Sexual dimorphism, i.e., differences in morphology, physiology, and behavior between conspecific males and females, is ubiquitous, extensive, and often species-specific, indicative of its rapidly evolving nature. Ever since Darwin first described a general theory of sexual selection to explain the extraordinary differences between males and females of the same species, biologists have proposed a variety of mechanisms ranging from runaway selection to good genes to sexual conflict. While a popular approach is studying the effects of sexual selection on different components of fitness, the results of these studies are generally difficult to interpret and are typically not generalizable across populations, let alone taxa. Recent advances in the "omics" field are transforming the way that we study patterns and processes involved in sexual selection. At the molecular level, sexual dimorphism is present in gene expression differences between the sexes, providing a powerful framework to study sexual selection. By studying genes that are sex-biased in expression, we will better understand the underlying genetic basis of traits that are sexually dimorphic. Alreadly, studies of sex-biased genes in model organisms, particularly Drosophila, have revealed that male-biased genes are among the most rapidly evolving functional classes of genes. However, while a number of intrinsic factors appear to correlate with evolutionary rate (e.g., gene expression level, codon bias), it is unclear whether any of these factors drive the rapid divergence of male-biased genes. Another important discovery is the prevalence of sex-biased gene expression. However, even with widespread sexual dimorphism at the phenotypic level, it remains unknown the extent to which sex-biased gene expression exists in humans and their primate relatives. In fact, studies of sexual dimorphism on a molecular level in primates have been very few, even though understanding this phenomenon in humans could further our knowledge of the nature of sex-biased phenotypes and diseases. In this thesis, I advance our knowledge of the genetic bases and mechanisms that shape sexual dimorphism. First, I review a classic framework that biologists have traditionally applied to define and partition fitness measures between males and females in the model system, Drosophila. Second, I apply a molecular framework to compare the relative roles of intrinsic factors on the evolutionary rate of rapidly evolving male-biased genes in Drosophila. Third, I review the current state of our knowledge of sexual dimorphism and sex-biased gene expression in humans. Fourth, I present a bioinformatics framework to identify the extent of sex-biased expression in primate tissue and to examine the selective forces involved in their evolution. Overall, I demonstrate the effectiveness of using a functional comparative genomics approach in studying the nature of sexual dimorphism at the molecular level across multiple taxa.

Sexual Selection in Primates is a comprehensive summary of primate sexual interactions.

The Primate Origins of Human Nature (Volume 3 in The Foundations of Human Biology series) blends several elements from evolutionary biology as applied to primate behavioral ecology and primate psychology, classical physical anthropology and evolutionary psychology of humans. However, unlike similar books, it strives to define the human species relative to our living and extinct relatives, and thus highlights uniquely derived human features. The book features a truly multi-disciplinary, multi-theory, and comparative species approach to subjects not usually presented in textbooks focused on humans, such as the evolution of culture, life history, parenting, and social organization.

For many years, experiments using chimpanzees have been instrumental in advancing scientific knowledge and have led to new medicines to prevent life-threatening and debilitating diseases. However, recent advances in alternate research tools have rendered chimpanzees largely unnecessary as research subjects. The Institute of Medicine, in collaboration with the National Research Council, conducted an in-depth analysis of the scientific necessity for chimpanzees in NIH-funded biomedical and behavioral research. The committee concludes that while the chimpanzee has been a valuable animal model in the past, most current biomedical research use of chimpanzees is not necessary, though noted that it is impossible to predict whether research on emerging or new diseases may necessitate chimpanzees in the future.

This breakthrough book brings science into history to offer a dazzling new vision of humanity across time. Team-written by leading experts in a variety of fields, it maps events, cultures, and eras across millions of years to present a new scale for understanding the human body, energy and ecosystems, language, food, kinship, migration, and more.