Pleiotropic Effects of Natural Genetic Variation in Drosophila Melanogaster on Fitness
Creators: name: Hodges, Theresa Kathleen
Publisher: name: Maryland Shared Open Access Repository
Year: 2010
Subjects: Balancing selection
behavior
Drosophila
genetic variation
immune response
parasitoids

description: Pleiotropic genes can influence the course of evolution by producing correlated responses to selection and potentially hindering adaptive evolution if alternative alleles have antagonistic effects on fitness traits. Little is known about the pleiotropic effects of natural variation in any gene on fitness and the selective agents acting on this variation. In this thesis, I examined the pleiotropic effects of natural variation in the Dopa decarboxylase alic&gt;Ddc e of Drosophila melanogaster how that natural Ddc polymorphism ciated with life span variation has pleiotropic effects on larval defenses against parasitoid wasps, larval foraging behavior, and larval feeding rates. I measured these traits because Ddc lyzes the production of two neurotransmitters, dopamine and serotonin, which have known effects on behavior and immunity in invertebrates and vertebrates. Homozygote and heterozygote effects of two Ddc les with opposing life spans were measured for each larval trait. Larvae homozygous or heterozygous for the long-lived Ddc le had a better immune response against the parasitoid, Aphaereta sp t were parasitized more by Leptopilina boulardi  larvae homozygous for the short-lived Ddc le. Similar differences in parasitism avoidance were found when larvae with different Ddc types were exposed to natural rates of parasitism by L. boulardi he field, confirming the ecological relevance of the Ddc morphism. Larvae with the long-lived Ddc le moved shorter distances while foraging and fed slower than larvae homozygous for the short-lived Ddc le, which supports a known trade off between immune resistance and larval competitive ability. Heterozygous larvae have higher levels of dopamine than larvae homozygous for the short-lived Ddc le suggesting thatDdc morphism has functional consequences for the observed phenotypic variation. I also conducted a multi-year field study (2004-2006) to investigate the interrelationships between Drosophila its parasitoids in two natural populations in the Baltimore, MD area, which allowed documentation of ecological variables that may select for differences in larval fitness traits influenced by Ddc scri&gt;  10360&lt;&gt;  application:pdf&lt;&gt;  en&lt;&gt;  UMBC Thesis and Dissertations.&lt;&gt;  This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. for permission to publish or reproduce, please see http://aok.lib.umbc.edu/specoll/repro.php or contact Special Collections at speccoll(at)umbc.edu.&lt;&gt;  &lt;&gt;  Hodges_umbc_0434D_10360.pdf&lt;&gt;  Access limited to the UMBC community.  Item may possibly be obtained via Interlibrary Loan through a local library, pending author/copyright holder's permission.&lt;&gt;  ip:129.2.19.84; ip:129.2.19.100; ip:130.85.0-56.*; ip:130.85.58-255.*; deny:file&lt;  &lt;  &lt;  24391.pdf&lt; 2011-08-11&lt;  2013-10-17&lt;  24391&lt;