DISSERTATION RESEARCH: The Origin and Evolution of Recently Gained Introns in Daphnia Populations

Indiana University, Bloomington IN

Investigators

Abstract

Introns are noncoding DNA sequences that interrupt genes in higher organisms, and are removed prior to the manufacture of a protein. Some species have just a couple of introns in their entire genome, and others have many introns inserted into almost every gene. The causes of these differences are unknown despite much prior work on the subject, and solving the problem remains a major challenge for evolutionary genetics. Currently, we know very little about how new introns arise; this is because in nearly all species that have been studied, all the introns are of ancient origin. Active loss and gain of introns is known in only one species, the waterflea Daphnia pulex. The PIs will conduct genomic analyses of this species and a related one in which introns are stable. They will use extensive surveys of populations at the genomic level to learn where the new introns come from, the mechanisms of insertion, whether newly inserted introns persist, and rates at which new introns arise and are lost. This project has a high likelihood of substantially improving our understanding of the origin, mechanisms, and fates of new introns in Daphnia - results that will be applicable to higher organisms in general. The PIs will mentor undergraduates through independent supervised projects using molecular bench work and bioinformatic analyses, as well as giving the students opportunities to develop communication skills. This research will also provide opportunities for international collaboration.