structure of proteins required the strenuous effort of a host of
brilliant biochemists, chemists, and physicists. In the past century,
many of them have been awarded by Nobel prize. The first big
achievement was made by Max Perutz who described the structure
of hemoglobin tetramer [4], which gained him and his fellow John
Kendrew (for the structure of the cognate protein myoglobin) the
1962 Nobel Prize in Chemistry.
In the same years, a second star molecule, DeoxyriboNucleic
Acid (DNA), was gaining moment. First described by Miescher [5]
in 1869 and analyzed by Levene [6] in 1919, DNA took the centre
stage in 1953, thanks to a most famous paper by Watson and Crick
[7], perhaps one of the clearest and more provoking scientific
articles that everyone studying biology must read.
In this paper, James and Francis put down the basis of genetic
code which since then has been the favorite issue of thousands of
scientists all over the world, of many pharmaceutical and diagnostic
firms, and even of lay people whose a frequent locution became: “It
is in my (his, their, its) DNA”.
This “fashion” reached its climax around the turning of millennium when the whole human genome was decrypted [8] and the
individual DNA sequence made available by skilled entrepreneurs
for a handful of dollars. It came out that only a tiny fraction (2%)
of the DNA filament was actually coding for proteins, inducing
several scientists to preposterously call the remaining part “junk
DNA” [9]. However, after a few years, the finding of new functions
for the noncoding regions of the DNA molecule induced the
scientific community to reconsider the matter [10].
In the meantime, it started a more accurate search for the role
of RiboNucleic Acid (RNA), which till then considered no more
than an efficient and compliant servant with three different attitudes (messenger, mRNA; transfer, tRNA; and ribosomal, rRNA).
This simplistic view was soon abandoned by the discovery of several
new types and functions of RNA. Just to mention a few, we today
acknowledge the presence and function of heterogeneous nuclear
(hnRNA), small interfering (siRNA), short hairpin (shRNA), piwiinteracting (piRNA), micro (miRNA), and small nucleolar
(snoRNA) ribonucleic acids, not to mention double strand RNA
(dsRNA) found in some viruses.
The most recent finding about RNA is its ability to serve as a
catalyst in several reactions involving DNA, proteins, and RNA
itself [11, 12]. This particular ability gave room to hypothesize a
“RNA world” when ribonucleic acid might have been the unopposed king of all the living matter, before the appearance of proteins
on earth and then the takeover by DNA as repository of genetic
information [13, 14].
Nonetheless, it was evident that proteins, with their much
greater possibility of variation, these being written with 20 different
2
Alessandro Finazzi Agro ` and Giampiero Mei
brilliant biochemists, chemists, and physicists. In the past century,
many of them have been awarded by Nobel prize. The first big
achievement was made by Max Perutz who described the structure
of hemoglobin tetramer [4], which gained him and his fellow John
Kendrew (for the structure of the cognate protein myoglobin) the
1962 Nobel Prize in Chemistry.
In the same years, a second star molecule, DeoxyriboNucleic
Acid (DNA), was gaining moment. First described by Miescher [5]
in 1869 and analyzed by Levene [6] in 1919, DNA took the centre
stage in 1953, thanks to a most famous paper by Watson and Crick
[7], perhaps one of the clearest and more provoking scientific
articles that everyone studying biology must read.
In this paper, James and Francis put down the basis of genetic
code which since then has been the favorite issue of thousands of
scientists all over the world, of many pharmaceutical and diagnostic
firms, and even of lay people whose a frequent locution became: “It
is in my (his, their, its) DNA”.
This “fashion” reached its climax around the turning of millennium when the whole human genome was decrypted [8] and the
individual DNA sequence made available by skilled entrepreneurs
for a handful of dollars. It came out that only a tiny fraction (2%)
of the DNA filament was actually coding for proteins, inducing
several scientists to preposterously call the remaining part “junk
DNA” [9]. However, after a few years, the finding of new functions
for the noncoding regions of the DNA molecule induced the
scientific community to reconsider the matter [10].
In the meantime, it started a more accurate search for the role
of RiboNucleic Acid (RNA), which till then considered no more
than an efficient and compliant servant with three different attitudes (messenger, mRNA; transfer, tRNA; and ribosomal, rRNA).
This simplistic view was soon abandoned by the discovery of several
new types and functions of RNA. Just to mention a few, we today
acknowledge the presence and function of heterogeneous nuclear
(hnRNA), small interfering (siRNA), short hairpin (shRNA), piwiinteracting (piRNA), micro (miRNA), and small nucleolar
(snoRNA) ribonucleic acids, not to mention double strand RNA
(dsRNA) found in some viruses.
The most recent finding about RNA is its ability to serve as a
catalyst in several reactions involving DNA, proteins, and RNA
itself [11, 12]. This particular ability gave room to hypothesize a
“RNA world” when ribonucleic acid might have been the unopposed king of all the living matter, before the appearance of proteins
on earth and then the takeover by DNA as repository of genetic
information [13, 14].
Nonetheless, it was evident that proteins, with their much
greater possibility of variation, these being written with 20 different
2
Alessandro Finazzi Agro ` and Giampiero Mei