James A. Shapiro
(1943-)
James A. Shapiro is an American biologist, an expert in bacterial genetics and a professor in the Department of Biochemistry and Molecular Biology at the University of Chicago.
For Shapiro, changes to the genome (the DNA sequence or "genetic code") go far beyond the
modern synthesis of Neo-Darwinism, which limits changes in the genetic code to random accidents in DNA sequences that are then selected for having better "fitness" or reproductive success.
Far from a read-only memory (ROM) that can only be changed by random accidents, Shapiro sees the genetic code as a read-write memory that is being changed by cell reproduction, multicellular development, and evolutionary change, including epigenetic and "mobile genetic elements" like
Barbara McClintock's
transposons.
Shapiro proposes several processes that he describes as "natural genetic engineering,"
- Cells operate under changing conditions and
continually make genome inscriptions during cell
reproduction, multicellular development and
evolution.
-
Cells effect genome inscriptions by forming
nucleoprotein complexes, epigenetic formatting
and introducing changes in DNA sequence
structure.
-
Cells actively write data and formatting signals into
their genomes by symbiogenesis, horizontal
transfer and natural genetic engineering (NGE).
-
Cell-regulated, stress- and hybridization-induced
NGE mediates combinatorial changes of coding
sequences, regulatory elements, protein domains
and higher-level genome complexes.
-
Mobile genetic elements rapidly disperse through
genomes and provide shared signals for networks
that functionally integrate different genetic loci.
Shapiro summarizes his new approach to biological evolution...
The genome has traditionally been treated as a Read-Only Memory
(ROM) subject to change by copying errors and accidents. In this
review, I propose that we need to change that perspective and
understand the genome as an intricately formatted Read–Write (RW)
data storage system constantly subject to cellular modifications and
inscriptions. Cells operate under changing conditions and are
continually modifying themselves by genome inscriptions. These
inscriptions occur over three distinct time-scales (cell reproduction,
multicellular development and evolutionary change) and involve a
variety of different processes at each time scale (forming
nucleoprotein complexes, epigenetic formatting and changes in DNA
sequence structure). Research dating back to the 1930s has shown
that genetic change is the result of cell-mediated processes, not
simply accidents or damage to the DNA. This cell-active view of
genome change applies to all scales of DNA sequence variation, from
point mutations to large-scale genome rearrangements and whole
genome duplications (WGDs). This conceptual change to active cell
inscriptions controlling RW genome functions has profound
implications for all areas of the life sciences.
How life changes itself: The Read–Write (RW) genome. Physics of Life Reviews, Vol 10, Iss 3, September 2013, pp.287-383
The philosophical-informational question is: are these point mutations, large-scale genome rearrangements, and whole genome duplications being
controlled or
managed "on purpose" by higher-level processes, or are they themselves randomly produced and put to the natural selection test of reproductive success, like everything else in the
cosmic creation process?
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