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The Bactrocera dorsalis species complex: comparative cytogenetic analysis in support of Sterile Insect Technique applications.

Augustinos AA, Drosopoulou E, Gariou-Papalexiou A, Bourtzis K, Mavragani-Tsipidou P, Zacharopoulou A - BMC Genet. (2014)

Bottom Line: Therefore, the use of the available polytene chromosome maps for B. dorsalis s.s. as reference maps for all these five biological entities is proposed.Present data provide important insight in the genetic relationships among the different members of the B. dorsalis complex, and, along with other studies in the field, can facilitate SIT applications targeting this complex.Moreover, the availability of 'universal' reference polytene chromosome maps for members of the complex, along with the documented application of in situ hybridization, can facilitate ongoing and future genome projects in this complex.

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ABSTRACT

Background: The Bactrocera dorsalis species complex currently harbors approximately 90 different members. The species complex has undergone many revisions in the past decades, and there is still an ongoing debate about the species limits. The availability of a variety of tools and approaches, such as molecular-genomic and cytogenetic analyses, are expected to shed light on the rather complicated issues of species complexes and incipient speciation. The clarification of genetic relationships among the different members of this complex is a prerequisite for the rational application of sterile insect technique (SIT) approaches for population control.

Results: Colonies established in the Insect Pest Control Laboratory (IPCL) (Seibersdorf, Vienna), representing five of the main economic important members of the Bactrocera dorsalis complex were cytologically characterized. The taxa under study were B. dorsalis s.s., B. philippinensis, B. papayae, B. invadens and B. carambolae. Mitotic and polytene chromosome analyses did not reveal any chromosomal characteristics that could be used to distinguish between the investigated members of the B. dorsalis complex. Therefore, their polytene chromosomes can be regarded as homosequential with the reference maps of B. dorsalis s.s.. In situ hybridization of six genes further supported the proposed homosequentiallity of the chromosomes of these specific members of the complex.

Conclusions: The present analysis supports that the polytene chromosomes of the five taxa under study are homosequential. Therefore, the use of the available polytene chromosome maps for B. dorsalis s.s. as reference maps for all these five biological entities is proposed. Present data provide important insight in the genetic relationships among the different members of the B. dorsalis complex, and, along with other studies in the field, can facilitate SIT applications targeting this complex. Moreover, the availability of 'universal' reference polytene chromosome maps for members of the complex, along with the documented application of in situ hybridization, can facilitate ongoing and future genome projects in this complex.

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Hybridization sites of six different probes on salivary gland polytene chromosomes of the B. dorsalis complex species. a) gld in the B. dorsalis s.s. × B. invadens hybrid, b) hsp 70 in B. dorsalis s.s. × B. carambolae hybrid, c) ovo in B. dorsalis s.s. × B. carambolae hybrid, d) sxl in B. dorsalis s.s. × B. carambolae hybrid, e) scarlet in B. dorsalis s.s. and f) tra in B. dorsalis s.s. × B. carambolae hybrid. Arrows point to the hybridization signals. Note that signals in the hybrids show no differences between the two parental homologous chromosomes. Scale bar represents 10 μm.
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Figure 6: Hybridization sites of six different probes on salivary gland polytene chromosomes of the B. dorsalis complex species. a) gld in the B. dorsalis s.s. × B. invadens hybrid, b) hsp 70 in B. dorsalis s.s. × B. carambolae hybrid, c) ovo in B. dorsalis s.s. × B. carambolae hybrid, d) sxl in B. dorsalis s.s. × B. carambolae hybrid, e) scarlet in B. dorsalis s.s. and f) tra in B. dorsalis s.s. × B. carambolae hybrid. Arrows point to the hybridization signals. Note that signals in the hybrids show no differences between the two parental homologous chromosomes. Scale bar represents 10 μm.

Mentions: In situ localization of six unique genes, namely gld, hsp70, ovo, sxl, scarlet and tra (Table 1) was performed on the polytene chromosomes of the five taxa, as well as on the two hybrids. Each probe yielded a unique signal at the same chromosomal position in all entities. More specifically, gld localized in region 6 of 2L, hsp70 in region 26 of 3L, ovo in region 63 of 5L, Sxl in region 78 of 5R and scarlet and tra in regions 82 and 83 of arm 6L (Table 1, Figure 6).


The Bactrocera dorsalis species complex: comparative cytogenetic analysis in support of Sterile Insect Technique applications.

Augustinos AA, Drosopoulou E, Gariou-Papalexiou A, Bourtzis K, Mavragani-Tsipidou P, Zacharopoulou A - BMC Genet. (2014)

Hybridization sites of six different probes on salivary gland polytene chromosomes of the B. dorsalis complex species. a) gld in the B. dorsalis s.s. × B. invadens hybrid, b) hsp 70 in B. dorsalis s.s. × B. carambolae hybrid, c) ovo in B. dorsalis s.s. × B. carambolae hybrid, d) sxl in B. dorsalis s.s. × B. carambolae hybrid, e) scarlet in B. dorsalis s.s. and f) tra in B. dorsalis s.s. × B. carambolae hybrid. Arrows point to the hybridization signals. Note that signals in the hybrids show no differences between the two parental homologous chromosomes. Scale bar represents 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4255788&req=5

Figure 6: Hybridization sites of six different probes on salivary gland polytene chromosomes of the B. dorsalis complex species. a) gld in the B. dorsalis s.s. × B. invadens hybrid, b) hsp 70 in B. dorsalis s.s. × B. carambolae hybrid, c) ovo in B. dorsalis s.s. × B. carambolae hybrid, d) sxl in B. dorsalis s.s. × B. carambolae hybrid, e) scarlet in B. dorsalis s.s. and f) tra in B. dorsalis s.s. × B. carambolae hybrid. Arrows point to the hybridization signals. Note that signals in the hybrids show no differences between the two parental homologous chromosomes. Scale bar represents 10 μm.
Mentions: In situ localization of six unique genes, namely gld, hsp70, ovo, sxl, scarlet and tra (Table 1) was performed on the polytene chromosomes of the five taxa, as well as on the two hybrids. Each probe yielded a unique signal at the same chromosomal position in all entities. More specifically, gld localized in region 6 of 2L, hsp70 in region 26 of 3L, ovo in region 63 of 5L, Sxl in region 78 of 5R and scarlet and tra in regions 82 and 83 of arm 6L (Table 1, Figure 6).

Bottom Line: Therefore, the use of the available polytene chromosome maps for B. dorsalis s.s. as reference maps for all these five biological entities is proposed.Present data provide important insight in the genetic relationships among the different members of the B. dorsalis complex, and, along with other studies in the field, can facilitate SIT applications targeting this complex.Moreover, the availability of 'universal' reference polytene chromosome maps for members of the complex, along with the documented application of in situ hybridization, can facilitate ongoing and future genome projects in this complex.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: The Bactrocera dorsalis species complex currently harbors approximately 90 different members. The species complex has undergone many revisions in the past decades, and there is still an ongoing debate about the species limits. The availability of a variety of tools and approaches, such as molecular-genomic and cytogenetic analyses, are expected to shed light on the rather complicated issues of species complexes and incipient speciation. The clarification of genetic relationships among the different members of this complex is a prerequisite for the rational application of sterile insect technique (SIT) approaches for population control.

Results: Colonies established in the Insect Pest Control Laboratory (IPCL) (Seibersdorf, Vienna), representing five of the main economic important members of the Bactrocera dorsalis complex were cytologically characterized. The taxa under study were B. dorsalis s.s., B. philippinensis, B. papayae, B. invadens and B. carambolae. Mitotic and polytene chromosome analyses did not reveal any chromosomal characteristics that could be used to distinguish between the investigated members of the B. dorsalis complex. Therefore, their polytene chromosomes can be regarded as homosequential with the reference maps of B. dorsalis s.s.. In situ hybridization of six genes further supported the proposed homosequentiallity of the chromosomes of these specific members of the complex.

Conclusions: The present analysis supports that the polytene chromosomes of the five taxa under study are homosequential. Therefore, the use of the available polytene chromosome maps for B. dorsalis s.s. as reference maps for all these five biological entities is proposed. Present data provide important insight in the genetic relationships among the different members of the B. dorsalis complex, and, along with other studies in the field, can facilitate SIT applications targeting this complex. Moreover, the availability of 'universal' reference polytene chromosome maps for members of the complex, along with the documented application of in situ hybridization, can facilitate ongoing and future genome projects in this complex.

Show MeSH
Related in: MedlinePlus