Dr. Alysson Renato Muotri
The Los Angeles Times article Brain’s Darwin Machine said
Alysson Muotri was looking for brain cells that glow in the dark.
With growing frustration, the 31-year-old Brazilian cancer biologist stared through his microscope at slides of brain tissue for any evidence his experiment had succeeded. His eyes ached.
Maria Marchetto, 28, took pity on her husband. Let me look, she said. In a darkened room at the Salk Institute for Biological Studies here, she began to scrutinize the tissue samples for firefly flecks of fluorescent light.
Together, the couple stalked an elusive sequence of DNA hidden in the heredity of every human cell. The wayward strand appeared to seek out developing brain cells and, like a virus, arbitrarily alter their genetic makeup.
In this way, it might be partly responsible for the infinite variety of the mind.
Alysson Renato Muotri, Ph.D. is Fellow at the
Fred H. Gage Laboratory of Genetics,
Salk Institute for Biological Studies. His main research interest is
understanding the formation of brain complexity.
The complexity of the human brain permits the development of
sophisticated behavioral repertoires, such as language, tool use,
self-awareness, symbolic thought, cultural learning and consciousness.
From such dynamic complexity emerged extraordinary technological and
artistic masterpieces in a relatively short cultural history. Brain
complexity has a creative purpose in contrast to others large, but
brute, complex systems such as galaxies and their thousands of billions
of stars.
Brain complexity is the result of millions of years of evolution that
equipped neural stem cells in the embryo with the ability to generate
every neuron in the brain — an extraordinary example of cellular
potency. Understanding what produces neuronal diversification during
brain development has been a longstanding challenge for
neuroscientists.
About half of the nerve cells created in a developing brain have died
by the time that brain has formed. It is believed that a process
similar to natural selection decides cell life or death. But natural
selection requires variation to generate these various cellular
properties.
Such variation was thought to be generated by protein-coding genes.
However, the sequencing of the human genome revealed that genes
represent less than 5% of our genome and thus, there is not enough
information to generate thousands of neuronal types in the brain.
Variation must reside elsewhere. Curiously, around 95% of the
biomedical research is currently focused on these 5%, neglecting the
95% of non-coding regions of the genome.
The lack of obvious function of these sequences inspired the concept of
“junk DNA” to illustrate the idea that such sequences were mere
evolutionary remnants from an ancient RNA World. Part of this junk is
composed of mobile elements, thought to be intracellular selfish
parasites. These “jumping elements” can multiply by a copy-and-paste
mechanism, inserting copies in new genomic locations, occasionally
changing the expression pattern of nearby genes or even creating new
isoforms.
The finding that “jumping genes” impact neuronal genomes challenges the
dogma that neurons are genetically homogeneous units1. They move in a
defined window during neuronal differentiation, changing the genetic
information in single neurons. Such strategy contributes to expand the
number of functionally distinct neurons that could be produced from a
given stem cell gene pool. This characteristic of variety and
flexibility may contribute to the uniqueness of an individual brain,
even between genetically identical twins. These mobile elements may be
part of a conserved core process responsible for evoking facilitated
complex non-random phenotypical variation on which selection may act.
Alysson coauthored
Somatic mosaicism in neuronal precursor cells mediated by L1
retrotransposition,
Development of functional human embryonic stem cell-derived neurons
in
mouse brain,
Alternative Splicing Events Identified in Human Embryonic
Stem Cells and Neural Progenitors,
Photorepair Prevents Ultraviolet-induced Apoptosis in Human Cells
Expressing the Marsupial Photolyase Gene,
Ribozymes and the anti-gene therapy: how a catalytic RNA can be used
to
inhibit gene function, and
Restoring DNA repair capacity of cells from three distinct diseases by
XPD gene-recombinant adenovirus.
Alysson earned a BSc in Biological Sciences from the State University
of Campinas (Unicamp) and earned his PhD in Biology Genetics from
the University of Sao Paulo. Watch his presentation
Development of Functional Human Embryonic Stem Cell-Derived Neurons
in
Mouse Brain at California Institute for Telecommunications and
Information Technology’s
“Stem Cell Meeting on the Mesa”.
Read his LinkedIn profile.