1
|
Vicari MR, Bruschi DP, Cabral-de-Mello DC, Nogaroto V. Telomere organization and the interstitial telomeric sites involvement in insects and vertebrates chromosome evolution. Genet Mol Biol 2022; 45:e20220071. [DOI: 10.1590/1678-4685-gmb-2022-0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 09/24/2022] [Indexed: 11/16/2022] Open
|
2
|
Silva CEFE, Souza ÉMSD, Eler ES, Silva MNFD, Feldberg E. Comparison of the heterochromatin and telomeric sequences distribuition in chromosomes of 11 species of Amazonian marsupials (Didelphimorphia; Didelphidae). Genet Mol Biol 2020; 43:e20190357. [PMID: 32396598 PMCID: PMC7216969 DOI: 10.1590/1678-4685-gmb-2019-0357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/18/2020] [Indexed: 12/02/2022] Open
Abstract
In recent decades the diploid numbers recorded in the New World marsupials have
been widely discussed in the context of the processes of karyotype evolution in
these mammals. While Interstitial Telomeric Sequences (ITS) have long been
interpreted as remnants of chromosomal fusion, the biological role of these
features, together with their intraspecific variation, has raised a number of
questions. In the present study, we analyzed the karyotype of 11 species of
Amazonian didelphids, comparing the distribution of the heterochromatin with
that of the telomeric signals, and found that, in six species, the ITS coincided
with the blocks of heterochromatin. While ITS were found in the X chromosomes of
all Marmosa murina individuals, they were variable in all the
other species, representing a specific character of each lineage. Our results
support the conclusion that ITS may not always be a consequence of chromosomal
rearrangements, and that the mechanisms that produce them are still unclear.
Collapse
Affiliation(s)
| | | | - Eduardo Schmidt Eler
- Instituto Nacional de Pesquisas da Amazônia, Brazil; Universidade Anhembi Morumbi, Brazil
| | | | | |
Collapse
|
3
|
The methylation and telomere landscape in two families of marsupials with different rates of chromosome evolution. Chromosome Res 2018; 26:317-332. [PMID: 30539406 DOI: 10.1007/s10577-018-9593-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/22/2018] [Accepted: 11/23/2018] [Indexed: 02/07/2023]
Abstract
Two marsupial families exemplify divergent rates of karyotypic change. The Dasyurid family has an extremely conserved karyotype. In contrast, there is significant chromosomal variation within the Macropodidae family, best exemplified by members of the genus Petrogale (rock-wallabies). Both families are also distinguished by their telomere landscape (length and epigenetics), with the dasyurids having a unique telomere length dimorphism not observed in other marsupials and hypothesised to be regulated in a parent-of-origin fashion. Previous work has shown that proximal ends of chromosomes are enriched in cytosine methylation in dasyurids, but that the chromosomes of a macropod, the tammar wallaby, have DNA methylation enrichment of pericentric regions. Using a combination of telomere and 5-methylcytosine immunofluorescence staining, we investigated the telomere landscape of four dasyurid and three Petrogale species. As part of this study, we also further examined the parent-of-origin hypothesis for the regulation of telomere length dimorphism in dasyurids, using epigenetic modifications known to differentiate the active maternal X chromosome, including 5-methylcytosine methylation and histone modifications H3K4me2, H3K9ac and H4Kac. Our results give further support to the parent-of-origin hypothesis for the regulation of telomere length dimorphism in dasyurids, where the paternally derived X chromosome in females was associated with long telomeres and the maternally derived with short telomeres. In contrast to the tammar wallaby, rock-wallabies demonstrated a similar 5-methylcytosine staining pattern across all chromosomes to that of dasyurids, suggesting that DNA methylation of telomeric regions is not responsible for differences in the rates of chromosome evolution between these two families.
Collapse
|
4
|
Deakin JE. Chromosome Evolution in Marsupials. Genes (Basel) 2018; 9:E72. [PMID: 29415454 PMCID: PMC5852568 DOI: 10.3390/genes9020072] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 12/17/2022] Open
Abstract
Marsupials typically possess very large, distinctive chromosomes that make them excellent subjects for cytogenetic analysis, and the high level of conservation makes it relatively easy to track chromosome evolution. There are two speciose marsupial families with contrasting rates of karyotypic evolution that could provide insight into the mechanisms driving genome reshuffling and speciation. The family Dasyuridae displays exceptional karyotype conservation with all karyotyped species possessing a 2n = 14 karyotype similar to that predicted for the ancestral marsupial. In contrast, the family Macropodidae has experienced a higher rate of genomic rearrangement and one genus of macropods, the rock-wallabies (Petrogale), has experienced extensive reshuffling. For at least some recently diverged Petrogale species, there is still gene flow despite hybrid fertility issues, making this species group an exceptional model for studying speciation. This review highlights the unique chromosome features of marsupial chromosomes, particularly for these two contrasting families, and the value that a combined cytogenetics, genomics, and epigenomics approach will have for testing models of genome evolution and speciation.
Collapse
Affiliation(s)
- Janine E Deakin
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2617, Australia.
| |
Collapse
|
5
|
de Souza ÉMS, Gross MC, Silva CEFE, Sotero-Caio CG, Feldberg E. Heterochromatin variation and LINE-1 distribution in Artibeus (Chiroptera, Phyllostomidae) from Central Amazon, Brazil. COMPARATIVE CYTOGENETICS 2017; 11:613-626. [PMID: 29114357 PMCID: PMC5672158 DOI: 10.3897/compcytogen.v11i4.14562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/09/2017] [Indexed: 06/07/2023]
Abstract
Species in the subgenus Artibeus Leach, 1821 are widely distributed in Brazil. Conserved karyotypes characterize the group with identical diploid number and chromosome morphology. Recent studies suggested that the heterochromatin distribution and accumulation patterns can vary among species. In order to assess whether variation can also occur within species, we have analyzed the chromosomal distribution of constitutive heterochromatin in A. planirostris (Spix, 1823) and A. lituratus (Olfers, 1818) from Central Amazon (North Brazil) and contrasted our findings with those reported for other localities in Brazil. In addition, Ag-NOR staining and FISH with 18S rDNA, telomeric, and LINE-1 probes were performed to assess the potential role that these different repetitive markers had in shaping the current architecture of heterochromatic regions. Both species presented interindividual variation of constitutive heterochromatin. In addition, in A. planirostris the centromeres of most chromosomes are enriched with LINE-1, colocated with pericentromeric heterochromatin blocks. Overall, our data indicate that amplification and differential distribution of the investigated repetitive DNAs might have played a significant role in shaping the chromosome architecture of the subgenus Artibeus.
Collapse
Affiliation(s)
- Érica Martinha Silva de Souza
- Programa de Pós-graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Aleixo, 69.060-001 Manaus, AM, Brazil
- Laboratório de Genética Animal, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Aleixo, 69.060-001 Manaus, AM, Brazil
| | - Maria Claudia Gross
- Universidade Federal da Integração Latino Americana, Laboratório de Genética, Av. Tarquínio Joslin dos Santos, 1000, Jardim Universitário, 85857-190, Foz do Iguaçu, PR, Brazil
| | - Carlos Eduardo Faresin e Silva
- Programa de Pós-graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Aleixo, 69.060-001 Manaus, AM, Brazil
- Laboratório de Genética Animal, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Aleixo, 69.060-001 Manaus, AM, Brazil
| | - Cibele Gomes Sotero-Caio
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA 79409
- Laboratório de Genética e Citogenética Animal e Humana, Departamento de Genética, Universidade Federal de Pernambuco, Av. da Engenharia s/n; Cidade Universitária; CEP:50740-600; Recife-PE, Brazil
| | - Eliana Feldberg
- Laboratório de Genética Animal, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Aleixo, 69.060-001 Manaus, AM, Brazil
| |
Collapse
|
6
|
Bolzán AD. Interstitial telomeric sequences in vertebrate chromosomes: Origin, function, instability and evolution. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:51-65. [PMID: 28927537 DOI: 10.1016/j.mrrev.2017.04.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/13/2017] [Accepted: 04/17/2017] [Indexed: 12/21/2022]
Abstract
By definition, telomeric sequences are located at the very ends or terminal regions of chromosomes. However, several vertebrate species show blocks of (TTAGGG)n repeats present in non-terminal regions of chromosomes, the so-called interstitial telomeric sequences (ITSs), interstitial telomeric repeats or interstitial telomeric bands, which include those intrachromosomal telomeric-like repeats located near (pericentromeric ITSs) or within the centromere (centromeric ITSs) and those telomeric repeats located between the centromere and the telomere (i.e., truly interstitial telomeric sequences) of eukaryotic chromosomes. According with their sequence organization, localization and flanking sequences, ITSs can be classified into four types: 1) short ITSs, 2) subtelomeric ITSs, 3) fusion ITSs, and 4) heterochromatic ITSs. The first three types have been described mainly in the human genome, whereas heterochromatic ITSs have been found in several vertebrate species but not in humans. Several lines of evidence suggest that ITSs play a significant role in genome instability and evolution. This review aims to summarize our current knowledge about the origin, function, instability and evolution of these telomeric-like repeats in vertebrate chromosomes.
Collapse
Affiliation(s)
- Alejandro D Bolzán
- Laboratorio de Citogenética y Mutagénesis, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-UNLP-CONICET La Plata), C.C. 403, 1900 La Plata, Argentina; Facultad de Ciencias Naturales y Museo, UNLP, Calle 60 y 122, 1900 La Plata, Argentina.
| |
Collapse
|
7
|
Deakin JE. Implications of monotreme and marsupial chromosome evolution on sex determination and differentiation. Gen Comp Endocrinol 2017; 244:130-138. [PMID: 26431612 DOI: 10.1016/j.ygcen.2015.09.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/15/2015] [Accepted: 09/26/2015] [Indexed: 12/30/2022]
Abstract
Studies of chromosomes from monotremes and marsupials endemic to Australasia have provided important insight into the evolution of their genomes as well as uncovering fundamental differences in their sex determination/differentiation pathways. Great advances have been made this century into solving the mystery of the complicated sex chromosome system in monotremes. Monotremes possess multiple different X and Y chromosomes and a candidate sex determining gene has been identified. Even greater advancements have been made for marsupials, with reconstruction of the ancestral karyotype enabling the evolutionary history of marsupial chromosomes to be determined. Furthermore, the study of sex chromosomes in intersex marsupials has afforded insight into differences in the sexual differentiation pathway between marsupials and eutherians, together with experiments showing the insensitivity of the mammary glands, pouch and scrotum to exogenous hormones, led to the hypothesis that there is a gene (or genes) on the X chromosome responsible for the development of either pouch or scrotum. This review highlights the major advancements made towards understanding chromosome evolution and how this has impacted on our understanding of sex determination and differentiation in these interesting mammals.
Collapse
Affiliation(s)
- Janine E Deakin
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia.
| |
Collapse
|
8
|
Matoso Silva R, Adega F, Kjöllerström HJ, Labuschagne K, Kotze A, Fernandes C, Chaves R, do Mar Oom M. Classical and Molecular Cytogenetics of the Panther Genet Genetta maculata (Mammalia, Carnivora, Viverridae). Cytogenet Genome Res 2016; 149:274-281. [DOI: 10.1159/000450627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2016] [Indexed: 11/19/2022] Open
Abstract
Genets (Genetta) are a genus of African mammalian carnivorans with 14 currently recognized species, although taxonomic uncertainties remain, particularly regarding the number of species within the large-spotted genet complex. This study presents the first banded karyotype and molecular cytogenetic analysis of a genetically identified panther genet, Genetta maculata, the most common and widespread taxon of the large-spotted genet complex, with a wide distribution in sub-Saharan Africa. Sampled in Gauteng Province, South Africa, it could be assigned to the subspecies G. m. letabae on geographic grounds and had a similar karyotype (2n = 52, FNa = 96) to those published for a panther genet from Ethiopia and for the West African large-spotted genet G. pardina. Notably, the specimen had a different autosomal morphology (2 acrocentric chromosomes) from that previously attributed to letabae (a single acrocentric chromosome), but the latter assignment was uncertain because the studied individuals were captive born and assigned based solely on a presumed origin in the former Transvaal Province of South Africa. Fluorescence in situ hybridization with a telomere repeat probe revealed the presence of telomeric sequences in the centromeres of most chromosomes, the so-called interstitial telomeric sites (ITSs). Since genets seem to have a unique, highly rearranged karyotype among feliforms and relatively low interspecific karyotypic variation, and considering the known instability of ITSs, we suggest that the large amount of ITSs found here might be due to evolutionarily recent extensive genomic rearrangements. This study provides cytogenetic information that contributes to our understanding of chromosomal variation and genomic rearrangements in genets, and valuable baseline data for future studies of karyotype evolution in carnivores in general and viverrids in particular.
Collapse
|
9
|
Suárez-Villota EY, Haro RE, Vargas RA, Gallardo MH. The ancestral chromosomes of Dromiciops gliroides (Microbiotheridae), and its bearings on the karyotypic evolution of American marsupials. Mol Cytogenet 2016; 9:59. [PMID: 27489568 PMCID: PMC4971695 DOI: 10.1186/s13039-016-0270-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/25/2016] [Indexed: 11/12/2022] Open
Abstract
Background The low-numbered 14-chromosome karyotype of marsupials has falsified the fusion hypothesis claiming ancestrality from a 22-chromosome karyotype. Since the 14-chromosome condition of the relict Dromiciops gliroides is reminecent of ancestrality, its interstitial traces of past putative fusions and heterochromatin banding patterns were studied and added to available marsupials’ cytogenetic data. Fluorescent in situ hybridization (FISH) and self-genomic in situ hybridization (self-GISH) were used to detect telomeric and repetitive sequences, respectively. These were complemented with C-, fluorescent banding, and centromere immunodetection over mitotic spreads. The presence of interstitial telomeric sequences (ITS) and diploid numbers were reconstructed and mapped onto the marsupial phylogenetic tree. Results No interstitial, fluorescent signals, but clearly stained telomeric regions were detected by FISH and self-GISH. Heterochromatin distribution was sparse in the telomeric/subtelomeric regions of large submetacentric chromosomes. Large AT-rich blocks were detected in the long arm of four submetacentrics and CG-rich block in the telomeric regions of all chromosomes. The ancestral reconstructions both ITS presence and diploid numbers suggested that ITS are unrelated to fusion events. Conclusion Although the lack of interstitial signals in D. gliroides’ karyotype does not prove absence of past fusions, our data suggests its non-rearranged plesiomorphic condition. Electronic supplementary material The online version of this article (doi:10.1186/s13039-016-0270-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Elkin Y Suárez-Villota
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
| | - Ronie E Haro
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
| | - Rodrigo A Vargas
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
| | - Milton H Gallardo
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
| |
Collapse
|
10
|
Deakin JE, Kruger-Andrzejewska M. Marsupials as models for understanding the role of chromosome rearrangements in evolution and disease. Chromosoma 2016; 125:633-44. [PMID: 27255308 DOI: 10.1007/s00412-016-0603-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 05/19/2016] [Accepted: 05/23/2016] [Indexed: 12/28/2022]
Abstract
Chromosome rearrangements have been implicated in diseases, such as cancer, and speciation, but it remains unclear whether rearrangements are causal or merely a consequence of these processes. Two marsupial families with very different rates of karyotype evolution provide excellent models in which to study the role of chromosome rearrangements in a disease and evolutionary context. The speciose family Dasyuridae displays remarkable karyotypic conservation, with all species examined to date possessing nearly identical karyotypes. Despite the seemingly high degree of chromosome stability within this family, they appear prone to developing tumours, including transmissible devil facial tumours. In contrast, chromosome rearrangements have been frequent in the evolution of the species-rich family Macropodidae, which displays a high level of karyotypic diversity. In particular, the genus Petrogale (rock-wallabies) displays an extraordinary level of chromosome rearrangement among species. For six parapatric Petrogale species, it appears that speciation has essentially been caught in the act, providing an opportunity to determine whether chromosomal rearrangements are a cause or consequence of speciation in this system. This review highlights the reasons that these two marsupial families are excellent models for testing hypotheses for hotspots of chromosome rearrangement and deciphering the role of chromosome rearrangements in disease and speciation.
Collapse
Affiliation(s)
- Janine E Deakin
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2617, Australia.
| | | |
Collapse
|
11
|
Schmid M, Steinlein C. Chromosome Banding in Amphibia. XXXIV. Intrachromosomal Telomeric DNA Sequences in Anura. Cytogenet Genome Res 2016; 148:211-26. [PMID: 27233250 DOI: 10.1159/000446298] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2016] [Indexed: 11/19/2022] Open
Abstract
The mitotic chromosomes of 4 anuran species were examined by various classical banding techniques and by fluorescence in situ hybridization using a (TTAGGG)n repeat. Large intrachromosomal telomeric sequences (ITSs) were demonstrated in differing numbers and chromosome locations. A detailed comparison of the present results with numerous published and unpublished data allowed a consistent classification of the various categories of large ITSs present in the genomes of anurans and other vertebrates. The classification takes into consideration the total numbers of large ITSs in the karyotypes, their chromosomal locations and their specific distribution patterns. A new category of large ITSs was recognized to exist in anuran species. It consists of large clusters of ITSs located in euchromatic chromosome segments, which is in clear contrast to the large ITSs in heterochromatic chromosome regions known in vertebrates. The origin of the different categories of large ITSs in heterochromatic and euchromatic chromosome regions, their mode of distribution in the karyotypes and evolutionary fixation in the genomes, as well as their cytological detection are discussed.
Collapse
Affiliation(s)
- Michael Schmid
- Department of Human Genetics, University of Wx00FC;rzburg, Wx00FC;rzburg, Germany
| | | |
Collapse
|
12
|
Global DNA Methylation patterns on marsupial and devil facial tumour chromosomes. Mol Cytogenet 2015; 8:74. [PMID: 26435750 PMCID: PMC4591559 DOI: 10.1186/s13039-015-0176-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Accepted: 09/19/2015] [Indexed: 12/19/2022] Open
Abstract
Background Despite DNA methylation being one of the most widely studied epigenetic modifications in eukaryotes, only a few studies have examined the global methylation status of marsupial chromosomes. The emergence of devil facial tumour disease (DFTD), a clonally transmissible cancer spreading through the Tasmanian devil population, makes it a particularly pertinent time to determine the methylation status of marsupial and devil facial tumour chromosomes. DNA methylation perturbations are known to play a role in genome instability in human tumours. One of the interesting features of the devil facial tumour is its remarkable karyotypic stability over time as only four strains with minor karyotypic differences having been reported. The cytogenetic monitoring of devil facial tumour (DFT) samples collected over an eight year period and detailed molecular cytogenetic analysis performed on the different DFT strains enables chromosome rearrangements to be correlated with methylation status as the tumour evolves. Results We used immunofluorescent staining with an antibody to 5-methylcytosine on metaphase chromosomes prepared from fibroblast cells of three distantly related marsupials, including the Tasmanian devil, as well as DFTD chromosomes prepared from samples collected from different years and representing different karyotypic strains. Staining of chromosomes from male and female marsupial cell lines indicate species-specific differences in global methylation patterns but with the most intense staining regions corresponding to telomeric and/or centromeric regions of autosomes. In males, the X chromosome was hypermethylated as was one X in females. Similarly, telomeric regions on DFTD chromosomes and regions corresponding to material from one of the two X chromosomes were hypermethylated. No difference in global methylation in samples of the same strain taken in different years was observed. Conclusions The methylation patterns on DFTD chromosomes suggests that the hypermethylated active X was shattered in the formation of the tumour chromosomes, with atypical areas of methylation on DFTD chromosomes corresponding to locations of X chromosome material from the shattered X. The incredibly stable broad methylation patterns observed between strains and over time may reflect the overall genomic stability of the devil facial tumour. Electronic supplementary material The online version of this article (doi:10.1186/s13039-015-0176-x) contains supplementary material, which is available to authorized users.
Collapse
|
13
|
Interstitial Telomeric Motifs in Squamate Reptiles: When the Exceptions Outnumber the Rule. PLoS One 2015; 10:e0134985. [PMID: 26252002 PMCID: PMC4529230 DOI: 10.1371/journal.pone.0134985] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 07/15/2015] [Indexed: 12/19/2022] Open
Abstract
Telomeres are nucleoprotein complexes protecting the physical ends of linear eukaryotic chromosomes and therefore helping to ensure their stability and integrity. Additionally, telomeric sequences can be localized in non-terminal regions of chromosomes, forming so-called interstitial telomeric sequences (ITSs). ITSs are traditionally considered to be relics of chromosomal rearrangements and thus very informative in the reconstruction of the evolutionary history of karyotype formation. We examined the distribution of the telomeric motifs (TTAGGG)n using fluorescence in situ hybridization (FISH) in 30 species, representing 17 families of squamate reptiles, and compared them with the collected data from another 38 species from literature. Out of the 68 squamate species analyzed, 35 possess ITSs in pericentromeric regions, centromeric regions and/or within chromosome arms. We conclude that the occurrence of ITSs is rather common in squamates, despite their generally conserved karyotypes, suggesting frequent and independent cryptic chromosomal rearrangements in this vertebrate group.
Collapse
|
14
|
Patterns of rDNA and telomeric sequences diversification: contribution to repetitive DNA organization in Phyllostomidae bats. Genetica 2013; 142:49-58. [PMID: 24368540 DOI: 10.1007/s10709-013-9753-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/17/2013] [Indexed: 10/25/2022]
Abstract
Chromosomal organization and the evolution of genome architecture can be investigated by physical mapping of the genes for 45S and 5S ribosomal DNAs (rDNAs) and by the analysis of telomeric sequences. We studied 12 species of bats belonging to four subfamilies of the family Phyllostomidae in order to correlate patterns of distribution of heterochromatin and the multigene families for rDNA. The number of clusters for 45S gene ranged from one to three pairs, with exclusively location in autosomes, except for Carollia perspicillata that had in X chromosome. The 5S gene all the species studied had only one site located on an autosomal pair. In no species the 45S and 5S genes collocated. The fluorescence in situ hybridization (FISH) probe for telomeric sequences revealed fluorescence on all telomeres in all species, except in Carollia perspicillata. Non-telomeric sites in the pericentromeric region of the chromosomes were observed in most species, ranged from one to 12 pairs. Most interstitial telomeric sequences were coincident with heterochromatic regions. The results obtained in the present work indicate that different evolutionary mechanisms are acting in Phyllostomidae genome architecture, as well as the occurrence of Robertsonian fusion during the chromosomal evolution of bats without a loss of telomeric sequences. These data contribute to understanding the organization of multigene families and telomeric sequences on bat genome as well as the chromosomal evolutionary history of Phyllostomidae bats.
Collapse
|
15
|
The involvement of repetitive sequences in the remodelling of karyotypes: The Phodopus genomes (Rodentia, Cricetidae). Micron 2013; 46:27-34. [DOI: 10.1016/j.micron.2012.11.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 02/08/2023]
|
16
|
Deakin JE, Graves JAM, Rens W. The evolution of marsupial and monotreme chromosomes. Cytogenet Genome Res 2012; 137:113-29. [PMID: 22777195 DOI: 10.1159/000339433] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Marsupial and monotreme mammals fill an important gap in vertebrate phylogeny between reptile-mammal divergence 310 million years ago (mya) and the eutherian (placental) mammal radiation 105 mya. They possess many unique features including their distinctive chromosomes, which in marsupials are typically very large and well conserved between species. In contrast, monotreme genomes are divided into several large chromosomes and many smaller chromosomes, with a complicated sex chromosome system that forms a translocation chain in male meiosis. The application of molecular cytogenetic techniques has greatly advanced our understanding of the evolution of marsupial chromosomes and allowed the reconstruction of the ancestral marsupial karyotype. Chromosome painting and gene mapping have played a vital role in piecing together the puzzle of monotreme karyotypes, particularly their complicated sex chromosome system. Here, we discuss the significant insight into karyotype evolution afforded by the combination of recently sequenced marsupial and monotreme genomes with cytogenetic analysis, which has provided a greater understanding of the events that have shaped not only marsupial and monotreme genomes, but the genomes of all mammals.
Collapse
Affiliation(s)
- J E Deakin
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, Australia.
| | | | | |
Collapse
|
17
|
Abstract
The strategic importance of the genome sequence of the gray, short-tailed opossum, Monodelphis domestica, accrues from both the unique phylogenetic position of metatherian (marsupial) mammals and the fundamental biologic characteristics of metatherians that distinguish them from other mammalian species. Metatherian and eutherian (placental) mammals are more closely related to one another than to other vertebrate groups, and owing to this close relationship they share fundamentally similar genetic structures and molecular processes. However, during their long evolutionary separation these alternative mammals have developed distinctive anatomical, physiologic, and genetic features that hold tremendous potential for examining relationships between the molecular structures of mammalian genomes and the functional attributes of their components. Comparative analyses using the opossum genome have already provided a wealth of new evidence regarding the importance of noncoding elements in the evolution of mammalian genomes, the role of transposable elements in driving genomic innovation, and the relationships between recombination rate, nucleotide composition, and the genomic distributions of repetitive elements. The genome sequence is also beginning to enlarge our understanding of the evolution and function of the vertebrate immune system, and it provides an alternative model for investigating mechanisms of genomic imprinting. Equally important, availability of the genome sequence is fostering the development of new research tools for physical and functional genomic analyses of M. domestica that are expanding its versatility as an experimental system for a broad range of research applications in basic biology and biomedically oriented research.
Collapse
|
18
|
Mudry M, Nieves M, Bolzán A. Chromosomal localization of the telomeric (TTAGGG)n sequence in eight species of New World Primates (Neotropical Primates, Platyrrhini). Cytogenet Genome Res 2008; 119:221-4. [DOI: 10.1159/000112064] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2007] [Indexed: 02/03/2023] Open
|