Numeric and structural chromosome polymorphism in Rineloricaria lima (Siluriformes: Loricariidae): fusion points carrying 5S rDNA or telomere sequence vestiges

Numeric and structural chromosome polymorphism in Rineloricaria lima (Siluriformes:... The karyotypes and chromosome polymorphism in Rineloricaria lima have been examined using both conventional (Giemsa-staining, C-banding and silver impregnation) and fluorescence in situ hybridization with 18S rDNA, 5S rDNA and telomeric (TTAGGG)n probes protocols. A variation in chromosome number of 2n = 70–66 was detected in the analyzed populations, with the fundamental number (FN) ranging from 72 to 74. The 2n = 70 chromosomes and karyotypic formula 2st + 68a (NF = 72) was establish the start point of the current polymorphism. Based on this karyotype, seven fusioned and/or inverted chromosomes types (without vestiges of interstitial telomeric sites—ITS; with ITS and; carrying 5S rDNA fusion points) were described and eight karyotypes were established. It was hypothesized that one Rineloricaria branch, originally having a diploid number of 2n = 54 which appears the ancestral 2n for Loricariidae, diversified through centric fissions generating unstable sites at the break points. These unstable sites may have triggered Robertsonian fusions generating the currently observed polymorphism of 70–66 chromosomes. The formation of the chromosomes variants could have possibly led to the formation of different gametic combinations (balanced and unbalanced), which may have generated alterations in the FN above 72. These results demonstrate an important case that ITS and 5S rDNA were observed in fused chromosomes, implying that rDNA could serve as breakpoint for the fusion in Rinelocaria. Thus, all these mechanisms promote an increase in variability and assist in the maintenance of the observed polymorphism. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Reviews in Fish Biology and Fisheries Springer Journals

Numeric and structural chromosome polymorphism in Rineloricaria lima (Siluriformes: Loricariidae): fusion points carrying 5S rDNA or telomere sequence vestiges

Loading next page...
 
/lp/springer_journal/numeric-and-structural-chromosome-polymorphism-in-rineloricaria-lima-CWD03gXJgV
Publisher
Springer Netherlands
Copyright
Copyright © 2011 by Springer Science+Business Media B.V.
Subject
Life Sciences; Zoology; Freshwater & Marine Ecology
ISSN
0960-3166
eISSN
1573-5184
D.O.I.
10.1007/s11160-011-9250-6
Publisher site
See Article on Publisher Site

Abstract

The karyotypes and chromosome polymorphism in Rineloricaria lima have been examined using both conventional (Giemsa-staining, C-banding and silver impregnation) and fluorescence in situ hybridization with 18S rDNA, 5S rDNA and telomeric (TTAGGG)n probes protocols. A variation in chromosome number of 2n = 70–66 was detected in the analyzed populations, with the fundamental number (FN) ranging from 72 to 74. The 2n = 70 chromosomes and karyotypic formula 2st + 68a (NF = 72) was establish the start point of the current polymorphism. Based on this karyotype, seven fusioned and/or inverted chromosomes types (without vestiges of interstitial telomeric sites—ITS; with ITS and; carrying 5S rDNA fusion points) were described and eight karyotypes were established. It was hypothesized that one Rineloricaria branch, originally having a diploid number of 2n = 54 which appears the ancestral 2n for Loricariidae, diversified through centric fissions generating unstable sites at the break points. These unstable sites may have triggered Robertsonian fusions generating the currently observed polymorphism of 70–66 chromosomes. The formation of the chromosomes variants could have possibly led to the formation of different gametic combinations (balanced and unbalanced), which may have generated alterations in the FN above 72. These results demonstrate an important case that ITS and 5S rDNA were observed in fused chromosomes, implying that rDNA could serve as breakpoint for the fusion in Rinelocaria. Thus, all these mechanisms promote an increase in variability and assist in the maintenance of the observed polymorphism.

Journal

Reviews in Fish Biology and FisheriesSpringer Journals

Published: Dec 23, 2011

References

  • Karyotype diversity and fish conservation of southern field from South Brazil
    Artoni, RF; Vicari, MR; Almeida, MC; Moreira-Filho, O; Bertollo, LAC

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off