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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Eric R. Fetherman</dc:contributor>
  <dc:contributor>Dana L. Winkelman</dc:contributor>
  <dc:contributor>Melinda R. Baerwald</dc:contributor>
  <dc:creator>Brian W. Avila</dc:creator>
  <dc:date>2025</dc:date>
  <dc:description>&lt;p&gt;Introduction: &lt;i&gt;Myxobolus cerebralis&lt;/i&gt;&lt;span&gt;, the parasite responsible for salmonid whirling disease, was unintentionally introduced to and became established in Colorado in the 1990s. Mortality of young-of-year fish due to infection by&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. cerebralis&lt;/i&gt;&lt;span&gt;&amp;nbsp;resulted in recruitment failure and subsequent significant declines in Rainbow Trout (&lt;/span&gt;&lt;i&gt;Oncorhynchus mykiss&lt;/i&gt;&lt;span&gt;) populations. The complex multistage lifecycle of&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. cerebralis&lt;/i&gt;&lt;span&gt;&amp;nbsp;makes it difficult to eradicate and manage, and hatchery control strategies do not work in the wild. A viable method that has been utilized for wild populations is enhancing host resistance.&amp;nbsp;&lt;/span&gt;&lt;i&gt;Myxobolus cerebralis&lt;/i&gt;&lt;span&gt;&amp;nbsp;resistant Rainbow Trout were discovered at a hatchery in Germany and subsequently incorporated into Colorado's brood stock program. Since 2004,&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. cerebralis&lt;/i&gt;&lt;span&gt;&amp;nbsp;resistant strains have been stocked into all major Colorado coldwater drainages to re-establish Rainbow Trout populations after whirling disease-related declines, with documented survival and reproduction of stocked disease resistant fish.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;Methods and results: &lt;span&gt;Genetic population assignment tests (via putatively neutral microsatellite markers) were used to monitor the stocked populations and indicated that, after only a few years, many of the individuals in these populations unexpectedly assigned to genetic strains that were historically susceptible to&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. cerebralis&lt;/i&gt;&lt;span&gt;. To further investigate the genetic composition of these fish, a single nucleotide polymorphism (SNP) panel was used to determine the percent genetic composition of resistant strain in these individuals. Microsatellites and SNPs provided similar results, indicating a low percentage of ancestry from the resistant strain in these fish, but they continued to survive exposure to&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. cerebralis&lt;/i&gt;&lt;span&gt;, suggesting that these individuals possessed genetic loci necessary for resistance. Finally, a quantitative trait locus (QTL) region (termed WDRES-9) was used to identify individuals with alleles associated with disease resistance. Implementation of the WDRES-9 QTL test allowed for more accurate determination of&amp;nbsp;&lt;/span&gt;&lt;i&gt;M. cerebralis&lt;/i&gt;&lt;span&gt;&amp;nbsp;resistant individuals within wild populations and better described their variability in resistance.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.3389/ffwsc.2025.1500903</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Frontiers Media</dc:publisher>
  <dc:title>Genetics of wild, whirling disease resistant rainbow trout populations in Colorado</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>