Bob Sheehy: Lead Editor

All Articles Within Evolutionary Genetics (19)

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Genome Evolution (1)

• Origins of New Genes and Pseudogenes
  The formation of new genes is a primary driving force of evolution in all organisms. How exactly do these new genes crop up in an organism’s genome and what must occur in order for them to be passed on?

Macroevolution (1)

• The Molecular Clock and Estimating Species Divergence
  What is the molecular clock? Levels of molecular variation could be used, in principle, to estimate divergence times, serving as evolutionary “clocks” that “tick” at different rates.

Microevolution (7)

• Sexual Reproduction and the Evolution of Sex
  Birds do it, and bees do it. Indeed, researchers estimate that over 99.9% of eukaryotes reproduce sexually. What, then, are the true costs and benefits of sex?
• Neutral Theory: The Null Hypothesis of Molecular Evolution
  In the decades since its introduction, the neutral theory of evolution has become central to the study of evolution at the molecular level, in part because it provides a way to make strong predictions that can be tested against actual data. The neutral theory holds that most variation at the molecular level does not affect fitness and, therefore, the evolutionary fate of genetic variation is best explained by stochastic processes. This theory also presents a framework for ongoing exploration of two areas of research: biased gene conversion, and the impact of effective population size on the effective neutrality of genetic variants.
• Negative Selection
  How are humans contributing to negative selection? It’s a part of evolution that can also drive some species to extinction; models of negative selection help us understand biodiversity.
• Evolutionary Adaptation in the Human Lineage
  Are you lactose intolerant? Many people are. In fact, the ability to digest lactose may be an example of adaptive evolution in the human lineage.
• Natural Selection: Uncovering Mechanisms of Evolutionary Adaptation to Infectious Disease
  The evolutionary link between sickle-cell trait and malaria resistance showed that humans can and do adapt. But are the “bugs” that make us sick evolving as well?
• Negative Selection
  How are humans contributing to negative selection? It’s a part of evolution that can also drive some species to extinction; models of negative selection help us understand biodiversity.
• Genetic Mutation
  Is it possible to have “too many” mutations? What about “too few”? While mutations are necessary for evolution, they can damage existing adaptations as well.

Phylogeny (2)

• Trait Evolution on a Phylogenetic Tree: Relatedness, Similarity, and the Myth of Evolutionary Advancement
  What do phylogenetic trees illustrate? These diagrams don’t just organize knowledge of biodiversity--they also show us that living species are the summation of their evolutionary history.
• Reading a Phylogenetic Tree: The Meaning of Monophyletic Groups
  Phylogenies are a fundamental tool for organizing our knowledge of the biological diversity we observe on our planet. But how exactly do we understand and use these devices?

Speciation (4)

• Hybrid Incompatibility and Speciation
  Often, hybrids between closely related species are often inviable or sterile. How does this sterility and inviability happen? Genetics helps provide insight into answering this question.
• Haldane's Rule: the Heterogametic Sex
  Why are there deformities in male hybrid flour beetles while female hybrids are spared? Haldane’s rule: the male beetles have the heteromorphic sex chromosomes.
• Hybridization and Gene Flow
  What are ways species exchange genes with each other? Hybridization and gene flow are shortcuts to biodiversity that don’t always involve differentiation.
• Why Should We Care about Species?
  The questions "What are species?” and “How do we identify species?” are difficult to answer, and have led to debate and disagreement among biologists. See how consensus on answers to these questions can steer global, political, and financial pressures that affect conservation efforts.