The two homosequential species Chironomus riparius Mg. and Chironomus piger Strenzke are differentiated at cytological level by the localization of their constitutive heterochromatin. They can also be distinguished by number and position of sites of two tandem repeated DNA families (Alu and Hinf) as well as by number and position of fixed insertion sites of the retrotransposon NLRCth1. The phylogenetically youngest species C.riparius is much more rich in the above mentioned repetitive DNA clusters than the phylogenetically oldest species C.piger. It is possible that both species diverged from a common ancestor because of amplification and transposition processes of repetitive DNA elements in the youngest species. In both species localization of repetitive DNA and breakpoints of chromosome rearrangements were significantly more frequent in proximal than in distal regions of chromosomes. C.riparius has a high frequency of somatic rearrangements (51.92%) distributed in the whole genome while C. piger has a far lower amount of somatic aberrations (21.31%) concentrated in centromere or pericentromere regions of chromosomes. We show that the comparatively larger amount of heterochromatin within the C. riparius genome correlates with a propensity towards chromosomal rearrangements higher than that observed in C. piger .

Repetitive DNA localization in two homosequential species of the genus Chironomus Kieffer (Diptera chironomidae) and their genome reaction to the quality of sediments

SELLA, Gabriella;
2008-01-01

Abstract

The two homosequential species Chironomus riparius Mg. and Chironomus piger Strenzke are differentiated at cytological level by the localization of their constitutive heterochromatin. They can also be distinguished by number and position of sites of two tandem repeated DNA families (Alu and Hinf) as well as by number and position of fixed insertion sites of the retrotransposon NLRCth1. The phylogenetically youngest species C.riparius is much more rich in the above mentioned repetitive DNA clusters than the phylogenetically oldest species C.piger. It is possible that both species diverged from a common ancestor because of amplification and transposition processes of repetitive DNA elements in the youngest species. In both species localization of repetitive DNA and breakpoints of chromosome rearrangements were significantly more frequent in proximal than in distal regions of chromosomes. C.riparius has a high frequency of somatic rearrangements (51.92%) distributed in the whole genome while C. piger has a far lower amount of somatic aberrations (21.31%) concentrated in centromere or pericentromere regions of chromosomes. We show that the comparatively larger amount of heterochromatin within the C. riparius genome correlates with a propensity towards chromosomal rearrangements higher than that observed in C. piger .
2008
10
41
48
Michailova P; Petrova N; Sella G; Ilkova J.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/132872
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