Does Darwin's Comparison of DNA Sequences Provide Strong Evidence of Evolution?

Charles Darwin, known for his groundbreaking theories on evolution, never directly compared DNA sequences. He lived and worked in a time when DNA was not yet discovered, and the techniques to sequence it did not exist until the 20th century. Nonetheless, the comparison and analysis of DNA sequences today provide compelling evidence of evolution, consistent with neoDarwinian theory.

Understanding DNA and Evolution

It is important to note that Darwin had no knowledge of DNA. His understanding of inheritance and evolution was based on observable traits, comparative physiology, and the fossil record. The discovery of DNA and the development of techniques to sequence it occurred decades after Darwin’s death. In 1953, James Watson and Francis Crick elucidated the double helix structure of DNA, thereby laying the foundation for molecular biology and genetics.

Evidence from DNA Sequencing

Modern scientific techniques, which include DNA sequencing, have provided robust evidence supporting the theory of evolution. When we compare DNA sequences among different species, we see clear patterns that align with the principles of neoDarwinian evolution. This form of evidence is compelling because it provides direct, tangible proof of the genetic similarities and differences between species.

Geneticists use various statistical methods to infer evolutionary relationships based on DNA sequences. These methods are consistent with the principles outlined by Darwin, but with more detailed and precise data. For instance, phylogenetic analysis allows scientists to construct evolutionary trees that illustrate the relationships between different species. These trees are based on genetic similarities and differences, providing a visual representation of how species have evolved over time.

NeoDarwinian Evolution and DNA Sequences

The term ‘neoDarwinian evolution’ refers to the modern synthesis that integrates Darwin's theory of natural selection with the principles of genetics and molecular biology. The statistics derived from DNA sequences are consistent with the population genetics theory that underpins neoDarwinian evolution. This means that the evidence from DNA sequencing is not just indirect or suggestive, but is actually direct evidence for neoDarwinian evolution.

For example, through comparative genomics, scientists have observed that closely related species share more DNA sequences than distantly related species. This is a clear sign of shared ancestry. Additionally, mutations in DNA sequences serve as the raw material for evolutionary change, as described by Darwin. The function of these mutations can be studied, and their effects on the fitness of organisms can be measured, providing a comprehensive picture of evolutionary processes.

Conclusion: Evidence for Evolution

To summarize, while Darwin did not directly compare DNA sequences, the evidence from modern DNA sequencing provides strong support for the theory of evolution. Contemporary scientists continue to refine our understanding of the mechanisms of evolution, but the basic principles—and the evidence supporting them—remain consistent with and indeed furthered by Darwin's original ideas.

So when we say that measured DNA sequences are evidence for neoDarwinian evolution, we are not merely making an abstract claim. The evidence is concrete and measurable, providing a solid foundation for the modern understanding of evolution.