Summary
"Mutants: On Genetic Variety and the Human Body" embarks on a fascinating journey into the realm of human genetics, exploring the causes and consequences of genetic mutations and their impact on the human form. It examines the human body's construction, detailing the intricate processes that transform a single cell into a complex organism. The book emphasizes that genetics, though a powerful language, remains largely unintelligible, with much of the human genome still a mystery.
The book dives into historical accounts of teratology, from the Monster of Ravenna to the collections of Willem Vrolik, illustrating how perceptions of deformity have evolved from divine punishment to scientific inquiry. It details key experiments, including Spemann and Mangold's discovery of the 'organiser' in newt embryos and the identification of sonic hedgehog as a crucial morphogen, to reveal the fundamental principles of embryonic development.
"Mutants" scrutinizes specific mutations and their effects, such as those causing sirenomelia and cyclopia, linking these conditions to failures in midline development and morphogen signalling. It also explores the role of Hox genes in determining body structure and the implications of their disruption. The role of hormones, such as growth hormone, testosterone and estrogen, are explored in the context of dwarfism, gigantism and gender development.
Further enriching the study with discussion of evolution, the book explores the influence of genetics on human traits such as skin color, height, and facial features. It sheds light on the genetic basis of various conditions, such as albinism and hypertrichosis, and the societal implications of these genetic variations. Through these explorations, "Mutants" presents a compelling narrative that not only educates but also challenges preconceived notions about genetic differences and human identity.
The book discusses the evolutionary theories of ageing, including the role of late-acting mutations, the trade-offs between reproduction and longevity, and the free radical theory. Drawing on examples from diverse species, it offers insights into the complex genetic and environmental factors that contribute to the ageing process. By weaving together science, history, and philosophical inquiry, Leroi's narrative invites readers to ponder the profound questions surrounding human existence and the intricate interplay between genes, environment, and fate.