Biological control

a technology of biological control and biological apparatus, applied in the field of biological control, can solve the problems of reducing the fitness of the resultant stock with respect, reducing the size of the next generation, and unable to reliably yield a truly single-sex population

Inactive Publication Date: 2003-11-13
ISIS INNOVATION LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

0093] The method of the invention alternatively uses a sex-specific lethal system to achieve sex separation before or after release of organisms into the environment. In a prefer embodiment, the multicellular organism is an insect containing a homozygous dominant lethal system, the lethal effect of which is lethal only to females. In this embodiment males released into the natural environment will not be killed After mating with females, female offspring will contain at least one copy of the dominant system and be killed. However, male offspring, 50% of which contain the dominant system viable and may mate with further females. In this way, the dominant system may be transmitted to subsequent generations, although without further artificial introductions the system will eventually be lost from the gene pool.
0094] In the case in which a male contains a lethal genetic system with a female specific lethal effect, then males released into the environment will not be killed. However, the lethal effect of the lethal system is still manifested in the natural environment--even if this effect is limited to females.
0095] Sex-specific lethality may be achieved in a number of different ways. For example, it is possible to use a sex-specific lethal gene as part of the lethal system, whose gene product is toxic only in one sex. This approach will allow killing of a single sex even if expression of the lethal gene of gene product is not sex specific. Candidates for female sex-specific lethal genes include genes from the sex determination pathway, for example normally active only in males and toxic in females, or genes derived from sexual differentiation or gametogenesis systems.
0096] Alternatively, expression of the lethal gene or gene product may be controlled so that it is expressed or produced only in one sex (or in only one gamete or sexual org...

Problems solved by technology

Females which mate with sterile males produce no offspring, and the release of large numbers of sterile males, therefore, leads to a decrease in the size of the next generation.
In some cases it is possible to separate males and females by criteria such as pupal mass or time of eclosion, but these methods are unlikely reliably to yield a truly single-sex population.
Separation of males and females often involves the use of mutant strains, which have been mutagenised to induce a visible or otherwise selectable difference between the sexes, but such mutagenesis can reduce the fitness of the resultant stock with respect to the wild type, which is undesirable.
Frequently, the doses of chemicals or the dose of radiation required to induce sterilisation are very similar to that which is lethal for the organisms As such, sterile organisms are frequently impaired in their ability to mate.
Furthermore, both chemical and irradiation methods utilise technologies which are not specific to the target organism, with consequent potential danger to wo...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0173] Single Chromosome Crossos

[0174] In "single chromosome crosses" at 25.degree. C., ten to fifteen virgin females homozygous for the tTA construct and five to ten young males homozygous for the tRe construct were placed on food containing or lacking a tetracycline supplement. Their progeny were allowed to develop on this food.

1 Tetracycline conc. .mu.g / ml Female Total Male Total 0 0.sup.A, 0.sup.B, 0.sup.C, 0.sup.F, 0, 0, 0, 0 0 58, 47, 60, 51, 46, 60, 52, 54 428 0.1 46, 49, 50, 51, 52, 50, 41, 40 379 56, 42, 72, 41, 56, 72, 61, 34 434 1 52, 40, 60, 0, 60, 72, 50, 52 386 50, 51, 55, 3, 63, 54, 57, 56 389 5 41, 55, 49, 52, 48, 47, 40, 51 383 36, 47, 42, 55, 36, 55, 52, 52 375 Sxlpe tTa.sup.(A,B,C,F) .times. tRe Ras64B.sup.V12(B,C)

[0175] Sxl.sup.pe

[0176] Format for data: the 8 numbers are the results from crosses using independent insertions of each element (to control for position effect). Here, 4 insertions of Sxl.sup.pe-tTA (A, B, C, and F) were used and two of tRE-Ras 64B.sup....

example 2

[0192] Reporter Crosses

[0193] In "reporter crosses" at 25.degree. C., females homozygous carrying an insertion of Sxlp.sup.e tTa on their X chromosome (Sxlp.sup.e tTa.sup.(A)) were crossed to males carrying various reporter constructs. As with "single chromosome crosses", ten to fifteen virgin females homozygous for the tTA construct and five to ten young males homozygous for the tRe construct were placed on food containing or lacking a tetracycline supplement. Their progeny were allowed to develop on this food.

[0194] lacZ

[0195] Embryos were stained for IacZ using a standard histochemical method.

16 Tetracycline conc. .mu.g / ml LacZ positive Total LacZ negative Total 0 60, 85, 99, 60 304 78, 89, 85, 93 345 0.1 0, 0, 0, 0 0 176, 174, 178, 181 709 1 0, 0, 0, 0 0 188, 190, 181, 180 739 5 0, 0, 0, 0 0 156, 151, 159, 185 651 (Female) Sxlp.sup.e tTa.sup.(A) .times. tRe lacZ.sup.(III) (Male)

[0196]

17 Tetracycline conc. .mu.g / ml LacZ positive Total LacZ negative Total 0 57, 82, 97, 45 281 61, ...

example 3

[0205] Recombinant Chromesome Experiments

[0206] 40-50 young females and 20-25 young males raised at 25.degree. C. upon food with the indicated tetracycline supplement were allowed to mate, then transferred to normal (tetracycline-free) food after 3-4 days. These flies were transferred to fresh vials of normal food every day for 12 days, then moved on the 13th day. All the vials were incubated at 25.degree. C. while the progeny developed. The numbers of male and female progeny emerging as adults in each vial were recorded.

Tetracycline Concentration

[0207]

22 Sxl.sup.pe Tet. Conc. Day 1 Fe-Day 2 Day 3 Fe- Day 4 Day 5 Day 6 Day 7 .mu.g / ml Male male Male Female Male male Male Female Male Female Male Female Male Female 0.1 103 0 98 0 89 0 92 0 105 0 95 0 110 0 1 128 0 137 0 150 0 136 0 111 0 87 0 100 0 5 110 0 111 0 95 0 90 0 144 0 93 0 138 0 20 131 0 126 0 133 0 120 0 93 0 99 0 111 0 100 139 0 127 0 145 0 110 0 149 0 128 0 94 0 500 95 11 133 12 145 1 137 1 86 0 112 0 128 0 1000 140 12 133...

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Abstract

The invention relates to a non-human multicellular organism carrying a dominant lethal genetic system, the lethal effect of which is conditional, wherein the lethal effect of the lethal system occurs in the natural environment of the organism.

Description

[0001] The present invention relates to a method for controlling the population of an organism.[0002] Methods of biological control are known for insects and plants. One method currently employed for the control of insect populations is termed the "sterile insect technique" (SIT), also known as the "sterile insect release method" (SIRM). In this method, sterile males are released into the environment, wherein they compete with the wild-type (fertile) males for mates. Females which mate with sterile males produce no offspring, and the release of large numbers of sterile males, therefore, leads to a decrease in the size of the next generation. In this way the size of the wild population is controlled.[0003] SIT requires some mechanism for insect sterilisation. In addition, SIT commonly also employs separation of males from females, with the release of only one sex. This is desirable in the case of an agricultural pest, such as the medfly, where the female damages fruit, even if the fe...

Claims

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Application Information

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IPC IPC(8): A01K67/033C12N15/82
CPCA01K67/033A01K67/0333A01K67/0339A01K2227/706C12N15/8285A01K2217/05C12N15/8238C12N15/63Y02A40/146
Inventor ALPHEY, LUKETHOMAS, DEAN
Owner ISIS INNOVATION LTD
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