Last week of processing, hopefully all the sequences come back good and we’ll be moving on to computer work. A good amount of my last set of sequences came back fuzzy and unreadable, which is a bummer. I guess it happens since we are using universal primers, any DNA in the tissue sample will also be read (even the DNA of the worms last meal). I used the center portion of a few of the worms so that I could preserve the posterior end for morphology but that may have been a mistake since that area also contains the gut region but its hard to know for sure if that was the issue. Thankfully it turns out that there are other options to try that may still work. Either way, it has provided another learning opportunity of how to problem solve issues that might arise and has helped me to better understand the whole process. Using certain primers that are designed to target a different fragment of DNA specific to nemertean worms may help. These primers will still isolate the same CO1 gene sequence. Keeping the same gene sequence is important for comparison in species identification. Using primers that are more specific to Nemertean DNA will help exclude any non-nemertean DNA from the sample. We will be running the new primers on Friday so we will find out next week if it worked. The last of the worms were photographed this week and I tried my hand at dissecting and removing the stylets for photographs. All Nemertean worms have a proboscis which is sort of like a harpoon that they shoot out to poison and capture their prey. In some species their toxins are excreted out the length of the proboscis which they can then wrap around their prey to immobilize them. Other species have a dagger like appendage at the end of their proboscis called a stylet that allows them to puncture their prey and inject their poison. These worms also have what we refer to as accessory pouches which is where new stylets are made and stored. Different species will have different style stylets and pouches so it is important to document and photograph this section as part of that worms individual features. The worms are so small the dissection and removal of the stylet has to be done under a microscope. It was definitely a bit challenging but also rewarding once it was successfully removed and placed onto a microscope slide for photographs.
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Rebecca OrrHi, my name is Rebecca I’m from Northern California. My major is in biological sciences. I am so excited to be working in Dr. Svetlana Maslakova’s lab and learning the protocol and procedures for completing a modern biodiversity survey. Archives
August 2021
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