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Reverse Evolution of Armor Plates in the Threespine Stickleback

Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Current Biology (Impact Factor: 9.92). 06/2008; 18(10):769-74. DOI: 10.1016/j.cub.2008.04.027
Source: PubMed

ABSTRACT Faced with sudden environmental changes, animals must either adapt to novel environments or go extinct. Thus, study of the mechanisms underlying rapid adaptation is crucial not only for the understanding of natural evolutionary processes but also for the understanding of human-induced evolutionary change, which is an increasingly important problem [1-8]. In the present study, we demonstrate that the frequency of completely plated threespine stickleback fish (Gasterosteus aculeatus) has increased in an urban freshwater lake (Lake Washington, Seattle, Washington) within the last 40 years. This is a dramatic example of "reverse evolution,"[9] because the general evolutionary trajectory is toward armor-plate reduction in freshwater sticklebacks [10]. On the basis of our genetic studies and simulations, we propose that the most likely cause of reverse evolution is increased selection for the completely plated morph, which we suggest could result from higher levels of trout predation after a sudden increase in water transparency during the early 1970s. Rapid evolution was facilitated by the existence of standing allelic variation in Ectodysplasin (Eda), the gene that underlies the major plate-morph locus [11]. The Lake Washington stickleback thus provides a novel example of reverse evolution, which is probably caused by a change in allele frequency at the major plate locus in response to a changing predation regime.

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    • "Adaptation occurs due to selection on standing variation or de novo mutations. Adaptation from standing variation has been well-described in a number of systems; for example, selection for lactose tolerance in humans (Plantinga et al., 2012; Tishkoff et al., 2007), variation at the Eda locus in three-spined stickleback (Kitano et al., 2008; Colosimo et al., 2005), and pupal diapause in the Apple Maggot fly (Feder et al., 2003). Although the adaptive role of standing variation has been described in many systems, its importance in domestication is not as well studied. "
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    PeerJ 04/2015; 3:e900. DOI:10.7717/peerj.900 · 2.10 Impact Factor
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    • "y changes in the genetic composition of populations that occurred over dec - ades and impossible for changes in phenotypic composi - tion . Here , well - curated specimen and tissue collections have repeatedly been shown to be of great value for detect - ing and documenting contemporary phenotypic ( Suarez and Tsutsui 2004 ; Carroll et al . 2005 ; Kitano et al . 2008 ) and genetic changes ( Wandeler et al . 2007 ) . Whitefish ( Coregonus spp . , Fig . 1J ) are one of the most extensively diversified fish in large and deep lakes of the Northern Hemisphere ( Turgeon and Bernatchez 2003 ; Hudson et al . 2011 ) . In the archipelago of large and deep pre - Alpine lakes on the north slope of the European "
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    • "In fact, although the reduction in body armour in freshwater populations compared to marine populations is very common across the stickleback's distribution range, it is not the only pattern observed. Several freshwater populations remain completely plated or evolve only weak armour reduction (Hagen & Gilbertson 1972; Hagen & Moodie 1982; Baumgartner & Bell 1984; Banbura 1994; Klepaker 1995; Bell 2001; McCairns & Bernatchez 2008, 2012; Berner et al. 2010; Lucek et al. 2010; Leinonen et al. 2012; Moser et al. 2012), or might even show reverse evolution for plate number (Kitano et al. 2008). Likewise, marine and estuarine populations may be highly variable in plate number as well (Banbura 1994; Klepaker 1996; Raeymaekers et al. 2007). "
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