DISSERTATION RESEARCH: Olfactory reproductive isolating mechanisms in swordtail fishes

Texas A&M University, College Station TX

Investigators

Abstract

Swordtails (Xiphophorus) are live-bearing fishes native to Central America and they are excellent models for studying animal behavior, especially mate choice. In many swordtails, males have an elongated ornament on their tail fins called a "sword", which has evolved in response to female mating preferences. Females also prefer the smell (pheromone) of males of their own species. Recent studies revealed that olfactory preference is either positively or negatively affected by early learning experience, depending on the species. X. malinche, for example, dislike the familiar male smell while its sister species X. birchmanni prefers it. Animals smell thanks to olfactory cells in their noses, which express odorant receptor genes, each specific to a particular set of molecules. There are about 200 types of odorant receptor genes in a Xiphophorus. This study will use high-throughput DNA sequencing to look at how many copies of each odorant receptor gene are expressed in the fish exposed to different adult species early in life. By comparing the expression patterns across the three experimental groups, we will try to pinpoint candidate receptors that are specialized for detecting species-specific pheromone cues. Broader impacts: This study can help us understand how learning and brain development work at a molecular level. During this project, one to two undergraduate students will be trained in biological computing and programming. Popular articles will continue to be contributed to Fishchum (http://fishchum.okstate.edu/), a web platform connecting fish biologists and aquarists. The findings from these studies will reach a multilingual audience as articles will be written in English, Chinese and Spanish and some findings will be used for outreach via popular hobbyist websites and/or magazines.