scholarly journals Chromosome Evolution in Connection with Repetitive Sequences and Epigenetics in Plants

Genes ◽  
2017 ◽  
Vol 8 (10) ◽  
pp. 290 ◽  
Author(s):  
Shu-Fen Li ◽  
Ting Su ◽  
Guang-Qian Cheng ◽  
Bing-Xiao Wang ◽  
Xu Li ◽  
...  
Keyword(s):  
Chromosome Evolution ◽  
Repetitive Sequences

scholarly journals Cytogenetic Analysis and Chromosomal Mapping of Repetitive DNA in Melipona Species (Hymenoptera, Meliponini)

2019 ◽  
Vol 158 (4) ◽  
pp. 213-224 ◽  
Author(s):  
Natália M. Travenzoli ◽  
Bárbara A. Lima ◽  
Danon C. Cardoso ◽  
Jorge A. Dergam ◽  
Tânia M. Fernandes-Salomão ◽  
...  
Keyword(s):  
Stingless Bees ◽  
Chromosome Evolution ◽  
Repetitive Sequences ◽  
Sensu Stricto ◽  
Chromosomal Mapping ◽  
Evolutionary Constraints ◽  
Rdna Sites ◽  
Melipona Species ◽  
The Relationship ◽  
Evolutionary Lineages

Stingless bees of the genus Melipona are subdivided into 4 subgenera called Eomelipona, Melikerria, Melipona sensu stricto, and Michmelia according to species morphology. Cytogenetically, the species of the genus Melipona show variation in the amount and distribution of heterochromatin along their chromosomes and can be separated into 2 groups: the first with low content of heterochromatin and the second with high content of heterochromatin. These heterochromatin patterns and the number of chromosomes are characteristics exclusive to Melipona karyotypes that distinguish them from the other genera of the Meliponini. To better understand the karyotype organization in Melipona and the relationship among the subgenera, we mapped repetitive sequences and analyzed previously reported cytogenetic data with the aim to identify cytogenetic markers to be used for investigating the phylogenetic relationships and chromosome evolution in the genus. In general, Melipona species have 2n = 18 chromosomes, and the species of each subgenus share the same characteristics in relation to heterochromatin regions, DAPI/CMA3 fluorophores, and the number and distribution of 18S rDNA sites. Microsatellites were observed only in euchromatin regions, whereas the (TTAGG)6 repeats were found at telomeric sites in both groups. Our data indicate that in addition to the chromosome number, the karyotypes in Melipona could be separated into 2 groups that are characterized by conserved cytogenetic features and patterns that generally are shared by species within each subgenus, which may reflect evolutionary constraints. Our results agree with the morphological separation of the Melipona into 4 subgenera, suggesting that they must be independent evolutionary lineages.

scholarly journals Repetitive Sequence and Sex Chromosome Evolution in Vertebrates

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Tariq Ezaz ◽  
Janine E. Deakin
Keyword(s):  
Repetitive Dna ◽  
Sex Chromosomes ◽  
Repetitive Sequence ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Repetitive Sequences ◽  
Sex Chromosome Evolution ◽  
Genomic Changes ◽  
Heteromorphic Sex Chromosomes ◽  
Simple Repetitive Sequences

Sex chromosomes are the most dynamic entity in any genome having unique morphology, gene content, and evolution. They have evolved multiple times and independently throughout vertebrate evolution. One of the major genomic changes that pertain to sex chromosomes involves the amplification of common repeats. It is hypothesized that such amplification of repeats facilitates the suppression of recombination, leading to the evolution of heteromorphic sex chromosomes through genetic degradation of Y or W chromosomes. Although contrasting evidence is available, it is clear that amplification of simple repetitive sequences played a major role in the evolution of Y and W chromosomes in vertebrates. In this review, we present a brief overview of the repetitive DNA classes that accumulated during sex chromosome evolution, mainly focusing on vertebrates, and discuss their possible role and potential function in this process.

scholarly journals Chromosome mapping of repetitive sequences in Anostomidae species: implications for genomic and sex chromosome evolution

2012 ◽  
Vol 5 (1) ◽  
pp. 45 ◽  
Author(s):  
Edson Lourenço da Silva ◽  
Rafael Splendore de Borba ◽  
Patrícia Pasquali Parise-Maltempi
Keyword(s):  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Repetitive Sequences ◽  
Chromosome Mapping ◽  
Sex Chromosome Evolution

scholarly journals Genome-Wide Analysis of Transposable Elements and Satellite DNAs in Spinacia Species to Shed Light on Their Roles in Sex Chromosome Evolution

2021 ◽  
Vol 11 ◽  
Author(s):  
Ning Li ◽  
Xiaoyue Li ◽  
Jian Zhou ◽  
Li’ang Yu ◽  
Shufen Li ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Sex Chromosomes ◽  
Dna Sequences ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Repetitive Sequences ◽  
Chromosome 1 ◽  
Sex Chromosome Evolution ◽  
Satellite Dnas ◽  
Heteromorphic Sex Chromosomes

Sex chromosome evolution has mostly been studied in species with heteromorphic sex chromosomes. The Spinacia genus serves as an ideal model for investigating evolutionary mechanisms underlying the transition from homomorphic to heteromorphic sex chromosomes. Among evolutionary factors, repetitive sequences play multiple roles in sex chromosome evolution while their forces have not been fully explored in Spinacia species. Here, we identified major repetitive sequence classes in male and female genomes of Spinacia species and their ancestral relative sugar beet to elucidate the evolutionary processes of sex chromosome evolution using next-generation sequencing (NGS) data. Comparative analysis revealed that the repeat elements of Spinacia species are considerably higher than of sugar beet, especially the Ty3/Gypsy and Ty1/Copia retrotransposons. The long terminal repeat retroelements (LTR) Angela, Athila, and Ogre may be accounted for the higher proportion of repeats in the spinach genome. Comparison of the repeats proportion between female and male genomes of three Spinacia species indicated the different representation in Spinacia tetrandra samples but not in the S. oleracea or S. turkestanica samples. From these results, we speculated that emergence of repetitive DNA sequences may correlate the formation of sex chromosome and the transition from homomorphic sex chromosomes to heteromorphic sex chromosomes as heteromorphic sex chromosomes exclusively existed in Spinacia tetrandra. Three novel sugar beet-specific satellites were identified and confirmed by fluorescence in situ hybridization (FISH); six out of eight new spinach-specific satellites were mapped to the short arm of sex chromosomes. A total of 141 copies of SolSat01-171-s were found in the sex determination region (SDR). Thus, the accumulation of satellite DNA on the short arm of chromosome 1 may be involved in the sex chromosome evolution in Spinacia species. Our study provides a fundamental resource for understanding repeat sequences in Spinacia species and their roles in sex chromosome evolution.

scholarly journals Karyotypes and Sex Chromosomes in Two Australian Native Freshwater Fishes, Golden Perch (Macquaria ambigua) and Murray Cod (Maccullochella peelii) (Percichthyidae)

2019 ◽  
Vol 20 (17) ◽  
pp. 4244 ◽  
Author(s):  
Foyez Shams ◽  
Fiona Dyer ◽  
Ross Thompson ◽  
Richard P. Duncan ◽  
Jason D. Thiem ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Repetitive Sequences ◽  
Freshwater Fishes ◽  
Sex Chromosome Evolution ◽  
Acrocentric Chromosomes ◽  
Heterogametic Sex ◽  
Murray Cod ◽  
Australian Freshwater

Karyotypic data from Australian native freshwater fishes are scarce, having been described from relatively few species. Golden perch (Macquaria ambigua) and Murray cod (Maccullochella peelii) are two large-bodied freshwater fish species native to Australia with significant indigenous, cultural, recreational and commercial value. The arid landscape over much of these fishes’ range, coupled with the boom and bust hydrology of their habitat, means that these species have potential to provide useful evolutionary insights, such as karyotypes and sex chromosome evolution in vertebrates. Here we applied standard and molecular cytogenetic techniques to characterise karyotypes for golden perch and Murray cod. Both species have a diploid chromosome number 2n = 48 and a male heterogametic sex chromosome system (XX/XY). While the karyotype of golden perch is composed exclusively of acrocentric chromosomes, the karyotype of Murray cod consists of two submetacentric and 46 subtelocentric/acrocentric chromosomes. We have identified variable accumulation of repetitive sequences (AAT)10 and (CGG)10 along with diverse methylation patterns, especially on the sex chromosomes in both species. Our study provides a baseline for future cytogenetic analyses of other Australian freshwater fishes, especially species from the family Percichthyidae, to better understand their genome and sex chromosome evolution.

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