Genetic

GENETIC INSECT CONTROL
GROUP:
DOAN THIEN THANH BT070134
HO THI PHUONG THAO BT070132
VIETNAM NATIONAL UNIVERSITY HO CHI MINH CITY- INTERNATIONAL UNIVERSITY
BIOTECHNOLOGY DEPARTMENT
APPLIED ENTOMOLOGY
LECTURER: Dr. ANNETH R.R.
OUTLINE
What is genetic insect control?
Definition.
Purposes.
Advantages and disadvantages.
How?
Factors affect on genetic insect control.
Sterile insect technique – SIT.
Other Genetic Approaches to Insect Control.
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1. GENETIC INSECT CONTROL
Definition
Basic principle: utilize factors which will lead to reproductive failure.

“The use of any condition of treatment that can reduce the reproductive potential of noxious forms by alternating or replacing the hereditary material”. (WHO scientific group on genetics and insecticide resistance).
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Purposes
Control the growth and development of insect.
Regulation insect population.
Control pest infestation.
Protecting commercial crops.
Protect human health from harmful insects (like mosquitoes).
Production of medically proteins.
Improvement of beneficial insects.
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Advantages and disadvantages
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How?
Based on the induction of dominant lethal mutations in the sperm:
By ionizing radiations or chemical sterilants.

By physical methods.
By genetic mechanisms.
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Factors affect on genetic insect control
Natural density levels.
Cost of rearing.
Releasing the number of insects required.
Degree of annoyance or damaged causes by the released insect.
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2. STERILE INSECT TECHNIQUE
Sterile insect technique (SIT)
1950s - Dr. Raymond C. Bushland and Dr. Edward F. Knipling. (Received the 1992 World Food Prize)
Most widely - most successful.
Sterile male technique or sterile insect release method.
Against insect disease vector.
Suit for insect species that mate only once or if there is multiple mating, sperm from the first mating is the sperm that fuses with eggs.
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How?
Principle:
Sterile insects + “wild” insects  infertile eggs.
How frequently?
Twice a week up to 12 weeks
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Experiment
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SIT- significances
Produce large numbers of target insect.
Sterilize large numbers of target insect.
Competitive insect can be released after sterilization.
Tools will assess native populations accurately before and after release of the treated insects.

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Applications
Pink Bollworm (Pectinophora gossypiella Saunders)/USA (California).
Control Culex quinquefasciatus in Sea Horse Key, Florida coast.
Screwworm fly /USA, Mexico, Libya.
Mediterranean Fruit Fly (Ceratitis capitata Wiedemann)/USA (California), Mexico.
Melon Fly (Dacus cucurbitae Coquillett) / Japan, Taiwan
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Advantages/ disadvantages
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Other Genetic Approaches to Insect Control
Inherited sterility.
Cytoplasmic incompatibility.
Other genetic approaches.
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Inherited sterility
Referred to as delayed sterility, F1 sterility, partial sterility…
Suiting for insects that contain polycentric chromosomes.
Involving the transmission of aberrant chromosome from the released to the native population.
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Inherited sterility
2 ways:
Radiation therapy  break chromosomes sterility.
Culturing stocks of the target species which contains homozygous translocations (depend on number and size of the translocations carried by each individual)
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The normal chromosome complement of the pink bollworm consists of 30 distinct pairs of chromosomes.
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Chromosomal translocations in an F1 male whose father received 6 krad of gamma radiation
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Inherited sterility- advantages
enhanced reproductive competitiveness of the partially sterilized individuals compared to the fully sterilized individual used in SIT

The production have higher numbers than the primary release organism
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Cytoplasmic incompatibility
Between insects of the same species with different Wolbachia infection status.
Sterility is due to a cytoplasmic factor transmitted through the egg → kill the sperm of the incompatible male after its entry into the egg
Either unidirectional or bidirectional:
Unidirectional CI : an infected male mates with an uninfected female
Bidirectional CI : in mating between infected individual harboring different strains of Wolbachia
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Cytoplasmic incompatibility
Achieving by mass production and release of incompatile males insects to control wild population of disease vectors and of agricultural pests
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Presence of Wolbachia in transinfected C.capitata embryos, ovaries, and testes.
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Other genetic approaches
Principle:
Release not sterile insects produce sex-ratio distorters (SRDs) meiotic drive decline population.
SRDs: heritable elements > modify the sex ratio > promote transmission.
Meiotic drive: mixed genome of parents sexual offspring unable to reproduce.
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Example
Drosophila melanogaster.
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D. willistoni ♀ X D. melanogaster ♂
F1 primarily ♀
D. melanogaster ♀ X rare F1 ♂
BC1 primarily ♀

After treated with SRDs agents, in SR progenies, male embryos fail to develop due to chromosome abnormalities in early cell divisions
References
Alan C. Bartlett and. Robert T Staten USDA, ARS, Western Cotton Research Laboratory, APHIS, PPQ, Phoenix Methods Development Center Phoenix, AZ 85040. “The Sterile Insect Release Method and Other Genetic Control Strategies”. From http://ipmworld.umn.edu/chapters/bartlett.htm.
Nancy A. Rechcigl.“Biological and biotechnological control of insect pests”. Published by CRC Press, 1999.
Sex ratio- concepts and research methods. Cambridge University Press.
George Davidson. Genetic control of insect pests. Published by Academic Press, 1974. Original from the University of California
John Jaenike Department of Biology, University of Rochester, Rochester, New York 14627. SEX CHROMOSOME MEIOTIC DRIVE. Retrieved from http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.ecolsys.32.081501.113958.

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THANKS FOR YOUR ATTENTION