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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

Representative karyotype of the Polypedilumvanderplanki population from Nigeria. Chromosome numbers are indicated as I, II, III and IV. Chromosome arms are labeled A–B, C–D, E–F, and G. The expected locations of the centromeres are indicated by arrows and each section is numbered and delimited by short lines. N1, N2, (N3): nucleoli, BR: Balbiani ring, Inv: inversion.
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Figure 1: Representative karyotype of the Polypedilumvanderplanki population from Nigeria. Chromosome numbers are indicated as I, II, III and IV. Chromosome arms are labeled A–B, C–D, E–F, and G. The expected locations of the centromeres are indicated by arrows and each section is numbered and delimited by short lines. N1, N2, (N3): nucleoli, BR: Balbiani ring, Inv: inversion.

Mentions: The diploid chromosome number coincided with the modal diploid number of the genus Polypedilum: 2n=8 (Fig. 1) (Tavcar 1967, Porter and Martin 1977, Petrova et al. 1981, Kiknadze et al. 1991, Gavrikova and Belyanina 1993, Kerkis et al. 1996, Michailova 1989). Chromosomes were designated according to their respective lengths - I, II, III and IV, with the length ratio I=II>III>IV. The combination of arms in chromosomes was AB, CD, EF and G (Keyl 1960). It should be noted that these designations do not mean a homology with arms in the genus Chironomus. Chromosome I was metacentric, chromosomes II and III submetacentrics, and chromosome IV telocentric. The putative centromeres were clearly visible (specified by arrows in Figure 1) and looked like conspicuous heterochromatic bands, wider than the average width of the chromosome. The karyotype of the population is multinucleolar, with two nucleoli (N).


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)

Representative karyotype of the Polypedilumvanderplanki population from Nigeria. Chromosome numbers are indicated as I, II, III and IV. Chromosome arms are labeled A–B, C–D, E–F, and G. The expected locations of the centromeres are indicated by arrows and each section is numbered and delimited by short lines. N1, N2, (N3): nucleoli, BR: Balbiani ring, Inv: inversion.
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

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

Figure 1: Representative karyotype of the Polypedilumvanderplanki population from Nigeria. Chromosome numbers are indicated as I, II, III and IV. Chromosome arms are labeled A–B, C–D, E–F, and G. The expected locations of the centromeres are indicated by arrows and each section is numbered and delimited by short lines. N1, N2, (N3): nucleoli, BR: Balbiani ring, Inv: inversion.
Mentions: The diploid chromosome number coincided with the modal diploid number of the genus Polypedilum: 2n=8 (Fig. 1) (Tavcar 1967, Porter and Martin 1977, Petrova et al. 1981, Kiknadze et al. 1991, Gavrikova and Belyanina 1993, Kerkis et al. 1996, Michailova 1989). Chromosomes were designated according to their respective lengths - I, II, III and IV, with the length ratio I=II>III>IV. The combination of arms in chromosomes was AB, CD, EF and G (Keyl 1960). It should be noted that these designations do not mean a homology with arms in the genus Chironomus. Chromosome I was metacentric, chromosomes II and III submetacentrics, and chromosome IV telocentric. The putative centromeres were clearly visible (specified by arrows in Figure 1) and looked like conspicuous heterochromatic bands, wider than the average width of the chromosome. The karyotype of the population is multinucleolar, with two nucleoli (N).

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