McQueen, Eden
(2021)
Correlation or Coevolution? Investigating the Genetic Architecture of Male and Female Genitalia in the Drosophila melanogaster Subgroup.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
To understand the evolution of organismal traits, one must consider that not all traits are fully independent at the developmental level. This lack of independence can result from several mechanisms, one of which is gene regulatory network (GRN) re-use. Novel developmental outcomes resulting from the redeployment of existing GRNs may be advantageous if these outcomes are adaptive. However, because redeployed developmental networks are shared by multiple traits, GRN reuse also act as a constraint if lacking trait independence is detrimental. In my doctoral work, I investigated trait integration and GRN reuse (network co-option), in two ways. In Chapter one, I explore of the phenomenon of network co-option from a theoretical standpoint. I discuss the various forms that network co-option can take, as well as the possible consequences of network co-option with regard to evolution. In Chapter two, I use novel morphological structures in the male and female genitalia of the Drosophila melanogaster subgroup as an empirical case study. The male structure, the posterior lobe, and the female structure, the oviscapt pouch, arose concomitantly in this lineage, and are correlated in size across species. Male and female genitalia develop from serially homologous segments and share some of their developmental programming, suggesting that the novel traits may also be developmentally linked. We performed a QTL analysis of the posterior lobe and oviscapt pouch using two species in this group (D. simulans and D. mauritiana), and found that many loci associated with the size divergence of these two traits occur in the same genomic intervals. While further experimental work will determine whether loci responsible for the male and female QTL in these regions are shared (pleiotropic) or linked, the results suggest a possible role of overlapping developmental programming in the across-species correlation. Moreover, I explore a known case of network co-option involved in the origination of the posterior lobe, and find that genes and regulatory regions of those genes from a co-opted network also show activity in the female genitalia. This is evidence that network co-option may have played a role in the concomitant appearance of these structures and their apparent coordinated evolution.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
20 January 2021 |
| Date Type: |
Publication |
| Defense Date: |
25 September 2020 |
| Approval Date: |
20 January 2021 |
| Submission Date: |
4 December 2020 |
| Access Restriction: |
2 year -- Restrict access to University of Pittsburgh for a period of 2 years. |
| Number of Pages: |
92 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Biological Sciences |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
evolution, development, genitalia, drosophila |
| Date Deposited: |
20 Jan 2021 19:00 |
| Last Modified: |
20 Jan 2023 06:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/39989 |
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