Question

who first identified dna?
rosalind franklin
erwin chargaff
friedrich miescher
james watson

Explanation:

• Rosalind Franklin: Known for her work on the X - ray diffraction images of DNA (like Photo 51), which was crucial for understanding DNA's structure, but not the first to identify DNA.
• Erwin Chargaff: Discovered Chargaff's rules (A = T, G = C in DNA), but not the first to identify DNA.
• Friedrich Miescher: In 1869, he isolated a substance from the nuclei of white blood cells (leukocytes) in pus - stained bandages. He called this substance "nuclein" (which we now know as DNA). So he was the first to identify DNA.
• James Watson: Along with Francis Crick, proposed the double - helix structure of DNA in 1953, but not the first to identify DNA.

Answer:

Friedrich Miescher