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Genom untuk sequencing King Cobra
Genome for the king cobra sequenced
Date:
December 3,
2013
Source:
Liverpool School of Tropical
Medicine
Summary:
Biologists who have recently sequenced the genome of
the king cobra, say that their work reveals dynamic evolution and adaptation in
the snake venom system, which seemingly occurs in response to an evolutionary
arms race between venomous snakes and their prey.
.............................
Researchers from LSTM, along with a team of international
biologists who have recently sequenced the genome of the king cobra, say that
their work reveals dynamic evolution and adaptation in the snake venom system,
which seemingly occurs in response to an evolutionary arms race between
venomous snakes and their prey.
A paper
co-lead by Dr Nicholas Casewell, a NERC research Fellow at LSTM, and 34
co-authors from six countries, including the Director of the Alistair Reid
Venom Unit at LSTM, Dr Robert Harrison, has been published in the Proceedings
of the National Academy of Sciences (PNAS). Members of this team also
analysed the genome of the Burmese python (Python molurus bivittatus)
and used it for comparison with the king cobra (Ophiophagus Hannah).
These papers represent the first complete and annotated snake genomes.
Snake venoms
are complex protein mixtures encoded by several gene families and these
proteins function synergistically to cause rapid paralysis or death in prey.
The study provides an insight into the biology of the venom in snakes, and
allows the understanding of the evolution of venom genes at the genome
structural level. Armed with the both the king cobra and Burmese python genome
the team was able to show that, despite previous hypotheses that venom genes
evolve "early" in the lineage leading to snakes, venom gene families
do not duplicate early, in fact the study shows that the rapid and extensive
expansion of functionally important venom toxin families is restricted to the
venomous "advanced" snake lineage.
The
diversification of these toxins correlates directly with their functional importance
in prey capture, for example the most pathogenic king cobra toxin family have
undergone massive expansion, while, in contrast, venom proteins with less
important functions do not participate in the evolutionary arms race occurring
between snakes and their prey.
Dr Nicholas
Casewell said: "These are the first snake genomes to be sequenced and
fully annotated and our results in relation to the king cobra provide a unique
view of the origin and evolution of snake venom, including revealing multiple
genome-level adaptive responses to natural selection in this complex biological
weapon system. These adaptations include the massive and rapid expansion of
gene families that produce venom toxins, providing the snake with a highly
toxic protein mixture required to overcome a variety of different prey and also
circumvent any resistance to venom that may have developed in such prey. Our
study provides unique genome-wide perspectives on the adaptive evolution of
venom systems as well as protein evolution in general. As such it contributes
an essential foundation for understanding and comparing evolutionary genomic
processes in venomous organisms."
The work
carried out by Dr Casewell and his co-authors was used in the second paper
outlining the analysis of the genome of the Burmese python, also published in
the same edition of PNAS.
Story
Source:
The above
story is based on materials provided by Liverpool School of Tropical Medicine. Note: Materials may be edited
for content and length.
Journal
References:
- F. J. Vonk, N. R. Casewell, C. V. Henkel, A. M. Heimberg, H. J. Jansen, R. J. R. McCleary, H. M. E. Kerkkamp, R. A. Vos, I. Guerreiro, J. J. Calvete, W. Wuster, A. E. Woods, J. M. Logan, R. A. Harrison, T. A. Castoe, A. P. J. de Koning, D. D. Pollock, M. Yandell, D. Calderon, C. Renjifo, R. B. Currier, D. Salgado, D. Pla, L. Sanz, A. S. Hyder, J. M. C. Ribeiro, J. W. Arntzen, G. E. E. J. M. van den Thillart, M. Boetzer, W. Pirovano, R. P. Dirks, H. P. Spaink, D. Duboule, E. McGlinn, R. M. Kini, M. K. Richardson. The king cobra genome reveals dynamic gene evolution and adaptation in the snake venom system. Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1314702110
- T. A. Castoe, A. P. J. de Koning, K. T. Hall, D. C. Card, D. R. Schield, M. K. Fujita, R. P. Ruggiero, J. F. Degner, J. M. Daza, W. Gu, J. Reyes-Velasco, K. J. Shaney, J. M. Castoe, S. E. Fox, A. W. Poole, D. Polanco, J. Dobry, M. W. Vandewege, Q. Li, R. K. Schott, A. Kapusta, P. Minx, C. Feschotte, P. Uetz, D. A. Ray, F. G. Hoffmann, R. Bogden, E. N. Smith, B. S. W. Chang, F. J. Vonk, N. R. Casewell, C. V. Henkel, M. K. Richardson, S. P. Mackessy, A. M. Bronikowsi, M. Yandell, W. C. Warren, S. M. Secor, D. D. Pollock. The Burmese python genome reveals the molecular basis for extreme adaptation in snakes. Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1314475110