2024 Virtual GREAT Day Program
Search
Poster
Cooperation of Selfish Genetic Elements in Stalk-Eyed Flies
Suhani Patel , Benjamin McPherson
FACULTY SPONSOR:
Josephine Reinhardt, Biology
SGEs are selfish genetic elements that increase the likelihood of their own transmission regardless of the host’s best interest. Transposable elements (TEs) and meiotic drivers are both types of SGEs. SGEs subsequently result in genetic conflict as they disrupt functional elements in the genome. We are working to better understand the cooperation of selfish genetic elements in Stalk-Eyed flies. Transposable elements are counteracted by small non-coding RNA molecules called piRNA. These RNA molecules work by reducing the expression of TEs by degrading TE RNA transcripts. Prior work in stalk-eyed flies has shown that TEs are expressed at a higher rate in male carriers of meiotic drive (SR males). We are comparing the expression of piRNA in SR and wild-type males using small RNA sequencing analysis software (proTRAC, PILFER) designed for this type of data. If meiotic drive and TEs cooperate, we would expect to see increased expression of piRNAs targeting TEs in SR males.
Single Presentation/Performance
Simulating Sex-Ratio Meiotic Drive in Teleopsis dalmanni using SLiM
Julia May , Ji Min Son , Usman Chaudhry
FACULTY SPONSOR:
Josephine Reinhardt, Biology
The law of segregation states that alleles are inherited fifty percent of the time. Meiotic drive breaks this law by changing the inheritance rate to one hundred percent. Sex-ratio meiotic drive is where the sex ratio decreases because the X chromosome is always passed along, leading to more females than males being produced. This may introduce issues like extinction and selective mating patterns between drive and non-drive flies. Could meiotic drive affect the fitness of a population if the population does not go extinct? In order to address this question, we will use SLiM, a flexible population genetics simulator. We have been able to achieve a model that allows for drive to persist in a population with neutral mutations. Multiple graphs have also been generated using fitness values of each drive phenotype to see how often the drive was maintained. This allowed us to observe how the fitness of each phenotype played a role in maintaining drive in the population. For a more realistic model, we will be adding beneficial and deleterious mutations to see how drive affects fitness at the individual level. Our long term goals are to add inversions and sexual selection to our model.
Effects of Meiotic Drive on Developing Eye-Stalks in Stalk-Eyed Flies
Olivia Smith , Karissa Garbarini , Heather Wood
FACULTY SPONSOR:
Josephine Reinhardt, Biology
Teleopsis dalmanni, known as Stalk-Eyed flies, are known for their sexually dimorphic eye-stalks. In the wild, some contain meiotic drive which minimizes eye-stalk length and disrupt the sex ratios. Our goal is to identify genes in developing eye tissue that are affected by meiotic drive. Since eye stalks are a sexual ornamentation females prefer to mate with males with larger eye stalks, therefore males with shorter eyestalks have a lower fitness. To identify these candidate genes, we dissected eye antennal discs from larvae and retained the carcasses. We extracted DNA from the carcasses, and performed PCR for markers diagnosing the sex and meiotic drive status, then did fragment analysis. We identified 31 males and 1/3rd of the population had meiotic drive. We are using the larvae’ eye-antennal imaginal discs from our dissections to measure differential gene expression using RNA from meiotic and non-meiotic drive individuals of each sex. After pooling tissues together by drive we were able to do RNA extractions using RNeasy extraction kit and sent these samples for RNA sequencing. Kallisto will quantify the RNA-seq data, allowing us to compare the extracted RNA samples to the entire genome to see what genes are being expressed.