Divergence of Vertebrate and Insect Specific Toxin Genes between Two Species of Widow Spider Latrodectus geometricus and Latrodectus tredecimguttatus
Primary Faculty Mentor’s Name
Dr John Scott Harrison
Proposal Track
Student
Session Format
Poster
Abstract
The brown widow spider, Latrodectus geometricus, is an introduced species to the southern United States (Brown 2008). The brown widow is a member of the widow spider genus Latrodectus which includes the southern black widow (L. mactans) and seventeen other venomous species. All species of widow spiders produce venom which is used against both predator and prey. These venoms are composed of several different species specific toxins, each encoded by a different gene (Graudins 2012). Previous research has shown that positive selection pressures affect the venom of snakes and snails, thus aiding in adaptive potential of the species (Gibbs 2007; Duda 1999). The study presented here was designed to analyze the nucleotide and amino acid differences between Brown and Black widow spiders at two toxin genes. The purpose of the investigation was two-fold: 1) to characterize the nucleotide and amino acid divergence in latroinsectotoxin between the Brown widow and Mediterranean Black widow spiders, and 2) compare levels of divergence to that of α-latrotoxin and a non-toxin gene Cytochrome Oxidase I. It was found that nucleotide difference did lead to large amino acid differences between species for the two toxin genes. Amino acid variation was found to be high suggesting potential differences in functionality and toxicity. Greater amino acid variance at the back portion of the gene suggests that the front portion is more conserved and potentially more critical for function. The large between species in the toxin genes as compared to the non-toxin gene (COI) suggests positive selection pressures acting on the toxin genes.
Keywords
Latrodectus geometricus, Widow spiders, Latroinsectotoxin, α-latrotoxin, Nucleotide divergence, Amino acid difference, Toxin genes
Location
Concourse/Atrium
Presentation Year
2014
Start Date
11-15-2014 2:55 PM
End Date
11-15-2014 4:10 PM
Publication Type and Release Option
Presentation (Open Access)
Recommended Citation
Kahn, Shannon G., "Divergence of Vertebrate and Insect Specific Toxin Genes between Two Species of Widow Spider Latrodectus geometricus and Latrodectus tredecimguttatus" (2014). Georgia Undergraduate Research Conference (2014-2015). 103.
https://digitalcommons.georgiasouthern.edu/gurc/2014/2014/103
Divergence of Vertebrate and Insect Specific Toxin Genes between Two Species of Widow Spider Latrodectus geometricus and Latrodectus tredecimguttatus
Concourse/Atrium
The brown widow spider, Latrodectus geometricus, is an introduced species to the southern United States (Brown 2008). The brown widow is a member of the widow spider genus Latrodectus which includes the southern black widow (L. mactans) and seventeen other venomous species. All species of widow spiders produce venom which is used against both predator and prey. These venoms are composed of several different species specific toxins, each encoded by a different gene (Graudins 2012). Previous research has shown that positive selection pressures affect the venom of snakes and snails, thus aiding in adaptive potential of the species (Gibbs 2007; Duda 1999). The study presented here was designed to analyze the nucleotide and amino acid differences between Brown and Black widow spiders at two toxin genes. The purpose of the investigation was two-fold: 1) to characterize the nucleotide and amino acid divergence in latroinsectotoxin between the Brown widow and Mediterranean Black widow spiders, and 2) compare levels of divergence to that of α-latrotoxin and a non-toxin gene Cytochrome Oxidase I. It was found that nucleotide difference did lead to large amino acid differences between species for the two toxin genes. Amino acid variation was found to be high suggesting potential differences in functionality and toxicity. Greater amino acid variance at the back portion of the gene suggests that the front portion is more conserved and potentially more critical for function. The large between species in the toxin genes as compared to the non-toxin gene (COI) suggests positive selection pressures acting on the toxin genes.
