The plastic cobras: omics investigation of venom evolveability and allopatric variation
Snake venom is a complex polygenic trait driven by selection and is reflective of local adaptation of snakes to different ecological niches. The advent in –omics technologies has greatly improved the profiling of snake venom compositions, thereby providing a solid platform for investigating the m...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Conference or Workshop Item |
| Language: | en |
| Published: |
2016
|
| Subjects: | |
| Online Access: | http://eprints.um.edu.my/16488/1/Abstract_ID163_in_8WCH_2016_handbook.pdf http://eprints.um.edu.my/16488/ |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Snake venom is a complex polygenic trait driven by selection and is reflective of local
adaptation of snakes to different ecological niches. The advent in –omics technologies
has greatly improved the profiling of snake venom compositions, thereby providing a
solid platform for investigating the mechanistic details underlying the evolutionary
process of venom variability. Applying a venomic approach that integrates
reversed-phase HPLC, gel-electrophoresis and nano-ESI-LCMS/MS, we profiled and
compared the venoms of three Asiatic cobra species sourced from different
geographical localities of their native distribution (Naja naja: Pakistan, India, Sri
Lanka; Naja kaouthia: Thailand, Malaysia, Vietnam; Naja sumatrana: Thailand,
northern and southern Malaysia, Sumatran Indonesia). Variations in venom
composition are evident at intra-generic and intra-specific levels for all three cobra
species, particularly on the expression of key toxins, i.e. alpha-neurotoxins and
cytotoxins that are essential for predation and digestion. Of note, the Pakistani N. naja,
Thai N. kaouthia and Indonesian N. sumatrana possess the highest content of
neurotoxins (20-50% total venom proteins, in varied long-chain or short-chain
isoforms), and these correlate with their potent lethal effects (LD50 = 0.2-0.4 μg/g in
mice) and the syndromic evolution, as well as antigenic responses to region-specific
antivenom. Furthermore, Illumina HiSeq technology applied for comparative
venom-gland transcriptomics of N. kaouthia has allowed the mapping of specific
transcripts to toxins of significance, thereby correlating the toxin genotype to
phenotypic venom variation. Our findings revealed that although most toxin genes are
highly conserved, distinct differential gene expression was remarkable, indicating
up-regulation of gene transcription for selected toxins, or enhanced mRNA
degradation or lack of transcription due to pseudogenization of certain traits. The
findings highlight the significance of the plasticity of key-toxin compositions in
cobras as unique venom phenotypes, and provide critical insights intoenvenomation
pathophysiology as well as the formulation of an effective pan-regional antivenom. |
|---|