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

 

Amnesty: Campaign Mass Hangings And Extermination At Syrian Prison

A chilling new report by Amnesty International exposes the Syrian government’s calculated campaign of extrajudicial executions by mass hangings at Saydnaya Prison. Between 2011 and 2015, every week and often twice a week, groups of up to 50 people ... More>>

Russian Hack Job?: White House - Actions In Response To Russian Malicious Cyber Activity & Harassment

President Obama authorized a number of actions in response to the Russian government’s aggressive harassment of U.S. officials and cyber operations aimed at the U.S. election in 2016. More>>


Israel/Palestine: Michael Field - Background To How Israel Nearly Went To War With New Zealand

New Zealand and Senegal managed to get the United Nations Security Council to pass resolution 2334 which said Israel’s settlements in Palestinian territory violate international law and undermine a two-state solution in Israel's conflict with Palestine. More>>

ALSO:

US Indigenous Affairs: How President Obama Has Protected Our Sacred Land

I am very proud to be both Navajo and American. As the President of the Navajo Nation, I’ve dedicated my life to ensuring that, as a Navajo, my story -- and our stories -- are part of our collective American history. Today, I want to share one of those stories with you. More>>


Binoy Kampmark: The Berlin Truck Attack And The Refugee Question

The hard-nosed neo-cons were certainly showing little interest in linking arguments, examining evidence, or even considering elementary logic in the aftermath of the Berlin truck attack near the Gedächtniskirche. With the bodies fresh in the morgue, former US ambassador to the United Nations, John Bolton, peered into the mind of the everyday German, and found teeth chattering fear. More>>

Demonetisation: Gordon Campbell On India’s Huge Socio-Economic Experiment

Without much coverage at all in the West, India has just been engaged for the past few weeks in one of the world’s biggest socio-economic experiments since the Cultural Revolution in China. More>>

Gordon Campbell: On The Death Of Fidel Castro

New Zealand likes to think we played our part – via the 1981 Springbok tour – in bringing the apartheid regime in South Africa to an end… Jacob Zuma treated the death of Fidel Castro at the weekend as an occasion to pay a heartfelt tribute to the thousands of Cuban soldiers who travelled across the world to inflict the first significant military defeat on the forces of white supremacy. More>>

ALSO:

Get More From Scoop

 
 
 
 
World
Search Scoop  
 
 
Powered by Vodafone
NZ independent news