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Karyotypical characteristics of two allopatric African populations of anhydrobiotic Polypedilum Kieffer, 1912 (Diptera, Chironomidae) originating from Nigeria and Malawi.

Petrova NA, Cornette R, Shimura S, Gusev OA, Pemba D, Kikawada T, Zhirov SV, Okuda T - Comp Cytogenet (2015)

Bottom Line: The African chironomid Polypedilumvanderplanki Hinton, 1951 is the only chironomid able to withstand almost complete desiccation in an ametabolic state known as anhydrobiosis.Both populations, Nigerian and Malawian, showed the same number of chromosomes (2n=8), but important differences were found in the band sequences of polytene chromosomes, and in the number and the arrangement of active regions between the two populations.Such important differences raise the possibility that the Malawian population could constitute a distinct new species of anhydrobiotic chironomid.

View Article: PubMed Central - PubMed

Affiliation: Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia.

ABSTRACT
The African chironomid Polypedilumvanderplanki Hinton, 1951 is the only chironomid able to withstand almost complete desiccation in an ametabolic state known as anhydrobiosis. The karyotypes of two allopatric populations of this anhydrobiotic chironomid, one from Nigeria and another from Malawi, were described according to the polytene giant chromosomes. The karyotype from the Nigerian population was presented as the reference chromosome map for Polypedilumvanderplanki. Both populations, Nigerian and Malawian, showed the same number of chromosomes (2n=8), but important differences were found in the band sequences of polytene chromosomes, and in the number and the arrangement of active regions between the two populations. Such important differences raise the possibility that the Malawian population could constitute a distinct new species of anhydrobiotic chironomid.

No MeSH data available.


Related in: MedlinePlus

Different patterns of polymorphism for the chromosomes I and II in the Malawian population. a and b chromosome I. c and d chromosome II. Chromosome arms are labeled A–B and C–D. Arrows: putative centromeres, np: regions of non-pairing, tor: heterochromatic knots due to chromosome torsion.
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Figure 6: Different patterns of polymorphism for the chromosomes I and II in the Malawian population. a and b chromosome I. c and d chromosome II. Chromosome arms are labeled A–B and C–D. Arrows: putative centromeres, np: regions of non-pairing, tor: heterochromatic knots due to chromosome torsion.

Mentions: Chromosomal polymorphism: For the majority of the studied individuals, we observed mispairing of the homologues. Uncoupled chromosome portions, as a result of torsion, were forming various structures. For example in the AB chromosome (Fig. 6a, b), homologous sections near the centromere were often situated nearby each other, due to asynapsis, and thus the area near the centromere appeared as a thickening.


Karyotypical characteristics of two allopatric African populations of anhydrobiotic Polypedilum Kieffer, 1912 (Diptera, Chironomidae) originating from Nigeria and Malawi.

Petrova NA, Cornette R, Shimura S, Gusev OA, Pemba D, Kikawada T, Zhirov SV, Okuda T - Comp Cytogenet (2015)

Different patterns of polymorphism for the chromosomes I and II in the Malawian population. a and b chromosome I. c and d chromosome II. Chromosome arms are labeled A–B and C–D. Arrows: putative centromeres, np: regions of non-pairing, tor: heterochromatic knots due to chromosome torsion.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488965&req=5

Figure 6: Different patterns of polymorphism for the chromosomes I and II in the Malawian population. a and b chromosome I. c and d chromosome II. Chromosome arms are labeled A–B and C–D. Arrows: putative centromeres, np: regions of non-pairing, tor: heterochromatic knots due to chromosome torsion.
Mentions: Chromosomal polymorphism: For the majority of the studied individuals, we observed mispairing of the homologues. Uncoupled chromosome portions, as a result of torsion, were forming various structures. For example in the AB chromosome (Fig. 6a, b), homologous sections near the centromere were often situated nearby each other, due to asynapsis, and thus the area near the centromere appeared as a thickening.

Bottom Line: The African chironomid Polypedilumvanderplanki Hinton, 1951 is the only chironomid able to withstand almost complete desiccation in an ametabolic state known as anhydrobiosis.Both populations, Nigerian and Malawian, showed the same number of chromosomes (2n=8), but important differences were found in the band sequences of polytene chromosomes, and in the number and the arrangement of active regions between the two populations.Such important differences raise the possibility that the Malawian population could constitute a distinct new species of anhydrobiotic chironomid.

View Article: PubMed Central - PubMed

Affiliation: Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia.

ABSTRACT
The African chironomid Polypedilumvanderplanki Hinton, 1951 is the only chironomid able to withstand almost complete desiccation in an ametabolic state known as anhydrobiosis. The karyotypes of two allopatric populations of this anhydrobiotic chironomid, one from Nigeria and another from Malawi, were described according to the polytene giant chromosomes. The karyotype from the Nigerian population was presented as the reference chromosome map for Polypedilumvanderplanki. Both populations, Nigerian and Malawian, showed the same number of chromosomes (2n=8), but important differences were found in the band sequences of polytene chromosomes, and in the number and the arrangement of active regions between the two populations. Such important differences raise the possibility that the Malawian population could constitute a distinct new species of anhydrobiotic chironomid.

No MeSH data available.


Related in: MedlinePlus