Explanation:
Introduction
Our modern understanding of DNA role in heredity has led to a variety of practical applications, including forensic analysis, paternity testing, and genetic screening. Thanks to these wide-ranging uses, today many people have at least a basic awareness of DNA.
It may be surprising, then, to realize that less than a century ago, even the best-educated members of the scientific community did not know that DNA was the hereditary material!
In this article, we'll look at some of the classic experiments that led to the identification of DNA as the carrier of genetic information.
Protein vs. DNA
The work of Gregor Mendel showed that traits (such as flower colors in pea plants) were not inherited directly, but rather, were specified by genes passed on from parents to offspring. The work of additional scientists around the turn of the 20th century, including Theodor Bovari, Walter Sutton, and Thomas Hunt Morgan, established that Mendel's heritable factors were most likely carried on chromosomes.
Scientists first thought that proteins, which are found in chromosomes along with DNA, would turn out to be the sought-after genetic material. Proteins were known to have diverse amino acid sequences, while DNA was thought to be a boring, repetitive polymer, due in part to an incorrect (but popular) model of its structure and composition1
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Today, we know that DNA is not actually repetitive and can carry large amounts of information, as discussed further in the article on discovery of DNA structure. But how did scientists first come to realize that "boring" DNA might actually be the genetic material?
