LINKAGE OF A GENE FOR DDT–RESISTANCE IN ADULTS OF THE MOSQUITO AEDES AEGYPTI

1975 ◽  
Vol 17 (3) ◽  
pp. 311-322 ◽  
Author(s):  
Judith M. Hitchen ◽  
R. J. Wood
Keyword(s):  
Linkage Group ◽  
Aedes Aegypti ◽  
Group Iii ◽  
Ddt Resistance

The gene RDDT2, which gives resistance to DDT in the imago of Aedes aegypti L. has been mapped on linkage group III with respect to six visible markers. The best interpretation of the order of the genes is:–blp – blt – co – fz – wi – RDDT2 – min, but the orderblp – blt – co – fz – RDDT2 – wi – min is also possible.

scholarly journals The influence of the y locus on DDT resistance in the mosquito Aedes aegypti L

1970 ◽  
Vol 16 (1) ◽  
pp. 37-47 ◽  
Author(s):  
R. J. Wood
Keyword(s):  
Linkage Group ◽  
Aedes Aegypti ◽  
Environmental Factor ◽  
Resistant Strain ◽  
Pleiotropic Effect ◽  
Susceptible Strain ◽  
Genetic Influences ◽  
Larval Diet ◽  
Ddt Resistance ◽  
Group Ii

SUMMARYThe influence of the linkage group II locus y on DDT resistance in Aedes aegypti has been studied in crosses between the Trinidad resistant strain and QS susceptible strain. The y locus influences DDT resistance in both R/R and R/+ larvae. The effect of y may be interpreted as reducing the penetrance of R (RDDT1), which is also located on linkage group II. y+ is partially dominant and incompletely penetrant in its resistance-enhancing role (although in its pleiotropic effect on larval colour it is dominant and fully penetrant). Penetrance of y+ is influenced by an environmental factor, probably associated with the larval diet.The effect of y on resistance is evaluated in relation to other genetic influences on the expression of RDDT1.The significance of polymorphism at the y locus is discussed.

scholarly journals A comparative genetical study on DDT resistance in adults and larvae of the mosquito Aedes aegypti L

1967 ◽  
Vol 10 (3) ◽  
pp. 219-228 ◽  
Author(s):  
R. J. Wood
Keyword(s):  
Linkage Group ◽  
Developmental Stages ◽  
Major Gene ◽  
Group Iii ◽  
Group I ◽  
Fourth Larval Stage ◽  
Ddt Resistance ◽  
Group Ii ◽  
The Difference ◽  
Two Stages

Inheritance of DDT resistance has been studied in crosses between the highly resistant ‘T’ strain of A. aegypti (constituted by inbreeding from the TRINIDAD DDT-resistant stock) and the ‘64’ susceptible strain.Larval DDT resistance derives from a major gene RDDT1 on linkage group II, the order being RDDT1–s–y. Linkage group III may also contribute to larval resistance. Linkage group I makes no contribution.Adult DDT resistance derives from a major gene RDDT2, 18·2 ± 2·1 units from the market blt on linkage group III. Linkage group II has no influence on adult resistance.Selection with DDT to retain only RDDT1/+ segregants in larvae of backcrosses RDDT1/+×+/+ did not increase resistance in resulting adults, confirming the difference in genetic mechanism at the two stages.The F1 progenies from reciprocal crosses between ‘T’ and ‘64’ differed slightly but significantly in larval resistance, modifying the influence of the major gene RDDT1 in the heterozygote.The early developmental stages of the RDDT1/+ phenotype (up to the fourth larval stage) were more viable than the +/+ phenotype in backcross segregation. The difference in mortality probably exceeded 30%.

LINKAGE OF THE GENES FOR DDT AND DIELDRIN RESISTANCE IN LARVAE OF THE MOSQUITO AEDES AEGYPTI

1975 ◽  
Vol 17 (4) ◽  
pp. 543-551 ◽  
Author(s):  
Judith M. Hitchen ◽  
R. J. Wood
Keyword(s):  
Linkage Group ◽  
Aedes Aegypti ◽  
Resistance Gene ◽  
Ddt Resistance ◽  
Group Ii

The DDT resistance gene RDDT1, and the dieldrin resistance gene Rd1 have been mapped on linkage group II with respect to visible markers, in the mosquito Aedes aegypti L. The best interpretation of the data gives the order wa – Rd1 – ds – RDDT1 – s – y but wa – Rd1 – ds – y – s – RDDT1 is also possible, h is very loosely linked with RDDT1. The length of the linkage group has been considerably extended from previous studies.

CROSSOVER VALUES BETWEEN DIELDRIN-RESISTANCE AND DDT-RESISTANCE AND LINKAGE-GROUP-2 GENES IN AEDES AEGYPTI

1970 ◽  
Vol 12 (3) ◽  
pp. 407-414 ◽  
Author(s):  
W. L. Lockhart ◽  
W. Klassen ◽  
A. W. A. Brown
Keyword(s):  
Linkage Group ◽  
Aedes Aegypti ◽  
Resistant Strain ◽  
Susceptible Strain ◽  
Total Distance ◽  
Resistant Strains ◽  
Ddt Resistance ◽  
Group 2

Crosses and backcrosses between five dieldrin-resistant strains and the MYS susceptible strain in Aedes aegypti indicate the order of the genes to be Dl—si — s, the distance si — s being 6-7 units and the total distance Dl — s being 25-31 units.Crosses between the Trinidad DDT-resistant strain and the MYS marker strain indicate the order to be si — s — DDT, the distance si — s being 4 units and the total distance s — DDT being 10 units. Crosses between this strain and the AO and Multiple marker strains indicate the order to be y — s — DDT.These results indicate that the order of the genes in linkage-group 2 of Aedes aegypti is probably Dl — si — y —s — DDT. The total crossover distance of some 45 units thus implied between Dl and DDT is, however, at variance with previous work which found the direct crossover between these two genes to be only 4-7%.

SEX AND CROSSING OVER IN LINKAGE GROUP III OF TRIBOLIUM CASTANEUM

1977 ◽  
Vol 19 (2) ◽  
pp. 259-263 ◽  
Author(s):  
Alexander Sokoloff
Keyword(s):  
Sex Differences ◽  
Linkage Group ◽  
Tribolium Castaneum ◽  
Relative Position ◽  
Genetic Background ◽  
Crossing Over ◽  
Group Iii ◽  
The Third ◽  
Main Factors ◽  
Coleoptera Tenebrionidae

The relative position of the genes black (b), light ocular diaphragm (lod) and aureate (au) for the third linkage group of T. castaneum (Herbst) (Coleoptera, Tenebrionidae) has been determined as b – lod – au. The distances between the various genes vary, depending on the cross. The b++/+ lod au ♂ × + lod au/+ lod au ♀ crosses give the following recombination values: au – lod = 18.32 ± 1.21%; b – lod = 21.05 ± 1.51% and b – au = 37.43 ± 1.27%. The reciprocal crosses give au – lod = 27.67 ± 1.62%; b – lod = 13.97 ± 1.26% and b – au = 39.79 ± 1.78%. For the larger distances encompassed in the b – au region the recombination values in the two sexes were not significantly different. For the shorter b – lod region the recombination values were significantly larger in the females than in the males, while for the adjacent lod – au region the opposite was true. On the basis of the current literature it would appear that the main factors contributing to these sex differences in recombination are the modifiers which are different in the genetic background of the two sexes.

Dehydrochlorination and DDT-Resistance in Aedes aegypti

1963 ◽  
Vol 56 (4) ◽  
pp. 511-517 ◽  
Author(s):  
Z. H. Abedi ◽  
J. R. Duffy ◽  
A. W. A. Brown
Keyword(s):  
Aedes Aegypti ◽  
Ddt Resistance

The genetic and RFLP characterization of the left end of linkage group III in Caenorhabditis elegans

Genome ◽  
1993 ◽  
Vol 36 (4) ◽  
pp. 712-724 ◽  
Author(s):  
Dave Pilgrim
Keyword(s):  
Caenorhabditis Elegans ◽  
Linkage Group ◽  
Genetic Map ◽  
Physical Map ◽  
Group Iii ◽  
C Elegans ◽  
Genomic Regions ◽  
Caenorhabditis Elegans Genome ◽  
Selection Of

A genetic approach was taken to identify new transposable element Tc1 -dependent polymorphisms on the left end of linkage group III in the nematode Caenorhabditis elegans. The cloning of the genomic DNA surrounding the Tc1 allowed the selection of overlapping clones (from the collection being used to assemble the physical map of the C. elegans genome). A contig of approximately 600–800 kbp in the region has been identified, the genetic map of the region has been refined, and 10 new RFLPs as well as at least four previously characterized genetic loci have been positioned onto the physical map, to the resolution of a few cosmids. This analysis demonstrated the ability to combine physical and genetic mapping for the rapid analysis of large genomic regions (0.5–1 Mbp) in genetically amenable eukaryotes.Key words: Caenorhabditis elegans, genome analysis, RFLP, physical map, genetic map.

DOMINANT-AND-RECESSIVE EPISTASIS IN A HOMEOTIC MOSQUITO MUTANT

1976 ◽  
Vol 18 (4) ◽  
pp. 593-600
Author(s):  
Satish C. Bhalla
Keyword(s):  
Linkage Group ◽  
Wild Type ◽  
Pure Strain ◽  
Group Iii ◽  
Homeotic Mutant ◽  
Culex Pipiens Fatigans ◽  
Group I ◽  
Ratio Data ◽  
Independent Segregation ◽  
Selection For

Folowing selection for 15 generations a pure strain of a homeotic mutant spur was isolated from a Brazilian population of the mosquito Culex pipiens fatigans. Monohybrid crosses showed a 13:3 segregation indicating dominant-and-recessive epistasis for wild-type vs. spur. This implies that a dominant allele at one locus and a recessive at the other interact to produce the mutant phenotype. Dihybrid crosses with linkage group II markers yellow and ruby gave 39:13:9:3 ratios indicating independent segregation. However, the dihybrid cross with linkage group I marker maroon showed a highly significant departure from 39:13:9:3 ratio. Data available indicate that the phenotype spur is controlled by a dominant epistat in linkage group III and a recessive epistat (approximately 31.9 crossover units from maroon) in linkage group I.

scholarly journals A variegated position effect in Aspergillus nidulans

1970 ◽  
Vol 16 (3) ◽  
pp. 303-316 ◽  
Author(s):  
A. J. Clutterbuck
Keyword(s):  
Linkage Group ◽  
Aspergillus Nidulans ◽  
Position Effect ◽  
Attachment Site ◽  
Low Ph ◽  
Original Strain ◽  
Salt Medium ◽  
Group Viii ◽  
Distal Half ◽  
Group Iii

SUMMARYIn mutants at the ‘bristle’ locus of Aspergillus nidulans the conidiophore remains as a stiff hypha rather than developing a vesicle, sterigmata and conidia. The brlA 12 allele of this locus has a variegated phenotype, and genetic analysis has shown that this is associated with a translocation which has a breakpoint in the map interval adjacent to the bristle locus.The mutant phenotype is partially repaired on high-salt medium at low pH, and can also be repaired by suppressors, one of which has been mapped at a locus unlinked to brlA 12.The mutant provides proof that variegation is due to instability of gene expression and not to mutability since brlA 12 is genetically stable and can be propagated from either conidia or sterile conidiophores, the structures formed at the two extremes of variegation, and the resulting colonies in both cases are identical to the original strain.It has been shown by mitotic recombination that the translocation associated with the variegated mutant is a ‘simple translocation’ in which the distal half of linkage group VIII is attached to the end of linkage group III. This terminal attachment site does not appear to be damaged in any genetically detectable way.

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