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Development, genetic and cytogenetic analyses of genetic sexing strains of the Mexican fruit fly, Anastrepha ludens Loew (Diptera: Tephritidae).

Zepeda-Cisneros CS, Meza Hernández JS, García-Martínez V, Ibañez-Palacios J, Zacharopoulou A, Franz G - BMC Genet. (2014)

Bottom Line: To increase the efficiency of this technique, we have developed a genetic sexing strain (GSS) in which the sexing mechanism is based on a pupal colour dimorphism (brown-black) and is the result of a reciprocal translocation between the Y chromosome and the autosome bearing the black pupae (bp) locus.The translocation strain named Tapachula-7 showed minimal effect on survival and the best genetic stability of all ten strains.The present work is the first report of the construction of GSS of Anastrepha ludens, with potential use in a future Moscafrut operational program.

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ABSTRACT

Background: Anastrepha ludens is among the pests that have a major impact on México's economy because it attacks fruits as citrus and mangoes. The Mexican Federal government uses integrated pest management to control A. ludens through the Programa Nacional Moscas de la Fruta [National Fruit Fly Program, SAGARPA-SENASICA]. One of the main components of this program is the sterile insect technique (SIT), which is used to control field populations of the pest by releasing sterile flies.

Results: To increase the efficiency of this technique, we have developed a genetic sexing strain (GSS) in which the sexing mechanism is based on a pupal colour dimorphism (brown-black) and is the result of a reciprocal translocation between the Y chromosome and the autosome bearing the black pupae (bp) locus. Ten strains producing wild-type (brown pupae) males and mutant (black pupae) females were isolated. Subsequent evaluations for several generations were performed in most of these strains. The translocation strain named Tapachula-7 showed minimal effect on survival and the best genetic stability of all ten strains. Genetic and cytogenetic analyses were performed using mitotic and polytene chromosomes and we succeeded to characterize the chromosomal structure of this reciprocal translocation and map the autosome breakpoint, despite the fact that the Y chromosome is not visible in polytene nuclei following standard staining.

Conclusions: We show that mitotic and polytene chromosomes can be used in cytogenetic analyses towards the development of genetic control methods in this pest species. The present work is the first report of the construction of GSS of Anastrepha ludens, with potential use in a future Moscafrut operational program.

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a) Anastrepha ludens mitotic metaphase chromosomes from brain ganglia of third instar male larva of the wild-type strain. b-c) Mitotic metaphases of the GSS Tapachula-7. d) Graphic representation of the Y-autosome translocation observed in the Tapachula-7 strain and its comparison with the wild-type. e-f) Mitotic metaphases of the second GSS, Tapachula -1. X, Y: represent the sex chromosomes, 2: represents the intact free autosome, Y-2: represents the translocation fragment with the Y centromere, 2-Y: represents the reciprocal translocation fragment carrying the autosomal centromere. Centromeres are indicated by circles in 2d. Bar = 10µm
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Figure 2: a) Anastrepha ludens mitotic metaphase chromosomes from brain ganglia of third instar male larva of the wild-type strain. b-c) Mitotic metaphases of the GSS Tapachula-7. d) Graphic representation of the Y-autosome translocation observed in the Tapachula-7 strain and its comparison with the wild-type. e-f) Mitotic metaphases of the second GSS, Tapachula -1. X, Y: represent the sex chromosomes, 2: represents the intact free autosome, Y-2: represents the translocation fragment with the Y centromere, 2-Y: represents the reciprocal translocation fragment carrying the autosomal centromere. Centromeres are indicated by circles in 2d. Bar = 10µm

Mentions: Mitotic chromosomes. Anastrepha ludens has six pairs of acrocentric chromosomes, five autosomes and a pair of sex chromosomes (Figure 2a) [21].The male is heterogametic (XY) [21]. The autosomes display the characteristic somatic pairing observed in Diptera and this is very useful for the identification of homologous chromosomes. The analysis of at least 80 cells from the GSS T(Y:bp+)-7 indicates that the translocation involves the largest autosome (chromosome 2) and the Y chromosome. As it is evident from Figures 2b,c a small distal part of this autosome is joined to the Y chromosome, while a tiny part of the Y chromosome is connected to the autosomal breakpoint. The resulting 2-Y translocation chromosome is slightly shorter (10.58 ± 0.99%) than the wild-type chromosome 2 (11.93 ± 0.8%). The reciprocal Y-2 translocation fragment in the strain T(Y:bp+)-7 is longer than the wild-type Y chromosome (2.75 ± 0.37% versus 1.71 ± 0.3%). A graphic representation of the Y-autosome translocation is shown in Figure 2d.


Development, genetic and cytogenetic analyses of genetic sexing strains of the Mexican fruit fly, Anastrepha ludens Loew (Diptera: Tephritidae).

Zepeda-Cisneros CS, Meza Hernández JS, García-Martínez V, Ibañez-Palacios J, Zacharopoulou A, Franz G - BMC Genet. (2014)

a) Anastrepha ludens mitotic metaphase chromosomes from brain ganglia of third instar male larva of the wild-type strain. b-c) Mitotic metaphases of the GSS Tapachula-7. d) Graphic representation of the Y-autosome translocation observed in the Tapachula-7 strain and its comparison with the wild-type. e-f) Mitotic metaphases of the second GSS, Tapachula -1. X, Y: represent the sex chromosomes, 2: represents the intact free autosome, Y-2: represents the translocation fragment with the Y centromere, 2-Y: represents the reciprocal translocation fragment carrying the autosomal centromere. Centromeres are indicated by circles in 2d. Bar = 10µm
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4255765&req=5

Figure 2: a) Anastrepha ludens mitotic metaphase chromosomes from brain ganglia of third instar male larva of the wild-type strain. b-c) Mitotic metaphases of the GSS Tapachula-7. d) Graphic representation of the Y-autosome translocation observed in the Tapachula-7 strain and its comparison with the wild-type. e-f) Mitotic metaphases of the second GSS, Tapachula -1. X, Y: represent the sex chromosomes, 2: represents the intact free autosome, Y-2: represents the translocation fragment with the Y centromere, 2-Y: represents the reciprocal translocation fragment carrying the autosomal centromere. Centromeres are indicated by circles in 2d. Bar = 10µm
Mentions: Mitotic chromosomes. Anastrepha ludens has six pairs of acrocentric chromosomes, five autosomes and a pair of sex chromosomes (Figure 2a) [21].The male is heterogametic (XY) [21]. The autosomes display the characteristic somatic pairing observed in Diptera and this is very useful for the identification of homologous chromosomes. The analysis of at least 80 cells from the GSS T(Y:bp+)-7 indicates that the translocation involves the largest autosome (chromosome 2) and the Y chromosome. As it is evident from Figures 2b,c a small distal part of this autosome is joined to the Y chromosome, while a tiny part of the Y chromosome is connected to the autosomal breakpoint. The resulting 2-Y translocation chromosome is slightly shorter (10.58 ± 0.99%) than the wild-type chromosome 2 (11.93 ± 0.8%). The reciprocal Y-2 translocation fragment in the strain T(Y:bp+)-7 is longer than the wild-type Y chromosome (2.75 ± 0.37% versus 1.71 ± 0.3%). A graphic representation of the Y-autosome translocation is shown in Figure 2d.

Bottom Line: To increase the efficiency of this technique, we have developed a genetic sexing strain (GSS) in which the sexing mechanism is based on a pupal colour dimorphism (brown-black) and is the result of a reciprocal translocation between the Y chromosome and the autosome bearing the black pupae (bp) locus.The translocation strain named Tapachula-7 showed minimal effect on survival and the best genetic stability of all ten strains.The present work is the first report of the construction of GSS of Anastrepha ludens, with potential use in a future Moscafrut operational program.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Anastrepha ludens is among the pests that have a major impact on México's economy because it attacks fruits as citrus and mangoes. The Mexican Federal government uses integrated pest management to control A. ludens through the Programa Nacional Moscas de la Fruta [National Fruit Fly Program, SAGARPA-SENASICA]. One of the main components of this program is the sterile insect technique (SIT), which is used to control field populations of the pest by releasing sterile flies.

Results: To increase the efficiency of this technique, we have developed a genetic sexing strain (GSS) in which the sexing mechanism is based on a pupal colour dimorphism (brown-black) and is the result of a reciprocal translocation between the Y chromosome and the autosome bearing the black pupae (bp) locus. Ten strains producing wild-type (brown pupae) males and mutant (black pupae) females were isolated. Subsequent evaluations for several generations were performed in most of these strains. The translocation strain named Tapachula-7 showed minimal effect on survival and the best genetic stability of all ten strains. Genetic and cytogenetic analyses were performed using mitotic and polytene chromosomes and we succeeded to characterize the chromosomal structure of this reciprocal translocation and map the autosome breakpoint, despite the fact that the Y chromosome is not visible in polytene nuclei following standard staining.

Conclusions: We show that mitotic and polytene chromosomes can be used in cytogenetic analyses towards the development of genetic control methods in this pest species. The present work is the first report of the construction of GSS of Anastrepha ludens, with potential use in a future Moscafrut operational program.

Show MeSH
Related in: MedlinePlus