Differential rates of genic and chromosomal evolution in bats of the family Rhinolophidae

Genome ◽  
1988 ◽  
Vol 30 (3) ◽  
pp. 326-335 ◽  
Author(s):  
M. B. Qumsiyeh ◽  
R. D. Owen ◽  
R. K. Chesser
Keyword(s):  
Chromosomal Rearrangements ◽  
Chromosomal Evolution ◽  
Starch Gel Electrophoresis ◽  
Apparent Lack ◽  
Evolutionary Forces ◽  
Gross Chromosomal Rearrangements ◽  
Morphological Criteria ◽  
Electrophoretic Data ◽  
Chromosomal Data ◽  
Well Differentiated

Data for nondifferentially stained chromosomes from 10 species of Rhinolophus (Chiroptera: Rhinolophidae) suggest a conserved chromosomal evolution. G-banded chromosomes for three well differentiated species (Rhinolophus hipposideros, Rhinolophus blasii, and Rhinolophus acuminatus) corroborate a low level of gross chromosomal rearrangements. Additionally, a comparison between G-banded chromosomes of Rhinolophus (Rhinolophidae) and Hipposideros (Hipposideridae) suggests extreme conservatism in chromosomal arms between these two distantly related groups. On the other hand, we report extensive genie divergence as assayed by starch gel electrophoresis among these 10 species, and between Rhinolophus and two hipposiderid genera (Hipposideros and Aselliscus). The present chromosomal data are not sufficient for phylogenetic analysis. Phylogenies based on electrophoretic data are in many aspects discordant with those based on the classical morphological criteria. Different (and as yet not clearly understood) evolutionary forces affecting chromosomal, morphologic, and electrophoretic variation may be the reason for the apparent lack of concordance in these independent data sets.Key words: Rhinolophidae, chromosomes, electrophoresis, phylogeny.

scholarly journals Genome-Wide Amplifications Caused by Chromosomal Rearrangements Play a Major Role in the Adaptive Evolution of Natural Yeast

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 1745-1759 ◽  
Author(s):  
Juan J Infante ◽  
Kenneth M Dombek ◽  
Laureana Rebordinos ◽  
Jesús M Cantoral ◽  
Elton T Young
Keyword(s):  
Adaptive Evolution ◽  
Chromosomal Rearrangements ◽  
Sexual Isolation ◽  
Chromosomal Evolution ◽  
Double Strand Breaks ◽  
Chromosomal Dna ◽  
Strand Breaks ◽  
Yeast Strains ◽  
Gross Chromosomal Rearrangements ◽  
Flor Yeast

Abstract The relative importance of gross chromosomal rearrangements to adaptive evolution has not been precisely defined. The Saccharomyces cerevisiae flor yeast strains offer significant advantages for the study of molecular evolution since they have recently evolved to a high degree of specialization in a very restrictive environment. Using DNA microarray technology, we have compared the genomes of two prominent variants of S. cerevisiae flor yeast strains. The strains differ from one another in the DNA copy number of 116 genomic regions that comprise 38% of the genome. In most cases, these regions are amplicons flanked by repeated sequences or other recombination hotspots previously described as regions where double-strand breaks occur. The presence of genes that confer specific characteristics to the flor yeast within the amplicons supports the role of chromosomal rearrangements as a major mechanism of adaptive evolution in S. cerevisiae. We propose that nonallelic interactions are enhanced by ethanol- and acetaldehyde-induced double-strand breaks in the chromosomal DNA, which are repaired by pathways that yield gross chromosomal rearrangements. This mechanism of chromosomal evolution could also account for the sexual isolation shown among the flor yeast.

Chromosomal Evolution in the Diplodactylinae (Gekkonidae, Reptilia) .1. Evolutionary Relationships and Patterns of Change

1987 ◽  
Vol 35 (5) ◽  
pp. 507 ◽  
Author(s):  
M King
Keyword(s):  
Pericentric Inversion ◽  
Chromosomal Rearrangements ◽  
Chromosomal Evolution ◽  
Species Group ◽  
Individual Species ◽  
Ancestral Karyotype ◽  
Chromosome Fusion ◽  
Gross Chromosomal Rearrangements ◽  
Extant Species ◽  
Pericentric Inversions

A chromosomal analysis of 47 species of diplodactyline gekkos indicates that these are a monophyletic assemblage derived from a 2n = 38 acrocentric ancestral karyotype. Four major clades are present, the first possessing the ancestral karyotype. The remainder are defined by the possession of a series of shared derived chromosomal rearrangements, or by the type of chromosome change. The first of these derived clades includes the subgenus Strophurus, which has five fixed, presumed pericentric inversion differences. The second includes members of the D. vittatus species group. Here, a number of chromosome fusions have been established which appear to have been associated with speciation. The third derived clade is distinguished by 19 fixed, presumed pericentric inversions, and includes the genera, Oedura, Rhacodactylus, Bavayia, Pseudothecadactylus, Carphodactylus and Hoplodactylus. It is argued that the 2n=38 acrocentric karyotype common to many of the species is the ancestral karyomorph, and the modifications of this format have been achieved by both chromosome fusion and pericentric inversion. The decision that this is the ancestral karyomorph was based on its dominance in extant species; the fact that similar karyotypes are present in other gekkonid subfamilies (effective out-groups), that 2n =38 all acrocentric ancestral karyotypes are also found in some other lizard families, and that such a diversity of rearrangements was established, provide arguments against any other viable ancestral format. Two discrete modes of chromosomal repatterning are found in the Diplodactylinae: the fixation of presumptive multiple pericentric inversions, producing a karyomorph which characterises large groups of species; and the fixation of fusion or presumptive inversion differences which distinguish individual species or chromosome races. The latter appear to have been associated with speciation. It is clear that in certain groups, such as the Strophurus species group (the members of which all share a derived karyomorph defined by the presence of five inverted chromosomes), speciation has proceeded without gross chromosomal rearrangements.

SINE-B1 Distribution and Chromosome Rearrangements in the South American Proechimys gr. goeldii (Echimyidae, Rodentia)

2021 ◽  
pp. 1-8
Author(s):  
Naiara P. Araújo ◽  
Radarane S. Sena ◽  
Cibele R. Bonvicino ◽  
Gustavo C.S. Kuhn ◽  
Marta Svartman
Keyword(s):  
Transposable Element ◽  
Genome Evolution ◽  
Significant Role ◽  
Sex Chromosomes ◽  
Chromosomal Rearrangements ◽  
Evolutionary Relationship ◽  
Chromosome Rearrangements ◽  
South American ◽  
Gross Chromosomal Rearrangements

<i>Proechimys</i> species are remarkable for their extensive chromosome rearrangements, representing a good model to understand genome evolution. Herein, we cytogenetically analyzed 3 different cytotypes of <i>Proechimys</i> gr. <i>goeldii</i> to assess their evolutionary relationship. We also mapped the transposable element SINE-B1 on the chromosomes of <i>P.</i> gr. <i>goeldii</i> 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 <i>P.</i> gr. <i>goeldii</i>, 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 <i>Proechimys</i> karyotypes.

RELATIONSHIP OF TAXA IN THE GENUS MEDICAGO AS REVEALED BY HYBRIDIZATION. I. M. STRIATA × M. LITTORALIS

1968 ◽  
Vol 10 (2) ◽  
pp. 263-275 ◽  
Author(s):  
K. Lesins ◽  
A. Erac
Keyword(s):  
High Mortality ◽  
Genetic Factor ◽  
Genetic Factors ◽  
Chromosomal Rearrangements ◽  
Cytoplasmic Factor ◽  
Reciprocal Crosses ◽  
Gross Chromosomal Rearrangements ◽  
Coiling Direction ◽  
Chlorophyll Deficiencies ◽  
Relationship Of

In crosses between the two taxa Medicago striata Bast, and M. littoralis Rohde a high mortality of gametes and seedlings, and sterility of some plants were noted which were not related to gross chromosomal rearrangements. Although the F1, F2 and F3 generations from reciprocal crosses differed in chlorophyll deficiencies (indicating a cytoplasmic influence) a genic cause became evident from segregations for chlorophyll characters in the F2 and F3. Transference of the cytoplasmic factor by the pollen is indicative.Segregation for pod coiling direction indicated that the character was determined by one or two genetic factors of which the clockwise coiling direction is recessive. The spininess appeared to be determined by one genetic factor, of which the spineless allele is recessive.On the basis of genetic differences (especially on the built-in repulsion systems for normal chlorophyll development of opposite species) the two taxa should be considered two different species.

scholarly journals Meiosis-specific recombinase Dmc1 is a potent inhibitor of the Srs2 antirecombinase

2018 ◽  
Vol 115 (43) ◽  
pp. E10041-E10048 ◽  
Author(s):  
J. Brooks Crickard ◽  
Kyle Kaniecki ◽  
Youngho Kwon ◽  
Patrick Sung ◽  
Eric C. Greene
Keyword(s):  
Chromosome Segregation ◽  
Single Molecule ◽  
Atp Hydrolysis ◽  
Potent Inhibitor ◽  
Chromosomal Rearrangements ◽  
Motor Protein ◽  
Product Formation ◽  
Gross Chromosomal Rearrangements ◽  
Strand Annealing ◽  
Hydrolysis Activity

Cross-over recombination products are a hallmark of meiosis because they are necessary for accurate chromosome segregation and they also allow for increased genetic diversity during sexual reproduction. However, cross-overs can also cause gross chromosomal rearrangements and are therefore normally down-regulated during mitotic growth. The mechanisms that enhance cross-over product formation upon entry into meiosis remain poorly understood. In Saccharomyces cerevisiae, the Superfamily 1 (Sf1) helicase Srs2, which is an ATP hydrolysis-dependent motor protein that actively dismantles recombination intermediates, promotes synthesis-dependent strand annealing, the result of which is a reduction in cross-over recombination products. Here, we show that the meiosis-specific recombinase Dmc1 is a potent inhibitor of Srs2. Biochemical and single-molecule assays demonstrate that Dmc1 acts by inhibiting Srs2 ATP hydrolysis activity, which prevents the motor protein from undergoing ATP hydrolysis-dependent translocation on Dmc1-bound recombination intermediates. We propose a model in which Dmc1 helps contribute to cross-over formation during meiosis by antagonizing the antirecombinase activity of Srs2.

Patterns of genome duplication within the Brassica napus genome

Genome ◽  
2003 ◽  
Vol 46 (2) ◽  
pp. 291-303 ◽  
Author(s):  
I A.P Parkin ◽  
A G Sharpe ◽  
D J Lydiate
Keyword(s):  
Brassica Napus ◽  
Genome Duplication ◽  
Chromosomal Rearrangements ◽  
Centric Fusion ◽  
Linkage Groups ◽  
Gross Chromosomal Rearrangements ◽  
A Genome ◽  
C Genome ◽  
Homologous Locus ◽  
Duplicate Loci

The progenitor diploid genomes (A and C) of the amphidiploid Brassica napus are extensively duplicated with 73% of genomic clones detecting two or more duplicate sequences within each of the diploid genomes. This comprehensive duplication of loci is to be expected in a species that has evolved through a polyploid ancestor. The majority of the duplicate loci within each of the diploid genomes were found in distinct linkage groups as collinear blocks of linked loci, some of which had undergone a variety of rearrangements subsequent to duplication, including inversions and translocations. A number of identical rearrangements were observed in the two diploid genomes, suggesting they had occurred before the divergence of the two species. A number of linkage groups displayed an organization consistent with centric fusion and (or) fission, suggesting this mechanism may have played a role in the evolution of Brassica genomes. For almost every genetically mapped locus detected in the A genome a homologous locus was found in the C genome; the collinear arrangement of these homologous markers allowed the primary regions of homoeology between the two genomes to be identified. At least 16 gross chromosomal rearrangements differentiated the two diploid genomes during their divergence from a common ancestor.Key words: genome evolution, Brassicaeae, polyploidy, homoeologous linkage groups.

scholarly journals Heterochromatin suppresses gross chromosomal rearrangements at centromeres by repressing Tfs1/TFIIS-dependent transcription

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Akiko K. Okita ◽  
Faria Zafar ◽  
Jie Su ◽  
Dayalini Weerasekara ◽  
Takuya Kajitani ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Gross Chromosomal Rearrangements
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