Speciation in three-spined stickleback
Speciation, the division of one species into two, has provided evolutionary biologists with a rich ensemble of questions, conundrums and revelations for over a century, and yet our understanding of many of the factors affecting this complex, multidimensional process remains limited. In this thesis,...
| Main Author: | |
|---|---|
| Format: | Thesis (University of Nottingham only) |
| Language: | English |
| Published: |
2018
|
| Online Access: | https://eprints.nottingham.ac.uk/52951/ |
| _version_ | 1848798845755981824 |
|---|---|
| author | Dean, Laura L. |
| author_facet | Dean, Laura L. |
| author_sort | Dean, Laura L. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Speciation, the division of one species into two, has provided evolutionary biologists with a rich ensemble of questions, conundrums and revelations for over a century, and yet our understanding of many of the factors affecting this complex, multidimensional process remains limited. In this thesis, I aimed to further our understanding of speciation using divergent populations of three-spined stickleback (Gasterosteus aculeatus) on the island of North Uist, Scottish Western Isles. Firstly, I explored the degree of morphological and genetic separation between three stickleback ecotypes, showing that both strongly reproductively isolated, and admixed populations exist in close proximity. I then attempted to identify the ecological and genetic origins of strongly isolated species-pairs, testing two competing explanations for their existence. I showed that a recent ‘double-invasion’ is unlikely, but found stark differences in the long-term genetic history between ecotypes, indicating that the evolution of species-pairs may be related to secondary contact between anciently diverged mitochondrial lineages. I then conducted mate choice trials to assess mating preferences between ecotypes, and to test for reinforcement in species-pairs. Consistent with the idea that speciation in this case is not driven purely by ecological factors, I found no evidence that reinforcement drives assortative mating in species-pairs. Rather, it appears that extant mating preferences have developed as a by-product of other adaptations. Finally, I took a brief interlude to document and investigate an exciting chance finding, internally developed embryos retained within the ovaries of a normally oviparous species, before concluding by summing up my findings, their relevance for scientific progress, and avenues opened up for further research. |
| first_indexed | 2025-11-14T20:26:15Z |
| format | Thesis (University of Nottingham only) |
| id | nottingham-52951 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T20:26:15Z |
| publishDate | 2018 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-529512025-02-28T14:11:41Z https://eprints.nottingham.ac.uk/52951/ Speciation in three-spined stickleback Dean, Laura L. Speciation, the division of one species into two, has provided evolutionary biologists with a rich ensemble of questions, conundrums and revelations for over a century, and yet our understanding of many of the factors affecting this complex, multidimensional process remains limited. In this thesis, I aimed to further our understanding of speciation using divergent populations of three-spined stickleback (Gasterosteus aculeatus) on the island of North Uist, Scottish Western Isles. Firstly, I explored the degree of morphological and genetic separation between three stickleback ecotypes, showing that both strongly reproductively isolated, and admixed populations exist in close proximity. I then attempted to identify the ecological and genetic origins of strongly isolated species-pairs, testing two competing explanations for their existence. I showed that a recent ‘double-invasion’ is unlikely, but found stark differences in the long-term genetic history between ecotypes, indicating that the evolution of species-pairs may be related to secondary contact between anciently diverged mitochondrial lineages. I then conducted mate choice trials to assess mating preferences between ecotypes, and to test for reinforcement in species-pairs. Consistent with the idea that speciation in this case is not driven purely by ecological factors, I found no evidence that reinforcement drives assortative mating in species-pairs. Rather, it appears that extant mating preferences have developed as a by-product of other adaptations. Finally, I took a brief interlude to document and investigate an exciting chance finding, internally developed embryos retained within the ovaries of a normally oviparous species, before concluding by summing up my findings, their relevance for scientific progress, and avenues opened up for further research. 2018-12-13 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/52951/1/Laura%20Dean%204240310.pdf Dean, Laura L. (2018) Speciation in three-spined stickleback. PhD thesis, University of Nottingham. |
| spellingShingle | Dean, Laura L. Speciation in three-spined stickleback |
| title | Speciation in three-spined stickleback |
| title_full | Speciation in three-spined stickleback |
| title_fullStr | Speciation in three-spined stickleback |
| title_full_unstemmed | Speciation in three-spined stickleback |
| title_short | Speciation in three-spined stickleback |
| title_sort | speciation in three-spined stickleback |
| url | https://eprints.nottingham.ac.uk/52951/ |