Mating system evolution and self-incompatibility in the wild plant species Brassica cretica
(2008)- Abstract
- Compared to animals like ourselves, plants have a very flexible sexual life. Most plants are, for example, hermaphrodites with the potential capacity for reproduction by self-fertilization (or selfing). While selfing can provide several definite advantages for the individual plant, there is a downside; mainly the severe reduction in fitness due to inbreeding depression. To avoid the negative consequences of selfing, many hermaphrodite plant species have evolved an intricate self-recognition – or self-incompatibility (SI) – system that prevents fertilization by cognate pollen. SI is in the majority of cases genetically controlled by a narrowly delimited region of the genome, called the S locus. The S locus contains several tightly linked... (More)
- Compared to animals like ourselves, plants have a very flexible sexual life. Most plants are, for example, hermaphrodites with the potential capacity for reproduction by self-fertilization (or selfing). While selfing can provide several definite advantages for the individual plant, there is a downside; mainly the severe reduction in fitness due to inbreeding depression. To avoid the negative consequences of selfing, many hermaphrodite plant species have evolved an intricate self-recognition – or self-incompatibility (SI) – system that prevents fertilization by cognate pollen. SI is in the majority of cases genetically controlled by a narrowly delimited region of the genome, called the S locus. The S locus contains several tightly linked genes, two of which – SRK and SCR – determine the pistil (female) and pollen (male) SI recognition type. One of the best-characterized SI systems is found in the Brassicaceae family, which includes the model plant Arabidopsis thaliana and a number of economically important crop species of the Brassica genus, e.g. rape seed, cabbage, and turnip.
For evolutionary biologists, SI have long been a prominent and fascinating example of Darwinian natural selection acting in a frequency-dependent manner, i.e. the rarer a genetic variant becomes, the more favoured by natural selection it is. For the S locus, this means that a very large number of variants – or haplotypes – are expected to be maintained in a population and that the DNA sequences of different haplotypes will be very divergent. However, until recently there has been a shortage of empirical studies from natural plant populations to test these, and other, theoretical predictions of S locus evolutionary dynamics.
In this thesis, I have produced the largest SRK and SCR DNA sequence data set from a wild Brassica species available to date. These data have allowed me to explore, in more detail than previously possible, the population genetic properties and the evolutionary history of the Brassica S locus. Moreover, accompanying studies of the pattern of inheritance of S locus variants and the occurrence of self-fertilization in natural B. cretica population have added novel information of great value to the understanding of how plants produce offspring in nature. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1148019
- author
- Aaltonen, Kristina LU
- supervisor
-
- Alf Ceplitis LU
- Torbjörn Säll LU
- opponent
-
- Prof. Dr. van Tienderen, Peter H., University of Amsterdam
- organization
- publishing date
- 2008
- type
- Thesis
- publication status
- published
- subject
- keywords
- mating system, Brassicaceae, Brassica cretica, recombination, frequency-dependent selection, evolution, population structure, segregation distortion, SCR, self-incompatibility, SRK
- pages
- 142 pages
- defense location
- Genetikhusets föreläsningssal, Sölvegatan 29, Lund
- defense date
- 2008-05-31 10:00:00
- ISBN
- 978-91-85067-41-1
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Department of Cell and Organism Biology (Closed 2011.) (011002100)
- id
- 60d4254f-c22a-44b1-90fc-c4b4425e91bb (old id 1148019)
- date added to LUP
- 2016-04-04 14:42:13
- date last changed
- 2018-11-21 21:22:15
@phdthesis{60d4254f-c22a-44b1-90fc-c4b4425e91bb, abstract = {{Compared to animals like ourselves, plants have a very flexible sexual life. Most plants are, for example, hermaphrodites with the potential capacity for reproduction by self-fertilization (or selfing). While selfing can provide several definite advantages for the individual plant, there is a downside; mainly the severe reduction in fitness due to inbreeding depression. To avoid the negative consequences of selfing, many hermaphrodite plant species have evolved an intricate self-recognition – or self-incompatibility (SI) – system that prevents fertilization by cognate pollen. SI is in the majority of cases genetically controlled by a narrowly delimited region of the genome, called the S locus. The S locus contains several tightly linked genes, two of which – SRK and SCR – determine the pistil (female) and pollen (male) SI recognition type. One of the best-characterized SI systems is found in the Brassicaceae family, which includes the model plant Arabidopsis thaliana and a number of economically important crop species of the Brassica genus, e.g. rape seed, cabbage, and turnip.<br/><br> <br/><br> For evolutionary biologists, SI have long been a prominent and fascinating example of Darwinian natural selection acting in a frequency-dependent manner, i.e. the rarer a genetic variant becomes, the more favoured by natural selection it is. For the S locus, this means that a very large number of variants – or haplotypes – are expected to be maintained in a population and that the DNA sequences of different haplotypes will be very divergent. However, until recently there has been a shortage of empirical studies from natural plant populations to test these, and other, theoretical predictions of S locus evolutionary dynamics.<br/><br> <br/><br> In this thesis, I have produced the largest SRK and SCR DNA sequence data set from a wild Brassica species available to date. These data have allowed me to explore, in more detail than previously possible, the population genetic properties and the evolutionary history of the Brassica S locus. Moreover, accompanying studies of the pattern of inheritance of S locus variants and the occurrence of self-fertilization in natural B. cretica population have added novel information of great value to the understanding of how plants produce offspring in nature.}}, author = {{Aaltonen, Kristina}}, isbn = {{978-91-85067-41-1}}, keywords = {{mating system; Brassicaceae; Brassica cretica; recombination; frequency-dependent selection; evolution; population structure; segregation distortion; SCR; self-incompatibility; SRK}}, language = {{eng}}, school = {{Lund University}}, title = {{Mating system evolution and self-incompatibility in the wild plant species Brassica cretica}}, year = {{2008}}, }