The first scientist to isolate DNA was Frederick Miescher.

Step 1: Understanding the Question

The question asks for the first scientist to isolate DNA. This is a historical fact in the field of biology.

Step 2: Reviewing the Options

• Frederick Miescher: A Swiss physician and biologist.
• Charles Darwin: An English naturalist famous for his theory of evolution by natural selection.
• Mendel (Gregor Mendel): An Austrian scientist, known as the father of genetics for his work with pea plants.
• Watson and Crick: James Watson and Francis Crick, who are credited with discovering the double-helix structure of DNA in 1953.

Step 3: Recalling the Historical Event

In 1869, Friedrich (Frederick) Miescher was working in the laboratory of Felix Hoppe-Seyler. While studying the composition of white blood cells, he isolated a substance from the cell nuclei that was not a protein and had unique chemical properties. He named this substance "nuclein," which we now know as deoxyribonucleic acid (DNA). This was the first time DNA had been isolated and identified as a distinct molecule.

Step 4: Eliminating Other Options

• Charles Darwin's work on evolution was published in 1859, before DNA was even known to exist.
• Gregor Mendel's groundbreaking work on inheritance was published in 1866, but he worked with traits in pea plants, not the physical/chemical substance responsible for them.
• Watson and Crick's work on the structure of DNA occurred much later, in 1953, long after the molecule had been discovered and isolated.

Final Answer

Therefore, the correct answer is Frederick Miescher.

Related Topics & Formulae

While this is a historical fact and does not involve mathematical formulae, it is a foundational concept in molecular biology.

Key Theory: The Discovery of DNA

The journey to understand DNA involved several key scientists:

• 1869: Isolation - Friedrich Miescher isolates "nuclein."
• Early 1900s: Role Hypothesized - Scientists like Phoebus Levene identified its basic components (sugar, phosphate, base) and suggested it was a polymer.
• 1928: Transformation Principle - Frederick Griffith's experiments with bacteria showed that some "transforming principle" could change the characteristics of a cell.
• 1944: DNA as Genetic Material - The Avery–MacLeod–McCarty experiment identified DNA as Griffith's "transforming principle," proving it carries genetic information.
• 1952: Confirmation - The Hershey–Chase experiment provided further proof that DNA is the genetic material.
• 1953: Structure Solved - Using X-ray crystallography data from Rosalind Franklin and Raymond Gosling, James Watson and Francis Crick proposed the double-helix model of DNA.

This timeline shows that Miescher's work was the crucial first step that made all future discoveries possible.