Evidence for adaptive variation at the genes coding for cytosolic phosphoglucose isomerase (PGIC) in Festuca ovina L.
Författare
Summary, in Swedish
Popular Abstract in English
Darwin’s masterpiece “On the origin of species” describes how populations (one group of individuals from the same species that can easily mate with each other and that occupy the same geographic area) evolve through the process of natural selection, which can be shortly abbreviated as the survival of the fittest. More specifically, the individuals within one population may vary significantly from each other, and much of the variation is heritable. In one environment, compared to the less fitted individuals, those fitted ones have a higher chance to survive, to reproduce and therefore to pass on their heritable, beneficial traits to the next generation. As a result of this natural selection process, the fitted individuals’ heritable, beneficial traits will become more common in their favorable environment, which will lead to one of the typical signatures of natural selection: the associations between the heritable, beneficial traits and the favorable environment. The action of natural selection may also leave its signature on the genetic materials of DNA that underlies the heritable traits.
In the present thesis, I focus on one common grass species Festuca ovina L. (common name: sheep’s fescue) in the alvar grassland of Öland (Sweden). On Öland, sheep’s fescue is one of the few species that survive through the full range of alvar grassland that varies significantly in its environmental conditions.
Earlier field surveys of enzyme (product of the molecular unit of DNA, gene) variation in sheep’s fescue on Öland showed significant association between the variation at one cytosolic enzyme phosphoglucose isomerase (PGI) that is fundamental to almost all life and the environment variation, suggesting natural selection on PGI variation.
In the present thesis, we explored further the suggested selection on PGI variation and we found signatures of natural selection at two genes (PgiC1 and PgiC2( f )) that encode (determine) PGI in sheep’s fescue. PgiC1 is regarded to be native to sheep’s fescue while PgiC2( f ) is suggested to be acquired from other related species.
At the PgiC1 gene, analyses of the DNA variation revealed signatures of selection at two codons (encoding unit of DNA). The two codons being under selection is also suggested by the identified association between the variation at these two codons and the environment variation on Öland.
At the PgiC2( f ) gene that was only found in some sheep’s fescue individuals, we have also observed an association between the presence/absence of this gene and the environment variation on Öland, suggesting selection on PgiC2( f ).
In summary, we acquired a better understanding of the natural selection on the PGI variation in sheep’s fescue, and our study represents the first study that has clearly demonstrated the signature of natural selection at more than one cytosolic Pgi genes (two variants of which are PgiC1 and PgiC2( f )) within one single species.
Darwin’s masterpiece “On the origin of species” describes how populations (one group of individuals from the same species that can easily mate with each other and that occupy the same geographic area) evolve through the process of natural selection, which can be shortly abbreviated as the survival of the fittest. More specifically, the individuals within one population may vary significantly from each other, and much of the variation is heritable. In one environment, compared to the less fitted individuals, those fitted ones have a higher chance to survive, to reproduce and therefore to pass on their heritable, beneficial traits to the next generation. As a result of this natural selection process, the fitted individuals’ heritable, beneficial traits will become more common in their favorable environment, which will lead to one of the typical signatures of natural selection: the associations between the heritable, beneficial traits and the favorable environment. The action of natural selection may also leave its signature on the genetic materials of DNA that underlies the heritable traits.
In the present thesis, I focus on one common grass species Festuca ovina L. (common name: sheep’s fescue) in the alvar grassland of Öland (Sweden). On Öland, sheep’s fescue is one of the few species that survive through the full range of alvar grassland that varies significantly in its environmental conditions.
Earlier field surveys of enzyme (product of the molecular unit of DNA, gene) variation in sheep’s fescue on Öland showed significant association between the variation at one cytosolic enzyme phosphoglucose isomerase (PGI) that is fundamental to almost all life and the environment variation, suggesting natural selection on PGI variation.
In the present thesis, we explored further the suggested selection on PGI variation and we found signatures of natural selection at two genes (PgiC1 and PgiC2( f )) that encode (determine) PGI in sheep’s fescue. PgiC1 is regarded to be native to sheep’s fescue while PgiC2( f ) is suggested to be acquired from other related species.
At the PgiC1 gene, analyses of the DNA variation revealed signatures of selection at two codons (encoding unit of DNA). The two codons being under selection is also suggested by the identified association between the variation at these two codons and the environment variation on Öland.
At the PgiC2( f ) gene that was only found in some sheep’s fescue individuals, we have also observed an association between the presence/absence of this gene and the environment variation on Öland, suggesting selection on PgiC2( f ).
In summary, we acquired a better understanding of the natural selection on the PGI variation in sheep’s fescue, and our study represents the first study that has clearly demonstrated the signature of natural selection at more than one cytosolic Pgi genes (two variants of which are PgiC1 and PgiC2( f )) within one single species.
Avdelning/ar
Publiceringsår
2015
Språk
Engelska
Dokumenttyp
Doktorsavhandling
Förlag
Department of Biology, Lund University
Ämne
- Biological Sciences
Nyckelord
- 3-D protein structure
- purifying selection
- positive selection
- cDNA sequences
- local adaptation
- alvar grasslands
- Festuca ovina
- Phosphoglucose isomerase
- PgiC loci
- SNPs
- nucleotide polymorphism
- horizontal gene transfer
Status
Published
Handledare
- Honor C. Prentice
- Anders Tunlid
- Bengt Hansson
ISBN/ISSN/Övrigt
- ISBN: 978-91-7623-344-3
Försvarsdatum
29 maj 2015
Försvarstid
13:00
Försvarsplats
Blue Hall, Ecology Building, Sölvegatan 37, Lund
Opponent
- Christopher Wheat