglycan synthesis ) involved in growth . Our results demonstrate that sufficiently large sample sizes can uncover rare and low - frequency variants of moderate to large effect associated with polygenic human phenotypes , and that these variants implicate relevant genes and pathways

Functional response of the antarctic sea urchin, sterechinus neumayeri, to environmental change and extreme events in the context of a warming climate

Gradual increases in mean ocean temperature are one of many broad-scale changes currently experienced in marine systems in response to anthropogenic forcing. Extreme climate events, such as marine heatwaves are forecast to escalate in many areas of the climate system under future global change scenarios. Species will have varying capacities to adapt, persist, and ultimately survive under these scenarios of environmental change. The allocation of energy to fundamental biological functions, in addition to the ability to acclimate to gradual change and recover from acute change, is key to this capacity. In the context of the current climate and that of the future, a better understanding of how organisms allocate energy as a response to environmental drivers is needed.In this thesis I focus on the common Antarctic sea urchin, Sterechinus neumayeri; a representative species for studying environmental change impacts due to its inherent thermal sensitivity and overall significance as one of the most functionally important Antarctic shallow marine species and the most dominant echinoid in the nearshore benthic community. I explore how S. neumayeri allocates energy, in terms of reproductive investment and key biological functions, in the current climate, as well as during temperature extremes and for the climate predicted for 2100. I use a combination of approaches, including a timeseries of field-based observations and laboratory-based mesocosm experiments to simulate both gradual and acute extreme warming. My results show for the first time that endogenous rhythms against a backdrop of multifactorial shifts in the environment are key drivers of energy allocation in terms of reproduction. In addition, I show that the onset rate of acute warming is more important than absolute temperature in limiting key biological functions, and I provide evidence that a thermally sensitive species like S. neumayeri may have an improved ability to cope with acute warming following acclimation to gradual temperature increases predicted for 2100.Collectively, these results show that within the boundaries of natural variability, it is likely that species have the energetic capacity to buffer and cope with changes to the environment. However, as our global climate changes over the coming decades, the natural variability range of regional temperatures will shift in conjunction with extreme events, and as such, energetic investment and functional performance will depend on a matrix of factors such as warming onset rate and thermal history. Clearly, even some of the most thermally constrained species have the capacity to acclimate and recover from thermal stress, and although there will always be an energetic cost to this, the ability to acclimate and recover will undoubtedly benefit those who have this capacity in the future.<br/

Rare and low-frequency coding variants alter human adult height

Height is a highly heritable, classic polygenic trait with approximately 700 common associated variants identified through genome-wide association studies so far. Here, we report 83 height-associated coding variants with lower minor-allele frequencies (in the range of 0.1-4.8%) and effects of up to 2 centimetres per allele (such as those in IHH, STC2, AR and CRISPLD2), greater than ten times the average effect of common variants. In functional follow-up studies, rare height-increasing alleles of STC2 (giving an increase of 1-2 centimetres per allele) compromised proteolytic inhibition of PAPP-A and increased cleavage of