Doctoral Dissertation Research: Small but mighty: Unraveling the evolution of convergent miniaturization within primates integrating phylogenetics and comparative genomics
Overview: A primary goal of biological anthropology is to understand the evolutionary processes behind primate and human adaptation and phenotypic diversity. Body size shifts over time may have contributed to primate diversification. adaptation to varied habitats and lifestyles. and encephalization. including in the hominin lineage. It is largely accepted that primates have followed a trend of increasing body size over time; however. size reduction (phyletic miniaturization) has convergently evolved within hominins and multiple primate clades. In nonhuman primates. extreme miniaturized phenotypes may have evolved in response to similar selective factors. yet the role of adaptation in primate convergent size reduction remains speculative. The primary goal of this proposal is to determine if miniaturized primates have evolved convergently in response to selection. To achieve this goal. we propose an integrative framework that combines trait evolution and comparative genomic analyses to test shifts in evolutionary rates tied to adaptive convergent miniaturization. Based on body mass data for 348 taxa. we will first quantify the magnitude and direction of shifts in the rate of body mass evolution across primate clades. We will then assess whether convergent evolution is mirrored at the genomic level by estimating DNA similarity across the Strepsirrhines. a clade that includes at least six independent miniaturization events and evolved a five-thousand-fold variation in body mass (including extinct taxa). Lastly. we will compare rates of molecular evolution across the genome to detect signatures of selection and use gene ontologies to characterize the biological functions of flagged loci. To achieve these goals. we will generate new whole-genome data for 12 species based on modern and historical museum samples and combine them with published data for a final dataset comprising 21 miniaturized and 27 non-miniaturized species. Intellectual merit: The recent discovery of two small-statured archaic hominins (H. floresiensis and H. luzonensis) has shown that human evolution was non-linear. intensifying discussions about adaptive size reduction in anthropology. This research project will further our understanding of primate adaptation and phenotypic diversification by identifying the evolutionary processes behind the convergent evolution of small body sizes. While it has been often assumed that miniaturized living taxa are a good model for the ancestral primate. distinct lineages may have evolved similar size through alternative genetic and physiological mechanisms. To test to what extent shared mechanisms underlie convergent phenotypes in distantly related taxa. this proposal will leverage recent advances in phylogenetic comparative methods and evolutionary genomics. This study's outcomes will contribute to our understanding of primate genetic architecture and the temporal dynamics of trait diversification. contextualizing human variation in an evolutionary framework. Broader Impacts: This multidisciplinary research strongly aligns with NSF's goal of increasing the representation of historically minoritized groups in STEM fields. Lead by a first-generation Latina scientist. this project will extend training opportunities and accessibility of students from underrepresented groups to bioinformatics at a public minority-serving institution (UTSA). New genetic data will be made publicly available. providing a valuable resource for future studies of a diversity of topics in evolutionary anthropology. Results from this project will be presented at national and international conferences and submitted for peer-review in broad audience high-impact and society journals.