What observations are consistent with the conclusion that DNA serves as the genetic material in eukaryotes? List and discuss them.

The first indirect evidence for DNA as the genetic material came from Frederick Griffith's experiment in 1928. Griffith observed that when a harmless strain of pneumonia bacteria (Streptococcus pneumoniae) was mixed with heat-killed virulent bacteria, the harmless strain became virulent. This phenomenon, called transformation, suggested that some "transforming principle" from the dead virulent bacteria was taken up by the harmless bacteria, which then inherited the ability to cause disease. Although Griffith did not identify DNA as the transforming principle, his work laid the foundation for future research in this field.

Building upon Griffith's work, in 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that the transforming principle observed by Griffith was, in fact, DNA. They performed a series of experiments using various enzymes to break down proteins, lipids, and nucleic acids in the heat-killed virulent bacteria. Only when they broke down the DNA, the harmless bacteria stopped transforming into the virulent strain. This provided strong evidence that DNA is the genetic material responsible for the transformation phenomenon.

The next conclusive piece of evidence came from the work of Alfred Hershey and Martha Chase in 1952. They used viruses (bacteriophages) that infect bacteria to study the role of DNA in transferring hereditary information. Hershey and Chase labeled the viral DNA with radioactive phosphorus (P32) and the protein coat with radioactive sulfur (S35). They observed that after the infection process, only the radioactive phosphorus was detected inside the bacteria, while the radioactive sulfur remained outside. This experiment demonstrated that the viral DNA, not the protein, entered the host cell and directed the production of new viruses, providing strong support for DNA as the genetic material.

In 1953, James Watson and Francis Crick proposed the double helix structure of DNA, based on X-ray diffraction data obtained by Rosalind Franklin and Maurice Wilkins. The double helix structure explains how DNA can be replicated and how genetic information can be encoded in the sequence of nucleotide bases (adenine, thymine, guanine, and cytosine). The base pairing rules (adenine pairs with thymine and guanine pairs with cytosine) allow DNA to serve as a stable and efficient carrier of genetic information.

The central dogma of molecular biology, formulated by Francis Crick in 1958, describes the flow of genetic information from DNA to RNA to protein in living organisms. DNA serves as the template for the synthesis of RNA (transcription), which in turn serves as the template for the synthesis of proteins (translation). This process ultimately determines the structure and function of cells, thus providing an additional piece of evidence that DNA is the genetic material responsible for heredity and cellular traits in eukaryotes. In conclusion, various experiments and observations have demonstrated the role of DNA as the genetic material in eukaryotes, with each piece of evidence building upon and reinforcing the findings of earlier research.