Modern Synthesis Review

The intersection of developmental biology (ontogeny) and evolutionary history (phylogeny) has long been a fertile ground for scientific inquiry. The modern synthesis, the prevailing framework for evolutionary biology, largely explains these processes through changes in gene frequencies within populations, driven by natural selection acting on heritable genetic variation.  However, the emerging field of epigenetics offers a compelling and increasingly essential perspective, suggesting that non-genetic, heritable changes in gene expression play a far more significant role in shaping both individual development and evolutionary trajectories than previously understood. The paper "Ontogeny and phylogeny from an epigenetic point of view" delves into this intricate relationship, highlighting how epigenetics fundamentally challenges the modern synthesis. Epigenetics, broadly defined, refers to heritable changes in gene function that occur without a change in the DNA sequ...

"We argue that there are compelling reasons to think that both frameworks (MS & EES) are incommensurable, thereby leaving the door open for future philosophical explorations." -Incommensurability in Evolutionary Biology: The Extended Evolutionary Synthesis Controversy Thomas Kuhn's seminal work, The Structure of Scientific Revolutions, posits that science progresses not just through gradual accumulation of knowledge, but through periodic paradigm shifts – fundamental changes in the conceptual frameworks, accepted theories, and methodologies that define a field. Applying Kuhn's lens to contemporary evolutionary biology offers a powerful framework for understanding the ongoing debates surrounding the Extended Evolutionary Synthesis (EES) and its relationship to the long-dominant paradigm of Neo-Darwinism (often termed the Modern Synthesis, MS). Central to this discussion is the burgeoning field of epigenetics, which presents phenomena that act as Kuhnian...

Epigenetic Gene Families  The field of molecular phylogeny, which reconstructs evolutionary relationships based on molecular data, has revolutionized our understanding of life's history. By analyzing DNA, RNA, and protein sequences, molecular phylogenetics has provided unprecedented insights into species diversification, ancient common ancestors, and the timing of evolutionary events. However, as our knowledge of molecular mechanisms expands, particularly in the realm of epigenetics, new complexities emerge that challenge the foundational principles of the Modern Synthesis of evolution. This essay will explore how epigenetics is intricately involved in molecular phylogeny and how its influence necessitates a significant expansion, of the traditional evolutionary framework. Molecular Phylogeny: A Brief Overview Molecular phylogeny operates on the premise that genetic sequences accumulate changes over time at a relatively constant rate. These changes, primarily mutations,...