Memory is one of the highest cognitive functions that differentiates higher
organisms from others because of its fundamental function to all learning and
studying process. Recently, it was suggested that lactate works as a signaling
molecule in neuronal plasticity system in long-term memory (LTM). These
functions are reported only at mice so far, but it would be a universal
phenomenon among various higher organisms. Because lactate is organic acid
that is involved with energy production, it is of particular interest to know how
memory associated genes including lactate-mediated neural plasticity (LMNP)
genes get involved during evolution. I here set the purpose of my studies to
understand the evolutionary origin and process of these memory-associated
genes. Conducting an extensive literature survey, I collected a total of 302 genes
of mice as memory associated genes. I, then, compared the number of genes
orthologous to the 302 mice memory-associated genes among 11 representative
organisms that I have chosen for the present study. As a result, I found that these
memory-associated genes emerged at different time points during evolution,
even before the emergence time of the organisms where memory function was
reported. It suggests that memory function could be evolutionarily established
gradually but not at once. Moreover, I examined 386 of LMNP-related genes of
mice and other organisms to understand the evolutionary origin and processes
of those genes that were identified by RNA-seq analyses (Margineanu et al.,
2018). I found that the emergence times of LMNP genes were varied with genes,
suggesting that the LMNP system may have been also formed gradually until its
completion of the system around at the time of the common ancestor of
vertebrates. Interestingly, I found that there are 13 genes overlap between the
memory system and the LMNP system, indicating the critical role of those genes
in connecting between both systems. From those studies, I conclude that the
memory system and LMNP system has been formed by gradual participation of
newly emerging genes during evolution, suggesting that the function of LMNP as
a signaling molecule may be evolutionarily related to memory system by an
unknown system that may exist to link both systems.
Date of Award | Sep 2019 |
---|
Original language | English (US) |
---|
Awarding Institution | - Biological, Environmental Sciences and Engineering
|
---|
Supervisor | Takashi Gojobori (Supervisor) |
---|
- Evolution
- Memory
- Lactate Mediated Neural Plasticity
- Astrocyte Neuron Lactate Shuttle