My name is Shakthi Rajesh and I am a sophomore majoring in computational biology. This summer I will be investigating the genetic mechanisms behind sex based venom variation within the Florida bark scorpion (Centruroides gracilis), a scorpion species found throughout central and southern Florida. The reason I wanted to work on this project is due to A) my love for all things venomous and B) my experience working as a snake rescuer in southern India. I’m very interested in how and why the composition of venom can vary so greatly, even within the same species.
I would like to understand how the difference in venom could be affected by ecological factors, and how this variation in venom composition can affect how these bite and sting cases need to be treated. To investigate this question, I plan on using several techniques to characterize the venom, identify the genes responsible for the different compounds found in the venom, and sequencing the genome of a male and female scorpion to find out what exactly is causing the variation in venom composition within the species.
I have already collected 30 live individuals (15 of each sex) of the species C. gracilis from Islamorada in the Florida Keys. I have also collected venom samples from each of these live scorpions through electrostimulation of the telson (tail) after anesthetization via CO2. I will use these venom samples to generate RP-HPLC (reversed phase high performance liquid chromatography) profiles for each of the individuals. This is a technique used to separate and analyze complex mixtures of compounds based on their hydrophobicity. This will allow me to determine the degree of variation in the venom between male and female scorpions.
My second step in understanding the variation within the venom of the species is to perform a functional comparison on the venoms of the two sexes. To do this, I will perform lethality trails on model prey types to identify the venom dosage at which half of the tested subjects expire. This will allow me to compare the toxicity of the two sexes’ venoms to see if there is a significant difference.
Next I will perform a transcriptomic and proteomic analysis on the venom to identify what genes are being expressed in the venom and what proteins link to those genes. This will be done by combining data gathered by performing RNA-seq on venom gland tissue along with mass spectrometry. RNA-seq provides us with RNA sequences that are currently being expressed within a tissue and mass spectrometry allows us to identify what compounds are found in the venom. The combination of these two techniques allows us to link the transcriptome or the RNA found within cells to the proteome or the proteins that are found in the venom.
My final step will be to sequence the genomes of a male and female scorpion. Doing this will allow me to uncover how sex is determined in the species and determine how sex is linked with gene expression in chromosomal arrangement.
Combining all these different techniques and steps will provide us with a complete picture of how and why the venoms of the different sexes of the Florida bark scorpion vary. All in all I am incredibly excited to pursue this research project over the summer and I hope to update you soon on all of my progress.
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Hello Shakthi! Your protocol is very interesting, I have no experience in genome or RNA sequencing but I have always found it fascinating. I do have a question though, how do you capture these animals? Do you have set up traps? Do you grab them with your hands? I would love to know how you capture so many without getting seriously hurt.
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