525
variants at the same sets of genes involved in AHR response but also show evidence of selection at population- specific genomic locations associated with pollution tolerance as well (Reid et al. 2016). Taken as a whole, these studies suggest
that tolerance to chronic exposure can evolve rapidly and repeatedly in these systems but requires adequate potential adaptive variation to begin with (Whitehead
et al. 2017), a result that emphasizes the need to maintain/monitor genomic diversity to promote resilience in wild populations. Because of the AHR pathway’s
involvement in numerous fundamental cellular processes, resistance may come
with a cost to absolute fitness and could potentially adversely affect populations by
impacting fecundity, changing behavior, decreasing growth, and/or impairing the
immune responses (Meyer and Di Giulio 2003; Frederick et al. 2007). Studies of
copepods and Gulf killifish after the DWH oil spill have noted functional changes,
similar to those seen in chronically impacted populations (Whitehead et al. 2012b;
Lee et al. 2017), but long-term study will be needed to determine if these are permanent evolutionary changes.
30.5 Conclusions
Studies involving transcriptomics, epigenetics, and population genomics can provide information on organismal response to exposure across time scales from
immediate to generational. These techniques compliment laboratory-based exposure experiments designed at evaluating lethality and impairment following exposure and provide a link for understanding how organismal response and
population-level response are related. An important legacy of DWH oil spill
research will be an increased understanding of the types of impacts acute oil exposure has on organisms in controlled laboratory settings, and molecular studies have
been a vital component of that research. However, the results from laboratory
experiments still need to be compared to observations made in wild populations
across a variety of taxa. These field-based follow-up studies, which are ongoing,
will not only provide valuable information on population response and resiliency
but should aid in the development of novel biomarkers of oil exposure. Further,
anthropogenic selection pressure, including exposure to hydrocarbons, has become
omnipresent across ecosystems, and continued studies are needed to assess and
understand patterns of evolutionary change, especially in living resources upon
which humans depend.
Funding Information This research was made possible by grants from the Gulf of Mexico
Research Initiative through its consortia: The Center for the Integrated Modeling and Analysis of
the Gulf Ecosystem (C-IMAGE) and Relationships of Effects of Cardiac Outcomes in fish for
Validation of Ecological Risk (RECOVER).
30 Genetics and Oil: Transcriptomics, Epigenetics, and Population Genomics as Tools…
variants at the same sets of genes involved in AHR response but also show evidence of selection at population- specific genomic locations associated with pollution tolerance as well (Reid et al. 2016). Taken as a whole, these studies suggest
that tolerance to chronic exposure can evolve rapidly and repeatedly in these systems but requires adequate potential adaptive variation to begin with (Whitehead
et al. 2017), a result that emphasizes the need to maintain/monitor genomic diversity to promote resilience in wild populations. Because of the AHR pathway’s
involvement in numerous fundamental cellular processes, resistance may come
with a cost to absolute fitness and could potentially adversely affect populations by
impacting fecundity, changing behavior, decreasing growth, and/or impairing the
immune responses (Meyer and Di Giulio 2003; Frederick et al. 2007). Studies of
copepods and Gulf killifish after the DWH oil spill have noted functional changes,
similar to those seen in chronically impacted populations (Whitehead et al. 2012b;
Lee et al. 2017), but long-term study will be needed to determine if these are permanent evolutionary changes.
30.5 Conclusions
Studies involving transcriptomics, epigenetics, and population genomics can provide information on organismal response to exposure across time scales from
immediate to generational. These techniques compliment laboratory-based exposure experiments designed at evaluating lethality and impairment following exposure and provide a link for understanding how organismal response and
population-level response are related. An important legacy of DWH oil spill
research will be an increased understanding of the types of impacts acute oil exposure has on organisms in controlled laboratory settings, and molecular studies have
been a vital component of that research. However, the results from laboratory
experiments still need to be compared to observations made in wild populations
across a variety of taxa. These field-based follow-up studies, which are ongoing,
will not only provide valuable information on population response and resiliency
but should aid in the development of novel biomarkers of oil exposure. Further,
anthropogenic selection pressure, including exposure to hydrocarbons, has become
omnipresent across ecosystems, and continued studies are needed to assess and
understand patterns of evolutionary change, especially in living resources upon
which humans depend.
Funding Information This research was made possible by grants from the Gulf of Mexico
Research Initiative through its consortia: The Center for the Integrated Modeling and Analysis of
the Gulf Ecosystem (C-IMAGE) and Relationships of Effects of Cardiac Outcomes in fish for
Validation of Ecological Risk (RECOVER).
30 Genetics and Oil: Transcriptomics, Epigenetics, and Population Genomics as Tools…