scholarly journals A Gradual Process of Recombination Restriction in the Evolutionary History of the Sex Chromosomes in Dioecious Plants

PLoS Biology ◽  
2004 ◽  
Vol 3 (1) ◽  
pp. e4 ◽  
Author(s):  
Michael Nicolas ◽  
Gabriel Marais ◽  
Vladka Hykelova ◽  
Bohuslav Janousek ◽  
Valérie Laporte ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Evolutionary History ◽  
Dioecious Plants ◽  
Gradual Process ◽  
History Of

The conservation of number and location of 18S sites indicates the relative stability of rDNA in species of Pentatomomorpha (Heteroptera)

Genome ◽  
2013 ◽  
Vol 56 (7) ◽  
pp. 425-429 ◽  
Author(s):  
Vanessa Bellini Bardella ◽  
Thiago Fernandes ◽  
André Luís Laforga Vanzela
Keyword(s):  
Sex Chromosomes ◽  
18S Rdna ◽  
Fluorescent In Situ Hybridization ◽  
Evolutionary History ◽  
Conclusive Evidence ◽  
Fish Analysis ◽  
Comparative Cytogenetics ◽  
Rdna Sites ◽  
History Of

Fluorescent in situ hybridization (FISH) with rDNA probes has been used for comparative cytogenetics studies in different groups of organisms. Although heteropterans are a large suborder within Hemiptera, studies using rDNA are limited to the infraorder Cimicomorpha, in which rDNA sites are present in the autosomes or sex chromosomes. We isolated and sequenced a conserved 18S rDNA region of Antiteuchus tripterus (Pentatomidae) and used it as a probe against chromosomes of 25 species belonging to five different families of Pentatomomorpha. The clone pAt05, with a length of 736 bp, exhibited a conserved stretch of 590 bp. FISH analysis with the probe pAt05 always demonstrated hybridization signals in sub-terminal positions, except for Euschistus heros. Apparently, there is a tendency for 18S rDNA sites to locate in autosomes, except for Leptoglossus gonagra and Euryophthalmus rufipennis, which showed signals in the m- and sex chromosomes, respectively. Although FISH has produced evidence that rearrangements are involved in rDNA repositioning, whether in different autosomes or between sex and m-chromosomes, we have no conclusive evidence of what were the pathways of these rearrangements based on the evolutionary history of the species studied here. Nevertheless, the diversity in the number of species analyzed here showed a tendency of 18S rDNA to remain among the autosomes.

scholarly journals Complex evolutionary history of the Y chromosome in flies of the Drosophila obscura species group

2019 ◽  
Author(s):  
Ryan Bracewell ◽  
Doris Bachtrog
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Evolutionary History ◽  
Sex Chromosome ◽  
Species Group ◽  
Genomic Environment ◽  
History Of ◽  
Chromosome Formation ◽  
Dramatic Variation ◽  
Complex Evolutionary History

The Drosophila obscura species group shows dramatic variation in karyotype, including transitions among sex chromosomes. Members of the affinis and pseudoobscura subgroups contain a neo-X chromosome (a fusion of the X with an autosome), and it was shown that ancestral Y genes of Drosophila have become autosomal in species that contain the neo-X. Detailed analysis in species of the pseudoobscura subgroup revealed a translocation of ancestral Y genes to the small dot chromosome of that group. Here, we show that the Y-dot translocation is restricted to the pseudoobscura subgroup, and translocation of Y genes in the affinis subgroup followed a different route. We find that most ancestral Y genes moved independently to autosomal or X-linked locations in different taxa of the affinis subgroup, and we propose a dynamic model of sex chromosome formation and turnover in the obscura species group. Our results show that Y genes can find unique paths to escape an unfavorable genomic environment.

scholarly journals Complex Evolutionary History of the Y Chromosome in Flies of the Drosophila obscura Species Group

2020 ◽  
Vol 12 (5) ◽  
pp. 494-505
Author(s):  
Ryan Bracewell ◽  
Doris Bachtrog
Keyword(s):  
Detailed Analysis ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Evolutionary History ◽  
Sex Chromosome ◽  
Species Group ◽  
History Of ◽  
Chromosome Formation ◽  
Dramatic Variation ◽  
Complex Evolutionary History

Abstract The Drosophila obscura species group shows dramatic variation in karyotype, including transitions among sex chromosomes. Members of the affinis and pseudoobscura subgroups contain a neo-X chromosome (a fusion of the X with an autosome), and ancestral Y genes have become autosomal in species harboring the neo-X. Detailed analysis of species in the pseudoobscura subgroup revealed that ancestral Y genes became autosomal through a translocation to the small dot chromosome. Here, we show that the Y-dot translocation is restricted to the pseudoobscura subgroup, and translocation of ancestral Y genes in the affinis subgroup likely followed a different route. We find that most ancestral Y genes have translocated to unique autosomal or X-linked locations in different taxa of the affinis subgroup, and we propose a dynamic model of sex chromosome formation and turnover in the obscura species group. Our results suggest that Y genes can find unique paths to escape unfavorable genomic environments that form after sex chromosome–autosome fusions.

scholarly journals Dynamic evolutionary history and gene content of sex chromosomes across diverse songbirds

2018 ◽  
Author(s):  
Luo-hao Xu ◽  
Gabriel Auer ◽  
Valentina Peona ◽  
Alexander Suh ◽  
Yuan Deng ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Sex Chromosomes ◽  
Evolutionary History ◽  
Sequence Divergence ◽  
Species Number ◽  
Recombination Suppression ◽  
Chromosome Inversion ◽  
Linked Gene ◽  
Accelerated Evolution ◽  
History Of

AbstractSongbirds have a species number almost equivalent to that of mammals, and are classic models for studying mechanisms of speciation and sexual selection. Sex chromosomes are hotspots of both processes, yet their evolutionary history in songbirds remains unclear. To elucidate that, we characterize female genomes of 11 songbird species having ZW sex chromosomes, with 5 genomes of bird-of-paradise species newly produced in this work. We conclude that songbird sex chromosomes have undergone at least four steps of recombination suppression before their species radiation, producing a gradient pattern of pairwise sequence divergence termed ‘evolutionary strata’. Interestingly, the latest stratum probably emerged due to a songbird-specific burst of retrotransposon CR1-E1 elements at its boundary, or chromosome inversion on the W chromosome. The formation of evolutionary strata has reshaped the genomic architecture of both sex chromosomes. We find stepwise variations of Z-linked inversions, repeat and GC contents, as well as W-linked gene loss rate that are associated with the age of strata. Over 30 W-linked genes have been preserved for their essential functions, indicated by their higher and broader expression of orthologs in lizard than those of other sex-linked genes. We also find a different degree of accelerated evolution of Z-linked genes vs. autosomal genes among different species, potentially reflecting their diversified intensity of sexual selection. Our results uncover the dynamic evolutionary history of songbird sex chromosomes, and provide novel insights into the mechanisms of recombination suppression.

scholarly journals Uncovering the evolutionary history of neo-XY sex chromosomes in the grasshopper Ronderosia bergii (Orthoptera, Melanoplinae) through satellite DNA analysis

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Octavio M. Palacios-Gimenez ◽  
Diogo Milani ◽  
Bernardo Lemos ◽  
Elio R. Castillo ◽  
Dardo A. Martí ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Satellite Dna ◽  
Evolutionary History ◽  
Dna Analysis ◽  
History Of

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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