scholarly journals What doesn’t kill them makes them stronger: An association between elongation factor 1-α overdominance in the sea star Pisaster ochraceus and "sea star wasting disease”

2016 ◽  
Author(s):  
John P. Wares ◽  
Lauren M Schiebelhut
Keyword(s):  
Pacific Coast ◽  
Functional Relationship ◽  
Elongation Factor ◽  
Sea Star ◽  
Sea Stars ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
The Relationship ◽  
Elongation Factor 1

In recent years, a massive plague has killed millions of sea stars, of many different species, along the Pacific coast of North America. This disease, known as 'sea star wasting disease' (SSWD), is thought to be caused by viral infection. In the affected sea star Pisaster ochraceus, previous work had identified that the elongation factor 1-α (EF1A) locus harbored an intronic insertion allele that is lethal when homozygous yet appears to be maintained at moderate frequency in populations through increased fitness for heterozygotes. The environmental conditions supporting this increased fitness are unknown, but overdominance is often associated with disease. Here, we evaluate populations of P. ochraceus to identify the relationship between SSWD and EF1A genotype. Our data suggest that there may be significantly decreased infection or mortality rates in individuals that are heterozygous at this locus. These results suggest further studies to understand the functional relationship between diversity at EF1A and survival in P. ochraceus.

scholarly journals What doesn’t kill them makes them stronger: an association between elongation factor 1-αoverdominance in the sea starPisaster ochraceusand “sea star wasting disease”

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1876 ◽  
Author(s):  
John P. Wares ◽  
Lauren M. Schiebelhut
Keyword(s):  
Pacific Coast ◽  
Functional Relationship ◽  
Elongation Factor ◽  
Sea Star ◽  
Sea Stars ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
The Relationship ◽  
Elongation Factor 1

In recent years, a massive mortality event has killed millions of sea stars, of many different species, along the Pacific coast of North America. This disease event, known as ‘sea star wasting disease’ (SSWD), is linked to viral infection. In one affected sea star (Pisaster ochraceus), previous work had identified that the elongation factor 1-αlocus (EF1A) harbored an intronic insertion allele that is lethal when homozygous yet appears to be maintained at moderate frequency in populations through increased fitness for heterozygotes. The environmental conditions supporting this increased fitness are unknown, but overdominance is often associated with disease. Here, we evaluate populations ofP. ochraceusto identify the relationship between SSWD and EF1A genotype. Our data suggest that there may be significantly decreased occurrence of SSWD in individuals that are heterozygous at this locus. These results suggest further studies are warranted to understand the functional relationship between diversity at EF1A and survival inP. ochraceus.

scholarly journals What doesn’t kill them makes them stronger: An association between elongation factor 1-α overdominance in the sea star Pisaster ochraceus and "sea star wasting disease”

2016 ◽  
Author(s):  
John P. Wares ◽  
Lauren M Schiebelhut
Keyword(s):  
Pacific Coast ◽  
Functional Relationship ◽  
Elongation Factor ◽  
Sea Star ◽  
Sea Stars ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
The Relationship ◽  
Elongation Factor 1

In recent years, a massive plague has killed millions of sea stars, of many different species, along the Pacific coast of North America. This disease, known as 'sea star wasting disease' (SSWD), is thought to be caused by viral infection. In the affected sea star Pisaster ochraceus, previous work had identified that the elongation factor 1-α (EF1A) locus harbored an intronic insertion allele that is lethal when homozygous yet appears to be maintained at moderate frequency in populations through increased fitness for heterozygotes. The environmental conditions supporting this increased fitness are unknown, but overdominance is often associated with disease. Here, we evaluate populations of P. ochraceus to identify the relationship between SSWD and EF1A genotype. Our data suggest that there may be significantly decreased infection or mortality rates in individuals that are heterozygous at this locus. These results suggest further studies to understand the functional relationship between diversity at EF1A and survival in P. ochraceus.

scholarly journals Is there an association between elongation factor 1-α overdominance in the seastar Pisaster ochraceus and “seastar wasting disease”?

2015 ◽  
Author(s):  
John Wares ◽  
Lauren Schiebelhut
Keyword(s):  
North America ◽  
Environmental Conditions ◽  
Pacific Coast ◽  
Elongation Factor ◽  
Mortality Rates ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
The Relationship ◽  
Elongation Factor 1

In recent years, a massive plague has killed millions of seastars, of many different species, along the Pacific coast of North America. This disease, known as 'seastar wasting disease' (SSWD), is thought to be caused by viral infection. In the affected seastar Pisaster ochraceus, previous work had identified that the elongation factor 1-α locus harbored an intronic insertion allele that is lethal when homozygous yet appears to be maintained at moderate frequency in populations through increased fitness for heterozygotes. The environmental conditions supporting this increased fitness are unknown, but overdominance is often associated with disease. Here, we evaluate seastars from 3 regional populations of P. ochraceus to identify the relationship between SSWD and genotype. Although our data suggest that there may be decreased infection or mortality rates in individuals that are heterozygous at this locus, the effect is small and not statistically significant.

scholarly journals RNA expression and disease tolerance are associated with a “keystone mutation” in the ochre sea star Pisaster ochraceus

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3696 ◽  
Author(s):  
V. Katelyn Chandler ◽  
John P. Wares
Keyword(s):  
Cellular Response ◽  
Constitutive Expression ◽  
Elongation Factor ◽  
Sea Star ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
Response To Temperature ◽  
Elongation Factor 1 ◽  
Lower Expression

An overdominant mutation in an intron of the elongation factor 1-α (EF1A) gene in the sea star Pisaster ochraceus has shown itself to mediate tolerance to “sea star wasting disease”, a pandemic that has significantly reduced sea star populations on the Pacific coast of North America. Here we use RNA sequencing of healthy individuals to identify differences in constitutive expression of gene regions that may help explain this tolerance phenotype. Our results show that individuals carrying this mutation have lower expression at a large contingent of gene regions. Individuals without this mutation also appear to have a greater cellular response to temperature stress, which has been implicated in the outbreak of sea star wasting disease. Given the ecological significance of P. ochraceus, these results may be useful in predicting the evolutionary and demographic future for Pacific intertidal communities.

scholarly journals RNA expression and disease tolerance are associated with a “keystone mutation” in the ochre sea star Pisaster ochraceus

2017 ◽  
Author(s):  
John Wares ◽  
Virginia K Chandler
Keyword(s):  
Cellular Response ◽  
Constitutive Expression ◽  
Elongation Factor ◽  
Single Mutation ◽  
Sea Star ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
Fold Reduction ◽  
Response To Temperature

An overdominant mutation in the elongation factor 1-alpha (EF1A) gene in the sea star Pisaster ochraceus has shown itself to mediate tolerance to "sea star wasting disease", a pandemic that has significantly reduced sea star populations on the Pacific coast of North America. Here we use RNA sequencing of healthy individuals to identify differences in constitutive expression of gene regions that may help explain this tolerance phenotype. Our results show that individuals carrying this single mutation have lower expression at a large contingent of gene regions, and it appears likely that the EF1A locus itself is similarly affected, with a 2-fold reduction in expression of some EF1A transcripts. Individuals without this mutation also appear to have a greater cellular response to temperature stress, which has been implicated in the outbreak of sea star wasting disease. Given the ecological significance of P. ochraceus and the key role of EF1A in cellular composition and maintenance, these results may be useful in predicting the evolutionary and demographic future for Pacific intertidal communities.

scholarly journals RNA expression and disease tolerance are associated with a “keystone mutation” in the ochre sea star Pisaster ochraceus

2017 ◽  
Author(s):  
John Wares ◽  
Virginia K Chandler
Keyword(s):  
Cellular Response ◽  
Constitutive Expression ◽  
Elongation Factor ◽  
Single Mutation ◽  
Sea Star ◽  
Wasting Disease ◽  
Pisaster Ochraceus ◽  
The Pacific ◽  
Fold Reduction ◽  
Response To Temperature

An overdominant mutation in the elongation factor 1-alpha (EF1A) gene in the sea star Pisaster ochraceus has shown itself to mediate tolerance to "sea star wasting disease", a pandemic that has significantly reduced sea star populations on the Pacific coast of North America. Here we use RNA sequencing of healthy individuals to identify differences in constitutive expression of gene regions that may help explain this tolerance phenotype. Our results show that individuals carrying this single mutation have lower expression at a large contingent of gene regions, and it appears likely that the EF1A locus itself is similarly affected, with a 2-fold reduction in expression of some EF1A transcripts. Individuals without this mutation also appear to have a greater cellular response to temperature stress, which has been implicated in the outbreak of sea star wasting disease. Given the ecological significance of P. ochraceus and the key role of EF1A in cellular composition and maintenance, these results may be useful in predicting the evolutionary and demographic future for Pacific intertidal communities.

scholarly journals Reciprocal abundance shifts of the intertidal sea stars, Evasterias troschelii and Pisaster ochraceus , following sea star wasting disease

2019 ◽  
Vol 286 (1901) ◽  
pp. 20182766 ◽  
Author(s):  
Sharon W. C. Kay ◽  
Alyssa-Lois M. Gehman ◽  
Christopher D. G. Harley
Keyword(s):  
Indirect Effects ◽  
Interference Competition ◽  
Disease Outbreaks ◽  
Ecological Communities ◽  
Population Declines ◽  
Sea Star ◽  
Sea Stars ◽  
Wasting Disease ◽  
Field Surveys ◽  
Pisaster Ochraceus

Disease emergence occurs within the context of ecological communities, and disease driven declines in host populations can lead to complex direct and indirect ecological effects. Varying effects of a single disease among multiple susceptible hosts could benefit relatively resistant species. Beginning in 2013, an outbreak of sea star wasting disease (SSWD) led to population declines of many sea star species along the west coast of North America. Through field surveys and laboratory experiments, we investigated how and why the relative abundances of two co-occurring sea star species, Evasterias troschelii and Pisaster ochraceus , shifted during the ongoing wasting epidemic in Burrard Inlet, British Columbia, Canada. We hypothesized that Evasterias is competitively inferior to Pisaster but more resistant to SSWD. Thus, we predicted that SSWD-induced declines of Pisaster could mitigate the negative effects of SSWD on Evasterias , as the latter would experience competitive release. We document shifts in sea star abundance from 2008–2017: Pisaster abundance and mean size declined during the outbreak, while Evasterias abundance increased from relatively rare to numerically dominant within the intertidal. When exposed to symptomatic sea stars, Pisaster and Evasterias both showed signs of SSWD, but transmission and susceptibility was lower in Evasterias. Despite diet overlap documented in our field surveys, Evasterias was not outcompeted by Pisaster in laboratory trails conducted with the relatively small Pisaster available after the outbreak. Interference competition with larger Pisaster , or prey exploitation by Pisaster during the summer when Evasterias is primarily subtidal, may explain the rarity of Evasterias prior to Pisaster declines. Our results suggest that indirect effects mediated by competition can mask some of the direct effects of disease outbreaks, and the combination of direct and indirect effects will determine the restructuring of a community after disturbance.

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