World Video | Defence | Foreign Affairs | Natural Events | Trade | NZ in World News | NZ National News Video | NZ Regional News | Search

 


New Genetic Control Mechanism for Major Livestock Pest

June 19,

Researchers Develop Genetic Control Mechanism for Major Livestock Pest

Researchers from North Carolina State University have developed a technique to control populations of the Australian sheep blowfly – a major livestock pest in Australia and New Zealand – by making female flies dependent upon a common antibiotic to survive.

Dr. Max Scott, professor of entomology at NC State, and his research team genetically modified lines of female Australian sheep blowflies (Lucilia cuprina) so that they required doses of tetracycline in order to live. Female blowflies that did not receive the antibiotic died in the late larval or pupal stages, before reaching adulthood. Several genetically modified lines lacking tetracycline showed 100 percent female deaths.

Scott says that the gene construct responsible for lethality in antibiotic-free diets is female-specific. Interestingly and unexpectedly, the genetically modified female larvae containing the tetracycline lethality genes also took on a crimson color due to overexpression of the linked red fluorescent protein “marker gene.” This allows scientists to tell which larvae will be females and which will be males.

“Overexpression of the gene responsible for the reliance on tetracycline also seems to overexpress this marker gene,” Scott says.

Since the females will die when not provided tetracycline in their diets, the males can be separated out in the larval stage. This is essential for a “male-only” genetic control program to reduce blowfly populations, Scott says, as fertile males would pass the lethality construct on to female offspring, which would die in the absence of tetracycline. Male larval offspring, however, would still be dangerous to livestock.

In the study, the researchers showed that the tetracycline gene construct also works in Drosophila, the fruit fly “lab rat” of the insect world that is a distant cousin of the sheep blowfly. This holds promise that the genetic system will function in the New World and Old World screwworm, two major livestock pests that are close relatives of the sheep blowfly. Scott is working with the U.S. Department of Agriculture to make “male-only” strains of the New World screwworm (Cochliomyia hominivorax).

“The New World screwworm is a devastating pest of livestock that was eradicated from North and Central America by releasing sterilized male and female flies,” Scott says. However, a male-only strain offers several advantages, including potentially more efficient population suppression for the ongoing program. “Efficient genetic control systems have the potential to help eradicate some of the biggest problem pests across the globe,” he said.

The research is funded by the U.S. Department of Agriculture, National Institute of Food and Agriculture and NC State.

- kulikowski –

“Transgenic sexing system for genetic control of the Australian sheep blow fly Lucilia cuprina”

Authors: Fang Li, Holly Wantuch, Rebecca Linger, Esther Belikoff and Max Scott, North Carolina State University
Published: June 2014 online in Insect Biochemistry and Molecular Biology
DOI: 10.1016/j.ibmb.2014.06.001

Abstract: The New World screwworm and the Australian sheep blow fly Lucilia cuprina are devastating pests of livestock. The larvae of these species feed on the tissue of the living animal and can cause death if untreated. The sterile insect technique or SIT was used to eradicate screwworm from North and Central America. This inspired efforts to develop strains containing complex chromosomal rearrangements for genetic control of L. cuprina in Australia. Although one field trial was promising, the approach was abandoned due to costs and difficulties in mass rearing the strain. As the efficiency of SIT can be significantly increased if only sterile males are released, we have developed transgenic strains of L. cuprina that carry a dominant tetracycline repressible female lethal genetic system. Lethality is due to overexpression of an auto-regulated tetracycline repressible transactivator (tTA) gene and occurs mostly at the pupal stage. Dominant female lethality was achieved by replacing the Drosophila hsp70 core promoter with a Lucilia hsp70 core promoter-5/UTR for tTA overexpression. The strains carry a dominant strongly expressed marker that will facilitate identification in the field. Interestingly, the sexes could be reliably sorted by fluorescence or color from the early first instar larval stage as females that overexpress tTA also overexpress the linked marker gene. Male-only strains of L. cuprina developed in this study could form the basis for a future genetic control program. Moreover, the system developed for L. cuprina should be readily transferrable to other major calliphorid livestock pests including the New and Old World screwworm.

ENDS


© Scoop Media

 
 
 
 
 
World Headlines

 

Pakistan School Killings

GENEVA (16 December 2014) – The UN High Commissioner for Human Rights Zeid Ra’ad Al Hussein on Tuesday condemned what he described as “an utterly despicable and incomprehensibly vicious attack on defenceless children” at a co-educational school ... More>>


Sobering Data On American's Apathy About CIA Torture

Despite a scathing report on torture, a majority of survey respondents approve of the CIA's grisly methods. More>>

Sea Shepherd Intercepts Toothfish Poachers

Yesterday, at approximately 2152 AEDT, the Sea Shepherd conservation ship, Bob Barker, intercepted the illegal fishing vessel Thunder, at 62 15’ South, 81 24’ East, inside the CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources) ... More>>


Briefing On Changes In U.S. Policy Toward Cuba

Special Briefing Roberta S. Jacobson Assistant Secretary, Bureau of Western Hemisphere Affairs Press Briefing Room Washington, DC December 18, 2014More>>

ALSO:

The White House: Charting A New Course On Cuba

We are separated by 90 miles of water, but brought together through the relationships between the two million Cubans and Americans of Cuban descent that live in the United States, and the 11 million Cubans who share similar hopes for a more positive future for Cuba. More>>

ALSO:


Journalist Most Recent Victim Of Israeli Military

Bashar, a journalist from Palestine TV, was shot in the left leg at Kufr Qaddum on Friday the 5th of December 2014. More>>

ALSO:

  • Palestinian Centre For Human Rights - Swiss government’s bid to convene a summit on Palestine
  • UN News - UN-backed reconstruction efforts continue in Gaza
  • UNICEF Mobilizes To Reach People Affected By Typhoon

    As Typhoon Hagupit wreaks havoc through the Philippines, UNICEF is acting quickly to support the Filipino government’s response to the emergency, providing lifesaving supplies and services for children and women in the areas hardest hit by cyclone-force ... More>>

    ALSO:

  • FAO - FAO praises government for early typhoon warnings
  • Get More From Scoop

     
     
     
     
     
    World
    Search Scoop  
     
     
    Powered by Vodafone
    NZ independent news