SGER: Effects of Interpopulation Hybridization on DNA Methylation

这个项目调查了DNA甲基化的变化在物种形成的早期阶段发挥作用的可能性。在对加州虎脚亚种的扩增片段长度多态(AFLP)进行筛选的过程中，发现DNA的特定区域在一个种群中发生了甲基化，而在另一个种群中没有。此外，不同种群之间的杂交似乎会引起甲基化的变化。这一SGER试图通过使用甲基化敏感的AFLP在比过去使用的更广泛的杂交中筛选大量基因座来更明确地测试亲本和杂交种之间的甲基化差异。由于甲基化DNA在整个基因组中的分布在无脊椎动物中知之甚少，在这种特殊物种中完全未知，因此将使用一种特定于基因座的技术来分析选定的微卫星、核糖体DNA和蛋白质编码基因座上的甲基化。这项工作具有医学意义，因为DNA甲基化在从转录调控到自发突变再到癌症发生的一系列过程中发挥着作用。如果杂交引起的甲基化变化得到证实，这对旨在促进种群间混合的保护和管理实践具有相当大的影响。本科生和研究生都将参与这个项目，并学习分子和进化遗传学的各种技术。

This project investigates the possibility that changes in DNA methylation play a role in the early stages of speciation. In the process of screening amplified fragment length polymorphisms (AFLPs) in the copepod Tigriopus californicus, particular regions of DNA were found to be methylated in one population but not in another. Further, hybridization between populations appeared to induce changes in methylation. This SGER seeks to more definitively test for methylation differences between parentals and hybrids by using methylation-sensitive AFLP to screen a large number of loci in a much wider cross than was used in the past. Because the distribution of methylated DNA throughout the genome is poorly known in invertebrates and wholly unknown in this particular species, a locus-specific technique will be used to assay methylation at selected microsatellite, ribosomal DNA and protein-coding loci. Such work has medical implications due to the role of DNA methylation in processes ranging from transcription regulation to spontaneous mutation to carcinogenesis. If hybridization-induced changes in methylation are confirmed, this has considerable implications for conservation and management practices aimed at promoting intermixing between populations. Both undergraduate and graduate students will participate in the project and learn a variety of techniques in molecular and evolutionary genetics.