Inheritance of acquired characters in animals: A historical overview, further evidence and mechanistic explanations

Abstract

Since the earliest days of evolutionary thought, the problem of the inheritance of acquired characters has been a central debate. Lamarck, Darwin and several of the greatest figures in the history of biology accepted the inheritance of acquired characters as an established fact, but many geneticists refused to accept its reality. Historically speaking, three epochal episodes – Weismann's Barrier, Kammerer's midwife toad and the Lysenko affair – have made this subject a heated scientific and political controversy. Over the past several decades, a substantial body of reliable experimental evidence has accumulated that environmentally induced or acquired changes in animals can be transmitted to future generations. Several well-documented examples, including diet-induced heritable changes, the inheritance of acquired habit, the inheritance of acquired immunity, the inheritance of characters acquired by blood transfusion (also known as vegetative hybridisation), the inheritance of characters acquired by a dam from her former mates (also known as telegony), are briefly reviewed in this article. There are several fundamentally different mechanisms underlying the inheritance of acquired characters and Darwin explained it only with his Pangenesis, a developmental theory of heredity. It can now be understood in terms of molecular genetics such as epigenetic inheritance, prion inheritance, RNA-mediated inheritance and horizontal gene transfer. It is now time to recognise that a new understanding of the inheritance of acquired characters opens a broader perspective on genetics and evolution.

Keywords:

• Inheritance of acquired characters
• Darwin's Pangenesis
• epigenetic inheritance
• RNA-mediated inheritance
• horizontal gene transfer

Acknowledgements

We are deeply indebted to the editor and the reviewers for their valuable comments and important suggestions.