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Isolation breeds naivety: island living robs Australian varanid lizards of toad-toxin immunity via four-base-pair mutation.

Ujvari, Beata; Mun, Hee-Chang; Conigrave, Arthur D; Bray, Alessandra; Osterkamp, Jens; Halling, Petter LU and Madsen, Thomas (2013) In Evolution; international journal of organic evolution 67(1). p.289-294
Abstract
Since their introduction to the toad-free Australian continent cane toads (Bufo marinus) have caused a dramatic increase in naïve varanid mortality when these large lizards attempt to feed on this toxic amphibian. In contrast Asian-African varanids, which have coevolved with toads, are resistant to toad toxin. Toad toxins, such as Bufalin target the H1-H2 domain of the α(1) subunit of the sodium-potassium-ATPase enzyme. Sequencing of this domain revealed identical nucleotide sequences in four Asian as well as in three African varanids, and identical sequences in all 11 Australian varanids. However, compared to the Asian-African varanids, the Australian varanids showed four-base-pair substitutions, resulting in the alteration in three of... (More)
Since their introduction to the toad-free Australian continent cane toads (Bufo marinus) have caused a dramatic increase in naïve varanid mortality when these large lizards attempt to feed on this toxic amphibian. In contrast Asian-African varanids, which have coevolved with toads, are resistant to toad toxin. Toad toxins, such as Bufalin target the H1-H2 domain of the α(1) subunit of the sodium-potassium-ATPase enzyme. Sequencing of this domain revealed identical nucleotide sequences in four Asian as well as in three African varanids, and identical sequences in all 11 Australian varanids. However, compared to the Asian-African varanids, the Australian varanids showed four-base-pair substitutions, resulting in the alteration in three of the 12 amino acids representing the H1-H2 domain. The phenotypic effect of the substitutions was investigated in human embryonic kidney (HEK) 293 cells stably transfected with the Australian and the Asian-African H1-H2 domains. The transfections resulted in an approximate 3000-fold reduction in resistance to Bufalin in the Australian HEK293 cells compared to the Asian-African HEK293 cells, demonstrating the critical role of this minor mutation in providing Bufalin resistance. Our study hence presents a clear link between genotype and phenotype, a critical step in understanding the evolution of phenotypic diversity. (Less)
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Contribution to journal
publication status
published
subject
in
Evolution; international journal of organic evolution
volume
67
issue
1
pages
289 - 294
publisher
Wiley-Blackwell
external identifiers
  • wos:000313364500023
  • pmid:23289579
  • scopus:84871945658
ISSN
1558-5646
DOI
10.1111/j.1558-5646.2012.01751.x
language
English
LU publication?
yes
id
ba103c42-260a-48c4-a0a9-5f5f98f663cb (old id 3439017)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/23289579?dopt=Abstract
date added to LUP
2013-02-04 10:22:56
date last changed
2017-09-24 04:41:04
@article{ba103c42-260a-48c4-a0a9-5f5f98f663cb,
  abstract     = {Since their introduction to the toad-free Australian continent cane toads (Bufo marinus) have caused a dramatic increase in naïve varanid mortality when these large lizards attempt to feed on this toxic amphibian. In contrast Asian-African varanids, which have coevolved with toads, are resistant to toad toxin. Toad toxins, such as Bufalin target the H1-H2 domain of the α(1) subunit of the sodium-potassium-ATPase enzyme. Sequencing of this domain revealed identical nucleotide sequences in four Asian as well as in three African varanids, and identical sequences in all 11 Australian varanids. However, compared to the Asian-African varanids, the Australian varanids showed four-base-pair substitutions, resulting in the alteration in three of the 12 amino acids representing the H1-H2 domain. The phenotypic effect of the substitutions was investigated in human embryonic kidney (HEK) 293 cells stably transfected with the Australian and the Asian-African H1-H2 domains. The transfections resulted in an approximate 3000-fold reduction in resistance to Bufalin in the Australian HEK293 cells compared to the Asian-African HEK293 cells, demonstrating the critical role of this minor mutation in providing Bufalin resistance. Our study hence presents a clear link between genotype and phenotype, a critical step in understanding the evolution of phenotypic diversity.},
  author       = {Ujvari, Beata and Mun, Hee-Chang and Conigrave, Arthur D and Bray, Alessandra and Osterkamp, Jens and Halling, Petter and Madsen, Thomas},
  issn         = {1558-5646},
  language     = {eng},
  number       = {1},
  pages        = {289--294},
  publisher    = {Wiley-Blackwell},
  series       = {Evolution; international journal of organic evolution},
  title        = {Isolation breeds naivety: island living robs Australian varanid lizards of toad-toxin immunity via four-base-pair mutation.},
  url          = {http://dx.doi.org/10.1111/j.1558-5646.2012.01751.x},
  volume       = {67},
  year         = {2013},
}