NSF PRFB FY 2023: Investigating proximate mechanisms and ultimate drivers of temperature-dependent development of male:female ratios in reptiles

这项行动资助了2023财年的NSF生物学博士后研究奖学金，综合研究调查了基因组，环境和表型之间的生命管理相互作用的规则。该研究金支持研究员的研究和培训，以创新的方式为生活规则领域做出贡献。在许多爬行动物中，个体发育为雄性还是雌性取决于它们在卵内发育时所经历的温度。了解这一过程的生物机制越来越紧迫，因为气候变暖可能会在个人和群体层面影响这些过程。尽管自20世纪60年代以来一直在研究这种发育系统，但我们仍然对温度如何影响这种发育和这些物种的生存知之甚少。目前尚不清楚1）相同的温度如何在不同的物种中产生相反的结果，以及2）在卵中发育时所经历的温度如何影响生存的概率。这项研究将直接促进我们对雄性和雌性爬行动物发育机制的理解，并将为针对脆弱种群和物种的保护工作提供信息。该研究员将接受基因组技术和建模方面的培训，并将通过向经济落后地区的当地学校介绍研究来扩大科学参与。雌性或雄性表型的温度依赖性代表了发育可塑性的直接情况，其中在离散发育窗口期间经历的温度决定了这种发育。而类似的热线索的分子和遗传反应似乎是保守的，由此产生的发育结果不同物种。例如，低温会导致红耳滑龟（Trachemys scripta）和美洲短吻鳄（Alligator mississippiensis）中保守的染色质修饰物的上调，但这些温度会使T. scripta和A.密西西比河。本研究的第一个目标将使用ChIP-seq和ATAC-seq方法来检验染色质修饰剂与海龟和鳄鱼基因组中不同遗传位点相互作用以产生物种特异性反应规范的假设。其次，最近的理论和经验数据支持的想法，孵化温度介导的影响男性与女性的生存成熟的适应价值的发展可塑性的基础。在孵育A.密西西比鳄卵在实验室中不同波动的温度代表未来变暖的情景，这项研究的第二个目标是解决日益温暖的气候将如何影响鳄鱼雄性：女性比例，伴随的人口结构，以及，最终这个温度的适应值-该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的评估支持知识价值和更广泛的影响审查标准。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2023, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment, and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. In many reptiles, whether an individual develops as a male or a female depends upon the temperatures that they experienced while developing inside the egg. There is increased urgency to understand the biological mechanisms of this process, as a warming climate will likely influence these processes at both individual and population levels. Even though this developmental system has been studied since the 1960s, we still know very little about how exactly temperature influences this development and the survival of these species. It remains unknown 1) how the same temperature produces opposite outcomes across different species and 2) how temperatures experienced while developing in the egg affect the probability of survival. This research will directly advance our understanding of mechanisms regulating the development of male and female reptiles and will inform conservation efforts aimed at vulnerable populations and species. The fellow will be trained in genomic techniques and modeling and will also broaden participation in science by presenting the research to local schools in an economically disadvantaged area. The temperature-dependence of female or male phenotype represents a straightforward case of developmental plasticity, in which the temperature experienced during discrete developmental windows dictates this development. Whereas the molecular and genetic responses to similar thermal cues appear to be conserved, the resultant developmental outcomes vary across species. For example, cool temperatures lead to the upregulation of conserved chromatin modifiers in the red-eared slider turtle (Trachemys scripta) and the American Alligator (Alligator mississippiensis), but these temperatures produce males in T. scripta and females in A. mississippiensis. The first objective of this research will use ChIP-seq and ATAC-seq approaches to test the hypothesis that chromatin modifiers interact with different genetic loci across the turtle and crocodilian genome to produce species-specific reaction norms. Second, recent theoretical and empirical data support the idea that incubation temperature-mediated effects on male vs female survival to maturity underlie the adaptive value of developmental plasticity. Using recapture efforts after incubating A. mississippiensis eggs in the lab at different fluctuating temperatures representing future warming scenarios, the second objective of this research is aimed at addressing how increasingly warm climates will affect crocodilian male: female ratios, attendant population structures, and, ultimately the adaptive value of this temperature-dependent developmental plasticity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.