Discovering and Assessing the Genetic Diversity of The Olive Ridley Sea Turtle

Methods

Summary

We will be keeping track of statistics such as gender and number of offspring for each nest. Extractions (6 mm) will be made using a disposable biopsy punch. This will be done on a front flipper as well as the carapace. The carapace has been seen to be a highly successful location for DNA extraction and assessment. This is not harmful to the animal, and can also be done in a necropsy. Each extraction is capable of making multiple samples. We will use DNeasy kits to extract the blood and DNA from the samples. Using gel electrophoresis we can then form a DNA fingerprint and compare the allele frequencies in the population. From here we will be able to assess the relatedness of the population and thus the inbreeding coefficient and genetic diversity. The inbreeding coefficient is a calculation for understanding how inbred the individuals of a population is based off their genes. The closer this value is to one the more inbred the population is which gives us the best understanding of possible health issues that may arise. Genetic diversity can aid in keeping track of the alleles present in a population. This can help with future research by comparing the diversity and seeing if the population is becoming more homozygous (which would be another sign of inbreeding). Too much inbreeding leads to inbreeding depression which can cause health issues and eventually the inability to reproduce. This is why it is important to diagnose it in a population before it is too late.

Challenges

We anticipate the collecting of samples from the sea turtles may present challenges. It is difficult to assess the age of a sea turtle from physical appearances so attaining age varied extracts will pose a challenge. Organizing and keeping the extractions stable and usable will be demanding. Another challenge will be the logistics of keeping track of the individual nests along with the mother and offspring. The handling and return of the sea turtles after collecting, must be done in a way that will not effect their natural and future behaviors. We hope with careful planning and help from local volunteers accustomed with working with the turtles that we can conduct our research in an efficient and organized manner.

Pre Analysis Plan

We hypothesize to find a higher inbreeding coefficient in the newest generation compared to previous generations. We plan to analyze our data from gel electrophoresis. This will allow us to compare and contrast allele frequencies and to test our hypothesis of a higher inbreeding coefficient. It will be important to note that we will be sampling sea turtles with a wide age range and this could account for variance in our results (most successful reproducers may be on one side of the spectrum regarding age). We plan to take this into account with analyzing our data.