Conventional wisdom has it that Darwin’s theory of natural selection needed Mendel’s theory of inheritance to become workable, and relatedly, that had Darwin read Mendel’s 1866 paper on his experiments with crossbred peas, the necessary fix would have come around 1870 rather than decades later. This chapter shows that, on closer inspection, neither of these propositions should be accepted. From Darwin’s perspective, when it came to inheritance, his theory depended only on an undoubted fact: that offspring on the whole inherit their parents’ characters. Even when a character gets transmitted in a diluted form, due to blending, the struggle for existence ensures, as Darwin saw it, that such dilution is minimal, since only organisms that vary in similarly advantageous directions will live long enough to reproduce. Against the idea that Darwin would have instantly embraced Mendel’s paper as putting inheritance on a new, theory-saving basis, thus saving evolutionary biology from decades of sterile debate, the chapter emphasizes three points: first, the similarity between Mendel’s results and ones that Darwin was already familiar with from his own snapdragon crosses; second, the differences between Mendel’s results and ones reported in 1866 by Darwin’s pea expert, Thomas Laxton; and third, Mendel’s criticisms of Darwin on whether, as Darwin believed, variation under domestication is much greater in extent than variation in the wild.

Scientists have long recognized the value of developing methods to induce modifications in DNA sequences. Although the wave of recent breakthroughs concerning gene editing has propelled the field to the forefront of science, the concept itself is not new. This chapter explains how genome editing became a reality and argues that the concept of genetic manipulation is rooted in popular culture. The chapter begins by introducing readers to Gregor Mendel’s groundbreaking pea-plant experiments in the mid-1800s, which gave rise to modern genetics. The chapter then provides a concise overview of the origins of the concept of genetic manipulation, and how the discovery of two critical elements—restriction enzymes and DNA-repair mechanisms—in the second half of the twentieth century marked the genesis of modern molecular biology and biotechnology. Importantly, this chapter acquaints readers with fundamental concepts in molecular biology and genetics—including gene expression, DNA replication, RNA transcription, protein translation, DNA repair, the structure of DNA, the rise of genetic mutations, the flow of genetic information through the central dogma of molecular biology, and more—and explains important scientific terminology in a clear and accessible format with the aid of illustrations.