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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.

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.

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Mitotic karyotypes of members of the B. dorsalis species complex. a and d) B. dorsalis s.s. (Saraburi), b) B. papayae, c) B. invadens, e) B. carambolae, f) B. philippinensis. a-c) females, d-f) males. Scale bar represents 5 μm.
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Figure 1: Mitotic karyotypes of members of the B. dorsalis species complex. a and d) B. dorsalis s.s. (Saraburi), b) B. papayae, c) B. invadens, e) B. carambolae, f) B. philippinensis. a-c) females, d-f) males. Scale bar represents 5 μm.

Mentions: All the members of the complex analyzed here (B. dorsalis s.s., B. philippinensis, B. papayae, B. invadens and B. carambolae) show five pairs of autosomes and one pair of heteromorphic sex chromosomes (XX/XY). The autosomes have been numbered II to VI according to descending size order [50]. The two longest (II and III) and the two shortest (V and VI) autosomes can be described as submetacentric, although with different arm ratios, and one autosome (IV) can be described as metacentric. The sex chromosomes are the smallest of the set, with the × being elongated, metacentric, with one of the arms being darker stained than the other and the Y being dot-like (Figure 1). The observed karyotype is referred as form A [61]. No differences in the karyotypes were observed.


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)

Mitotic karyotypes of members of the B. dorsalis species complex. a and d) B. dorsalis s.s. (Saraburi), b) B. papayae, c) B. invadens, e) B. carambolae, f) B. philippinensis. a-c) females, d-f) males. Scale bar represents 5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Mitotic karyotypes of members of the B. dorsalis species complex. a and d) B. dorsalis s.s. (Saraburi), b) B. papayae, c) B. invadens, e) B. carambolae, f) B. philippinensis. a-c) females, d-f) males. Scale bar represents 5 μm.
Mentions: All the members of the complex analyzed here (B. dorsalis s.s., B. philippinensis, B. papayae, B. invadens and B. carambolae) show five pairs of autosomes and one pair of heteromorphic sex chromosomes (XX/XY). The autosomes have been numbered II to VI according to descending size order [50]. The two longest (II and III) and the two shortest (V and VI) autosomes can be described as submetacentric, although with different arm ratios, and one autosome (IV) can be described as metacentric. The sex chromosomes are the smallest of the set, with the × being elongated, metacentric, with one of the arms being darker stained than the other and the Y being dot-like (Figure 1). The observed karyotype is referred as form A [61]. No differences in the karyotypes were observed.

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