Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 9 of 9
Full-Text Articles in Life Sciences
Genetic Basis Of Hybrid Sterility Between Drosophila Pseudoobscura And D. Persimilis, Alannah J.P. Mattice
Genetic Basis Of Hybrid Sterility Between Drosophila Pseudoobscura And D. Persimilis, Alannah J.P. Mattice
Electronic Thesis and Dissertation Repository
Speciation is the underlying process that leads to formation of new species, and therefore is the basis of biodiversity. Genes involved in each stage of speciation, such as those involved in interspecies sterility, remain elusive. Male hybrid sterility and postzygotic isolation between Drosophila pseudoobscura and D. persimilis was examined in this study through backcrossing of female hybrids into each parental line (introgression), selecting for a sterile sperm phenotype, needle-eye sperm. Sperm phenotypes did not separate through backcrossing; instead, males presented with multiple sperm phenotypes. A relationship between the phenotypes observed and the potential genes involved was examined through whole genome …
The Fruitless Gene Influences Female Mate Preference In Drosophila, Tabashir A. Chowdhury
The Fruitless Gene Influences Female Mate Preference In Drosophila, Tabashir A. Chowdhury
Electronic Thesis and Dissertation Repository
Species can arise as a result of reproductive barriers that prevent gene flow between diverging populations that force them to remain isolated from one another. Behavioural isolation is one of the earliest acting reproductive barriers determined by the evolution of mating preferences that prevent inter-specific matings. Several traits have been identified that contribute to behavioural isolation, but the genetic basis of interspecific female preference is yet to be determined. I used genetic mapping techniques to identify and confirm that the fruitless gene is affecting species-specific female rejection of interspecies males, contributing to the behavioural isolation between Drosophila melanogaster and D. …
The Genetic And Environmental Basis For Chc Biosynthesis In Drosophila, Heather Ke Ward
The Genetic And Environmental Basis For Chc Biosynthesis In Drosophila, Heather Ke Ward
Electronic Thesis and Dissertation Repository
Cuticular hydrocarbons (CHCs) are produced by insects and primarily used to prevent desiccation. In Drosophila, certain compounds have secondary roles as infochemicals that may act during courtship to influence mate choice. Certain CHCs may stimulate courtship with heterospecifics or act to repel conspecifics. The CHC profile produced by an individual is the result of the interaction between its genetic background and the environment, though the genes that underlie species differences in CHC production and how the environment can modulate the abundance of individual compounds within a species is not well known. Here, candidate gene CG5946 was found to be …
Investigating The Role Of Fruitless In Behavioural Isolation Between Drosophila Melanogaster And Drosophila Simulans, Jalina Bielaska Da Silva
Investigating The Role Of Fruitless In Behavioural Isolation Between Drosophila Melanogaster And Drosophila Simulans, Jalina Bielaska Da Silva
Electronic Thesis and Dissertation Repository
Behavioural isolation is a prezygotic mechanism that is usually determined by female preference, such as seen with the rejection behaviour exhibited by Drosophila simulans females to D. melanogaster males. To confirm the role of a previously identified candidate gene fruitless (fru) in behavioural isolation, I proposed to disrupt fru expression in both D. melanogaster and D. simulans to allow for the generation of interspecies hybrids expressing only a species-specific allele of fru. A reciprocal hemizygosity test would then be used to confirm the role of fru in behavioural isolation. Disruptions of fru in both D. melanogaster and …
Cellular/Molecular Analysis Of Interspecies Sterile Male Hybrids In Drosophila, Rachelle L. Kanippayoor
Cellular/Molecular Analysis Of Interspecies Sterile Male Hybrids In Drosophila, Rachelle L. Kanippayoor
Electronic Thesis and Dissertation Repository
Over time, genetic differences can accumulate between populations that are geographically separated. This genetic divergence can lead to the evolution of reproductive isolating mechanisms that reduce gene flow between the populations and, upon secondary contact, result in distinct species. The process of speciation is, thus, what accounts for the multitude of species that contribute to the rich biodiversity on Earth. Interspecies hybrid sterility is a postzygotic isolating mechanism that affects the development of hybrids, rendering them sterile. A notable trend, known as Haldane's Rule, describes that heterogametic individual (e.g. males in Drosophila) are more susceptible to sterility than homogametic …
Genetics Of Female Interspecific Mate Rejection In Species Of Drosophila, Ryan Calhoun
Genetics Of Female Interspecific Mate Rejection In Species Of Drosophila, Ryan Calhoun
Electronic Thesis and Dissertation Repository
Speciation can occur when accumulated differences in mating behavior force diverging species to remain reproductively isolated from one another. A key determinant of behavioural isolation is the evolution of female mating preferences that prevent interspecific males from mating. However, no individual genes involved in species-specific preferences of females have yet been identified. Using various genetic mapping techniques available for studying strains and species of Drosophila, I identify candidate genes involved in D. simulans female discrimination against D. melanogaster males. One candidate gene in particular, Katanin-60, was selected for further characterization. Katanin-60 is a gene encoding a microtubule severing …
Foraging Ecology, Sexual Selection, And Divergence In Sunfish (Lepomis Spp.), Scott F. Colborne
Foraging Ecology, Sexual Selection, And Divergence In Sunfish (Lepomis Spp.), Scott F. Colborne
Electronic Thesis and Dissertation Repository
The origins of novel traits and their contribution to biodiversity have long been of interest to biologists. My research focused on the links between foraging ecology and both natural and sexual selection, and how these mechanisms interact to shape the phenotypic diversification of natural populations. Using bluegill (Lepomis macrochirus) and pumpkinseed sunfish (Lepomis gibbosus), I examined three major questions: 1) how are diet and morphological variation related to alternative reproductive tactics in bluegill; 2) are sexual selection and disruptive selection driving divergence between foraging ecomorphs in pumpkinseed; and 3) how are human-induced changes to prey communities …
Reproductive Biology And Speciation In Drosophila Pseudoobscura, Josh H.M. Alpern
Reproductive Biology And Speciation In Drosophila Pseudoobscura, Josh H.M. Alpern
Electronic Thesis and Dissertation Repository
Sexual selection is an important force driving the evolution of reproductive traits, including sperm morphology and mating behaviour. Divergent sexual selection among populations can eventually lead to errors in spermatogenesis in inter-population hybrids, and subsequently speciation. In Chapter 2, I identify a novel sperm class and how its proportion in the ejaculate is adjusted when Drosophila pseudoobscura males are exposed to competition. In Chapter 3, I assess how competition causes both males and females to adjust their mating behaviour. In Chapter 4, I characterize interspecific hybrid spermatogenic breakdown from two closely-related sub-species. While the genetics of hybrid sterility has been …
Postzygotic Isolation In Drosophila Simulans And D. Mauritiana, Christopher T. D. Dickman
Postzygotic Isolation In Drosophila Simulans And D. Mauritiana, Christopher T. D. Dickman
Electronic Thesis and Dissertation Repository
The study of speciation requires examination of barriers that produce and maintain species separation. Using Drosophila simulans and D. mauritiana, this thesis focuses on post-zygotic isolating mechanisms, which occur after the formation of interspecies hybrids. This study aims to examine the genetic causes of male hybrid sterility and decreased hybrid female lifespan. Quantitative trait locus (QTL) mapping using flies with an attached-X chromosome, identified seven autosomal QTLs that contribute to hybrid sterility. Separately, reduction in hybrid female lifespan was noted for females bearing an attached-X chromosome and was more severe in individuals who were mated. This reduction is caused …