An efficient Oligo‐FISH painting system for revealing chromosome rearrangements and polyploidization in Triticeae

Proechimys species are remarkable for their extensive chromosome rearrangements, representing a good model to understand genome evolution. Herein, we cytogenetically analyzed 3 different cytotypes of Proechimys gr. goeldii to assess their evolutionary relationship. We also mapped the transposable element SINE-B1 on the chromosomes of P. gr. goeldii in order to investigate its distribution among individuals and evaluate its possible contribution to karyotype remodeling in this species. SINE-B1 showed a dispersed distribution along chromosome arms and was also detected at the pericentromeric regions of some chromosomes, including pair 1 and the sex chromosomes, which are involved in chromosome rearrangements. In addition, we describe a new cytotype for P. gr. goeldii, reinforcing the significant role of gross chromosomal rearrangements during the evolution of the genus. The results of FISH with SINE-B1 suggest that this issue should be more deeply investigated for a better understanding of its role in the mechanisms involved in the wide variety of Proechimys karyotypes.

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Synteny Conservation and Chromosome Rearrangements During Mammalian Evolution

Genetics ◽

10.1093/genetics/147.1.289 ◽

1997 ◽

Vol 147 (1) ◽

pp. 289-296 ◽

Cited By ~ 2

Author(s):

Jason Ehrlich ◽

David Sankoff ◽

Joseph H Nadeau

Keyword(s):

Genome Analysis ◽

Systematic Errors ◽

Chromosome Rearrangements ◽

Mammalian Evolution ◽

Comparative Genome Analysis ◽

Reciprocal Translocations ◽

Comparative Genome ◽

Strong Selection ◽

Synteny Conservation

Abstract An important problem in comparative genome analysis has been defining reliable measures of synteny conservation. The published analytical measures of synteny conservation have limitations. Nonindependence of comparisons, conserved and disrupted syntenies that are as yet unidentified, and redundant rearrangements lead to systematic errors that tend to overestimate the degree of conservation. We recently derived methods to estimate the total number of conserved syntenies within the genome, counting both those that have already been described and those that remain to be discovered. With this method, we show that ~65% of the conserved syntenies have already been identified for humans and mice, that rates of synteny disruption vary ~25-fold among mammalian lineages, and that despite strong selection against reciprocal translocations, inter-chromosome rearrangements occurred approximately fourfold more often than inversions and other intra-chromosome rearrangements, at least for lineages leading to humans and mice.

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SITE-SPECIFIC INSTABILITY IN DROSOPHILA MELANOGASTER: EVIDENCE FOR TRANSPOSITION OF DESTABILIZING ELEMENT

Genetics ◽

10.1093/genetics/101.3-4.461 ◽

1982 ◽

Vol 101 (3-4) ◽

pp. 461-476

Author(s):

Todd R Laverty ◽

J K Lim

Keyword(s):

Drosophila Melanogaster ◽

X Chromosome ◽

Lethal Mutation ◽

Chromosome Rearrangements ◽

Chromosome Break ◽

Secondary Mutation ◽

X Chromosomes ◽

Site Specific ◽

Normal Sequence ◽

Lethal Mutations

ABSTRACT In this study, we show that at least one lethal mutation at the 3F-4A region of the X chromosome can generate an array of chromosome rearrangements, all with one chromosome break in the 3F-4A region. The mutation at 3F-4A (secondary mutation) was detected in an X chromosome carrying a reverse mutation of an unstable lethal mutation, which was mapped in the 6F1-2 doublet (primary mutation). The primary lethal mutation at 6F1-2 had occurred in an unstable chromosome (Uc) described previously (Lim 1979). Prior to reversion, the 6F1-2 mutation had generated an array of chromosome rearrangements, all having one break in the 6F1-2 doublet (Lim 1979, 1980). In the X chromosomes carrying the 3F-4A secondary lethal mutation the 6F1-2 doublet was normal and stable, as was the 3F-4A region in the X chromosome carrying the primary lethal mutation. The disappearance of the instability having a set of genetic properties at one region (6F1-2) accompanied by its appearance elsewhere in the chromosome (3F-4A) implies that a transposition of the destabilizing element took place. The mutant at 3F-4A and other secondary mutants exhibited all but one (reinversion of an inversion to the normal sequence) of the eight properties of the primary lethal mutations. These observations support the view that a transposable destabilizing element is responsible for the hypermutability observed in the unstable chromosome and its derivaties.

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