{"id":12252,"date":"2020-03-01T21:57:12","date_gmt":"2020-03-01T21:57:12","guid":{"rendered":"https:\/\/www.environment-hawaii.org\/?p=12252"},"modified":"2020-03-01T21:58:57","modified_gmt":"2020-03-01T21:58:57","slug":"can-genetic-engineering-save-the-iiwi-scientists-in-volcano-weigh-the-odds","status":"publish","type":"post","link":"https:\/\/environment-hawaii.org\/?p=12252","title":{"rendered":"Can Genetic Engineering Save the \u2018I\u2018iwi? Scientists in Volcano Weigh the Odds"},"content":{"rendered":"\n
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Temperatures are rising. And as they soar, so, too, do the mosquitoes that carry the parasite that causes avian malaria, fatal to so many of the native Hawaiian forest birds.<\/p>\n\n\n\n

For years, scientists and biologists concerned with the health of forest bird populations have struggled to address the problem of avian malaria, a major factor in wiping out most native birds from lowland forests. But now, as the impacts of global warming accelerate, the forests that have become refugia for \u2018i\u2018iwi and other native birds that are extremely vulnerable to malaria are in danger of losing that status. Warmer conditions will allow mosquitoes to invade mid- and high-elevation forests, resulting in the spread of malaria infection to the last remaining populations of many of the most threatened bird species on the planet.<\/p>\n\n\n\n

To address this, current approaches include reducing mosquito habitat through fencing and the removal of feral animals that create wallows where mosquitoes can breed and efforts to infect male mosquitoes with a strain of the Wolbachia bacterium that makes them infertile when they mate with females in the wild.<\/p>\n\n\n\n

But what if the birds could be made resistant to malaria through genetic engineering?<\/p>\n\n\n\n

That was the question that scientists from the University of Wisconsin- Madison and the U.S. Geological Survey\u2019s Pacific Island Ecosystems Research\u00a0Center in Volcano addressed in research that they described in a paper published in the journal\u00a0Biological Conservation\u00a0<\/em>in January.<\/p>\n\n\n\n

The scientists \u2013 Michael Samuel and Wei Liao, from Wisconsin, and Carter T. Atkinson and Dennis A. LaPointe from the USGS \u2013 simulated what might occur if \u2018i\u2018iwi (Drepanis coccinea<\/em>) that had been genetically engineered to resist malaria were released into wild, non-resistant populations. Although \u2018i\u2018iwi are highly sensitive to malaria, with more than 90 percent of those infected succumbing to the disease, they are still relatively abundant on the Big Island.<\/p>\n\n\n\n

The computer models assumed that one of the chief obstacles \u2013 the development of a population of \u2018i\u2018iwi that do not just tolerate malaria, but are actually able to resist infection \u2013 was an accomplished fact and that this trait would be passed on to offspring. (The authors noted that even if malaria-tolerant \u2018i\u2018iwi populations could be established, the birds would still serve as \u201can important disease reservoir for other Hawaiian species that currently exist only in high elevations with low malaria risk.\u201d)<\/p>\n\n\n\n

Simulations were run to look at the effect of the release of these resistant birds into the wild at various times and in various numbers under three climate change scenarios, as\u00a0modeled by the Intergovernmental Panel on Climate Change. \u201cWe are just working through all the options that are out there,\u201d LaPointe said as he and Atkinson discussed the article in an interview last month with\u00a0Environment Hawai\u2018i<\/em>. Both took pains to stress that they were not recommending this as an option, but rather just putting it out there for consideration.<\/p>\n\n\n\n

With all the recent advances in genetic engineering that have occurred over the last couple of years, LaPointe added, he and his co-authors were exploring what might be required if it were possible to \u201cmodify an organism to save it from the brink of extinction.<\/p>\n\n\n\n

\u201cCould we find, or could we modify, a honeycreeper so that it is actually resistant to malaria, and not just tolerant? And if we could do that, is there time to put it in the environment and actually have it propagate through the environment and rescue the birds from an otherwise certain path to extinction?\u201d<\/p>\n\n\n\n

The article, \u201cFacilitated adaptation for conservation \u2013 Can gene editing save Hawai\u2018i\u2019s endangered birds from climate driven avian malaria?\u201d \u2013 concludes that this \u201cmay be a useful alternative or additional strategy if control of malaria transmission by mosquitoes is not suc- cessful or proves too costly.\u201d<\/p>\n\n\n\n

As recently as 2017, the same four authors \u2013 Liao, Atkinson, LaPointe, and Samuel \u2013 suggested that mosquito control strategies could be the best way to ward against malaria transmission at high elevations and, combined with other approaches, help protect native birds at mid-level elevations. (See their paper, \u201cMitigating Future Avian Malaria Threats to Hawaiian Forest Birds from Climate Change,\u201d PLOS\/One<\/em>, January 6, 2017.)<\/p>\n\n\n\n

To date, however, research into mosquito control on a landscape scale \u2013 the scale needed to meaningfully address the threat of avian malaria \u2013 has not borne fruit. Since 2016, the state has supported efforts to infect\u00a0Culex quinquefasciatus\u00a0<\/em>mosquitoes, which carry the malaria parasite to birds, with a variety of Wolbachia bacteria that will make the males infertile with wild female mosquitoes and\u00a0suppress wild populations if sufficient\u00a0numbers of males are released. A related approach with Aedes mosquitoes is being used in other parts of the world, but with these mosquitoes, infection with a new strain of Wolbachia can actually prevent the mosquitoes and their offspring from transmitting human pathogens such as the Dengue virus. Whether something similar could occur with Culex and avian malaria is still unknown. Despite\u00a0additional funding in 2017 and 2018\u00a0from both state and federal agencies, \u201cthe project still did not result in the development of a Wolbachia infected\u00a0C. quinquefasciatus\u00a0<\/em>mosquito, due to the complexity of methodologies and technical specialization required for such an undertaking,\u201d according to a report on the project submitted to the Legislature by the state Department of Agriculture in December.<\/p>\n\n\n\n

But in any case, if genetically modified\u00a0\u2018i\u2018iwi resistant to malaria are able to be\u00a0developed and then released in sufficient\u00a0numbers to mate with wild birds, mosquito control would actually work against the goal of developing a malaria resistance in the wild population.<\/p>\n\n\n\n

Absent the malaria-carrying mosquitoes, the resistant \u2018i\u2018iwi would have no evolutionary advantage. That is, non-resistant birds are just as likely to survive and reproduce as the resistant ones. To ensure that the genetic ability to resist malaria becomes dominant over time,\u00a0sufficient selection pressure favoring resistance \u2013 in the form of disease \u2013 needs to be present. No mosquitoes means no such pressure.<\/p>\n\n\n\n

For now, though, said LaPointe, \u201cthe focus is on mosquito control with existing\u00a0technology… In 20 years, if we find that\u00a0that doesn\u2019t work, and the technology exists for developing a resistant \u2018i\u2018iwi and it\u2019s acceptable to the public, then is this\u201d \u2013 release of malaria-resistant \u2018i\u2018iwi \u2013 \u201can option, at that time?\u201d <\/p>\n\n\n\n

Under the scenarios described in the\u00a0Conservation Biology\u00a0<\/em>article, however, the sooner the release of resistant birds occurs at mid-elevation forests, the better. \u201cWhen releases of resistant \u2018i\u2018iwi were 3 birds per square kilometer (1,311 total birds during 1-2 years) between 2030 and 2050,\u201d the authors write, \u201cwe predicted\u00a0high population levels (more than 800\u00a0\u2018i\u2018iwi per square kilometer) of malaria-resistant \u2018i\u2018iwi could be established by 2100\u201d under the most dire climate model (RCP8.5).
<\/p>\n\n\n\n

\u201cOverall earlier release of more resistant birds in mid-elevation forests meant that \u2018i\u2018iwi populations recovered sooner and achieved higher population levels.\u00a0Resistant \u2018i\u2018iwi dominated the total \u2018i\u2018iwi\u00a0population within 20 to 30 years after release and were more abundant than the predicted \u2018i\u2018iwi density without the release of resistant birds,\u201d they found.<\/p>\n\n\n\n

Another option considered in the paper was that of releasing resistant \u2018i\u2018iwi on islands such as O\u2018ahu, where the natural populations have been severely reduced\u00a0or have died out altogether. \u201cYou could\u00a0establish a population on an island where there are currently no birds, so you could generate enough birds in the wild, and then be able to draw birds from that island when you\u2019re ready to release them on the other islands,\u201d Atkinson said.<\/p>\n\n\n\n

The authors simulated population growth of resistant \u2018i\u2018iwi after the release of 30, 40, or 50 birds in an area where \u2018i\u2018iwi are no longer found: \u201cOur results showed that populations of more than 2,000 malaria-resistant \u2018i\u2018iwi could be achieved within 30 years of introduction from the release of 30 birds and somewhat sooner for initial releases of 40 or 50 birds.\u201d<\/p>\n\n\n\n

The development of a resistant \u2018i\u2018iwi is still a moon shot, they both admitted. When he was approached about the idea,\u00a0Atkinson said, \u201cI was kind of incredulous\u00a0about the whole idea of genetically engi- neering a bird that is resistant to malaria.\u00a0It will be extremely difficult to do. The\u00a0immune response to malaria is so complicated. We don\u2019t really understand exactly how it works even in human malaria. To think you can modify maybe one gene to make a bird resistant or refractory is being really optimistic.\u201d
Even if all the technical obstacles can be overcome, there remains the matter of possible cultural resistance. \u201cThe application of gene editing to conserve wildlife populations is a controversial issue,\u201d the authors observe, although in the case of last-ditch efforts to save high-value endangered species, public acceptability\u00a0is \u201csignificantly higher.\u201d<\/p>\n\n\n\n

\u201cIn traditional Hawaiian culture, native plants and animals are often viewed as the manifestation of gods or ancestral spirits,\u201d they note. \u201cProposed genetic\u00a0modification of the Hawaiian staple\u00a0crop, taro, met with such resistance from Hawaiian cultural practitioners that a statewide ban was enacted in\u00a02009. \u2018I\u2018iwi and many other native forest\u00a0birds may be \u2018aumakua, family gods, or spiritual guardians and as such would be considered sacred. Consideration of the traditional beliefs of Hawaiians would be\u00a0an important first step before any genetic modification of \u2018i\u2018iwi is attempted.\u201d Even assuming that cultural considerations are satisfactorily addressed, how likely is it that the technical competence to develop a malaria-resistant \u2018i\u2018iwi will be\u00a0achieved and a sufficiently large captive\u00a0population will be developed and released in time to save the species?
<\/p>\n\n\n\n

\u201cI tend to be pessimistic about that, that it\u2019s going to be anytime soon. I don\u2019t think I\u2019ll be around to see it if it\u00a0happens,\u201d LaPointe said. \u201cBut the pace of these things is unpredictable in my mind. All it takes is identifying the right gene and somebody who wants to invest in the effort.\u201d<\/p>\n\n\n\n

\u201cMalaria is a really difficult problem\u00a0to solve,\u201d Atkinson added. \u201cPeople have been trying to develop a malaria vaccine for over 50 years and we still don\u2019t have anything that is completely effective. The parasite is well adapted to evading the immune system.\u201d<\/p>\n\n\n\n

\u2014Patricia Tummons<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

Temperatures are rising. And as they soar, so, too, do the mosquitoes that carry the parasite that causes avian malaria, fatal to so many of the native Hawaiian forest birds. For years, scientists and biologists concerned with the health of … Continued<\/a><\/p>\n","protected":false},"author":1,"featured_media":12253,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11,466],"tags":[7],"class_list":["post-12252","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-climate-change","category-march-2020","tag-patricia-tummons"],"_links":{"self":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/12252","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=12252"}],"version-history":[{"count":0,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/12252\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/media\/12253"}],"wp:attachment":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=12252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}