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Patterns of differentiation in a colour polymorphism and in neutral markers reveal rapid genetic changes in natural damselfly populations

Abbott, J. K.; Bensch, Staffan LU ; Gosden, Thomas LU and Svensson, Erik LU (2008) In Molecular Ecology 17(6). p.1597-1604
Abstract
The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F-ST values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F-ST (selected) > F-ST (neutralfl, or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [FST (selected) < F-ST (neutral)]. Here, we compared F-ST values for putatively neutral data (obtained using amplified... (More)
The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F-ST values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F-ST (selected) > F-ST (neutralfl, or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [FST (selected) < F-ST (neutral)]. Here, we compared F-ST values for putatively neutral data (obtained using amplified fragment length polymorphism) with estimates of differentiation in morph frequencies in the colour-polymorphic damselfly Ischnura elegans. We found that in the first year (2000), population differentiation in morph frequencies was significantly greater than differentiation in neutral loci, while in 2002 (only 2 years and 2 generations later), population differentiation in morph frequencies had decreased to a level significantly lower than differentiation in neutral loci. Genetic drift as an explanation for population differentiation in morph frequencies could thus be rejected in both years. These results indicate that the type and/or strength of selection on morph frequencies in this system can change substantially between years. We suggest that an approach to a common equilibrium morph frequency across all populations, driven by negative frequency-dependent selection, is the cause of these temporal changes. We conclude that inferences about selection obtained by comparing F-ST values from neutral and adaptive genetic variation are most useful when spatial and temporal data are available from several populations and time points and when such information is combined with other ecological sources of data. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
AFLP, frequency dependence, genetic, drift, population divergence, non-equilibrium conditions, extinction-recolonization dynamics
in
Molecular Ecology
volume
17
issue
6
pages
1597 - 1604
publisher
Wiley-Blackwell
external identifiers
  • wos:000254703000019
  • scopus:40449123128
ISSN
0962-1083
DOI
10.1111/j.1365-294X.2007.03641.x
language
English
LU publication?
yes
id
8ecd41ef-4963-484f-a04b-e5e6791c9d19 (old id 1207421)
date added to LUP
2008-08-27 13:37:27
date last changed
2017-09-10 03:44:20
@article{8ecd41ef-4963-484f-a04b-e5e6791c9d19,
  abstract     = {The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F-ST values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F-ST (selected) &gt; F-ST (neutralfl, or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [FST (selected) &lt; F-ST (neutral)]. Here, we compared F-ST values for putatively neutral data (obtained using amplified fragment length polymorphism) with estimates of differentiation in morph frequencies in the colour-polymorphic damselfly Ischnura elegans. We found that in the first year (2000), population differentiation in morph frequencies was significantly greater than differentiation in neutral loci, while in 2002 (only 2 years and 2 generations later), population differentiation in morph frequencies had decreased to a level significantly lower than differentiation in neutral loci. Genetic drift as an explanation for population differentiation in morph frequencies could thus be rejected in both years. These results indicate that the type and/or strength of selection on morph frequencies in this system can change substantially between years. We suggest that an approach to a common equilibrium morph frequency across all populations, driven by negative frequency-dependent selection, is the cause of these temporal changes. We conclude that inferences about selection obtained by comparing F-ST values from neutral and adaptive genetic variation are most useful when spatial and temporal data are available from several populations and time points and when such information is combined with other ecological sources of data.},
  author       = {Abbott, J. K. and Bensch, Staffan and Gosden, Thomas and Svensson, Erik},
  issn         = {0962-1083},
  keyword      = {AFLP,frequency dependence,genetic,drift,population divergence,non-equilibrium conditions,extinction-recolonization dynamics},
  language     = {eng},
  number       = {6},
  pages        = {1597--1604},
  publisher    = {Wiley-Blackwell},
  series       = {Molecular Ecology},
  title        = {Patterns of differentiation in a colour polymorphism and in neutral markers reveal rapid genetic changes in natural damselfly populations},
  url          = {http://dx.doi.org/10.1111/j.1365-294X.2007.03641.x},
  volume       = {17},
  year         = {2008},
}