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Ruth B. Phillips - One of the best experts on this subject based on the ideXlab platform.

  • assignment of chinook salmon oncorhynchus tshawytscha linkage groups to specific Chromosomes reveals a karyotype with multiple rearrangements of the Chromosome arms of rainbow trout oncorhynchus mykiss
    G3: Genes Genomes Genetics, 2013
    Co-Authors: Ruth B. Phillips, Linda K Park, Kerry A Naish
    Abstract:

    The Chinook salmon genetic linkage groups have been assigned to specific Chromosomes using fluorescence in situ hybridization with bacterial artificial Chromosome probes containing genetic markers Mapped to each linkage group in Chinook salmon and rainbow trout. Comparison of the Chinook salmon Chromosome Map with that of rainbow trout provides strong evidence for conservation of large syntenic blocks in these species, corresponding to entire Chromosome arms in the rainbow trout as expected. In almost every case, the markers were found at approximately the same location on the Chromosome arm in each species, suggesting conservation of marker order on the Chromosome arms of the two species in most cases. Although theoretically a few centric fissions could convert the karyotype of rainbow trout (2N = 58–64) into that of Chinook salmon (2N = 68) or vice versa, our data suggest that Chromosome arms underwent multiple centric fissions and subsequent new centric fusions to form the current karyotypes. The morphology of only approximately one-third of the Chromosome pairs have been conserved between the two species.

  • assignment of atlantic salmon salmo salar linkage groups to specific Chromosomes conservation of large syntenic blocks corresponding to whole Chromosome arms in rainbow trout oncorhynchus mykiss
    BMC Genetics, 2009
    Co-Authors: Roy G Danzmann, Ruth B. Phillips, Kimberly A. Keatley, Matthew R. Morasch, Abigail B. Ventura, Krzysztof P. Lubieniecki, Ben F. Koop, William S. Davidson
    Abstract:

    Most teleost species, especially freshwater groups such as the Esocidae which are the closest relatives of salmonids, have a karyotype comprising 25 pairs of acrocentric Chromosomes and 48–52 Chromosome arms. After the common ancestor of salmonids underwent a whole genome duplication, its karyotype would have 100 Chromosome arms, and this is reflected in the modal range of 96–104 seen in extant salmonids (e.g., rainbow trout). The Atlantic salmon is an exception among the salmonids as it has 72–74 Chromosome arms and its karyotype includes 12 pairs of large acrocentric Chromosomes, which appear to be the result of tandem fusions. The purpose of this study was to integrate the Atlantic salmon's linkage Map and karyotype and to compare the Chromosome Map with that of rainbow trout. The Atlantic salmon genetic linkage groups were assigned to specific Chromosomes in the European subspecies using fluorescence in situ hybridization with BAC probes containing genetic markers Mapped to each linkage group. The genetic linkage groups were larger for metacentric Chromosomes compared to acrocentric Chromosomes of similar size. Comparison of the Atlantic salmon Chromosome Map with that of rainbow trout provides strong evidence for conservation of large syntenic blocks in these species, corresponding to entire Chromosome arms in the rainbow trout. It had been suggested that some of the large acrocentric Chromosomes in Atlantic salmon are the result of tandem fusions, and that the small blocks of repetitive DNA in the middle of the arms represent the sites of Chromosome fusions. The finding that the chromosomal regions on either side of the blocks of repetitive DNA within the larger acrocentric Chromosomes correspond to different rainbow trout Chromosome arms provides support for this hypothesis.

  • Assignment of Atlantic salmon ( Salmo salar) linkage groups to specific Chromosomes: Conservation of large syntenic blocks corresponding to whole Chromosome arms in rainbow trout ( Oncorhynchus mykiss )
    BMC Genetics, 2009
    Co-Authors: Ruth B. Phillips, Roy G Danzmann, Kimberly A. Keatley, Matthew R. Morasch, Abigail B. Ventura, Krzysztof P. Lubieniecki, Ben F. Koop, William S. Davidson
    Abstract:

    Background: Most teleost species, especially freshwater groups such as the Esocidae which are the closest relatives of salmonids, have a karyotype comprising 25 pairs of acrocentric Chromosomes and 48– 52 Chromosome arms. After the common ancestor of salmonids underwent a whole genome duplication, its karyotype would have 100 Chromosome arms, and this is reflected in the modal range of 96–104 seen in extant salmonids (e.g., rainbow trout). The Atlantic salmon is an exception among the salmonids as it has 72–74 Chromosome arms and its karyotype includes 12 pairs of large acrocentric Chromosomes, which appear to be the result of tandem fusions. The purpose of this study was to integrate the Atlantic salmon's linkage Map and karyotype and to compare the Chromosome Map with that of rainbow trout. Results: The Atlantic salmon genetic linkage groups were assigned to specific Chromosomes in the European subspecies using fluorescence in situ hybridization with BAC probes containing genetic markers Mapped to each linkage group. The genetic linkage groups were larger for metacentric Chromosomes compared to acrocentric Chromosomes of similar size. Comparison of the Atlantic salmon Chromosome Map with that of rainbow trout provides strong evidence for conservation of large syntenic blocks in these species, corresponding to entire Chromosome arms in the rainbow trout. Conclusion: It had been suggested that some of the large acrocentric Chromosomes in Atlantic salmon are the result of tandem fusions, and that the small blocks of repetitive DNA in the middle of the arms represent the sites of Chromosome fusions. The finding that the chromosomal regions on either side of the blocks of repetitive DNA within the larger acrocentric Chromosomes correspond to different rainbow trout Chromosome arms provides support for this hypothesis.

William S. Davidson - One of the best experts on this subject based on the ideXlab platform.

  • assignment of atlantic salmon salmo salar linkage groups to specific Chromosomes conservation of large syntenic blocks corresponding to whole Chromosome arms in rainbow trout oncorhynchus mykiss
    BMC Genetics, 2009
    Co-Authors: Roy G Danzmann, Ruth B. Phillips, Kimberly A. Keatley, Matthew R. Morasch, Abigail B. Ventura, Krzysztof P. Lubieniecki, Ben F. Koop, William S. Davidson
    Abstract:

    Most teleost species, especially freshwater groups such as the Esocidae which are the closest relatives of salmonids, have a karyotype comprising 25 pairs of acrocentric Chromosomes and 48–52 Chromosome arms. After the common ancestor of salmonids underwent a whole genome duplication, its karyotype would have 100 Chromosome arms, and this is reflected in the modal range of 96–104 seen in extant salmonids (e.g., rainbow trout). The Atlantic salmon is an exception among the salmonids as it has 72–74 Chromosome arms and its karyotype includes 12 pairs of large acrocentric Chromosomes, which appear to be the result of tandem fusions. The purpose of this study was to integrate the Atlantic salmon's linkage Map and karyotype and to compare the Chromosome Map with that of rainbow trout. The Atlantic salmon genetic linkage groups were assigned to specific Chromosomes in the European subspecies using fluorescence in situ hybridization with BAC probes containing genetic markers Mapped to each linkage group. The genetic linkage groups were larger for metacentric Chromosomes compared to acrocentric Chromosomes of similar size. Comparison of the Atlantic salmon Chromosome Map with that of rainbow trout provides strong evidence for conservation of large syntenic blocks in these species, corresponding to entire Chromosome arms in the rainbow trout. It had been suggested that some of the large acrocentric Chromosomes in Atlantic salmon are the result of tandem fusions, and that the small blocks of repetitive DNA in the middle of the arms represent the sites of Chromosome fusions. The finding that the chromosomal regions on either side of the blocks of repetitive DNA within the larger acrocentric Chromosomes correspond to different rainbow trout Chromosome arms provides support for this hypothesis.

  • Assignment of Atlantic salmon ( Salmo salar) linkage groups to specific Chromosomes: Conservation of large syntenic blocks corresponding to whole Chromosome arms in rainbow trout ( Oncorhynchus mykiss )
    BMC Genetics, 2009
    Co-Authors: Ruth B. Phillips, Roy G Danzmann, Kimberly A. Keatley, Matthew R. Morasch, Abigail B. Ventura, Krzysztof P. Lubieniecki, Ben F. Koop, William S. Davidson
    Abstract:

    Background: Most teleost species, especially freshwater groups such as the Esocidae which are the closest relatives of salmonids, have a karyotype comprising 25 pairs of acrocentric Chromosomes and 48– 52 Chromosome arms. After the common ancestor of salmonids underwent a whole genome duplication, its karyotype would have 100 Chromosome arms, and this is reflected in the modal range of 96–104 seen in extant salmonids (e.g., rainbow trout). The Atlantic salmon is an exception among the salmonids as it has 72–74 Chromosome arms and its karyotype includes 12 pairs of large acrocentric Chromosomes, which appear to be the result of tandem fusions. The purpose of this study was to integrate the Atlantic salmon's linkage Map and karyotype and to compare the Chromosome Map with that of rainbow trout. Results: The Atlantic salmon genetic linkage groups were assigned to specific Chromosomes in the European subspecies using fluorescence in situ hybridization with BAC probes containing genetic markers Mapped to each linkage group. The genetic linkage groups were larger for metacentric Chromosomes compared to acrocentric Chromosomes of similar size. Comparison of the Atlantic salmon Chromosome Map with that of rainbow trout provides strong evidence for conservation of large syntenic blocks in these species, corresponding to entire Chromosome arms in the rainbow trout. Conclusion: It had been suggested that some of the large acrocentric Chromosomes in Atlantic salmon are the result of tandem fusions, and that the small blocks of repetitive DNA in the middle of the arms represent the sites of Chromosome fusions. The finding that the chromosomal regions on either side of the blocks of repetitive DNA within the larger acrocentric Chromosomes correspond to different rainbow trout Chromosome arms provides support for this hypothesis.

Fengtang Yang - One of the best experts on this subject based on the ideXlab platform.

  • a first generation comparative Chromosome Map between guinea pig cavia porcellus and humans
    PLOS ONE, 2015
    Co-Authors: Svetlana A Romanenko, Polina L Perelman, Alexander S. Graphodatsky, Natalia A Serdyukova, Wenhui Nie, Thomas Liehr, Roscoe Stanyon, Vladimir A Trifonov, Patricia C M Obrien, Fengtang Yang
    Abstract:

    The domesticated guinea pig, Cavia porcellus (Hystricomorpha, Rodentia), is an important laboratory species and a model for a number of human diseases. Nevertheless, genomic tools for this species are lacking; even its karyotype is poorly characterized. The guinea pig belongs to Hystricomorpha, a widespread and important group of rodents; so far the Chromosomes of guinea pigs have not been compared with that of other hystricomorph species or with any other mammals. We generated full sets of Chromosome-specific painting probes for the guinea pig by flow sorting and microdissection, and for the first time, Mapped the chromosomal homologies between guinea pig and human by reciprocal Chromosome painting. Our data demonstrate that the guinea pig karyotype has undergone extensive rearrangements: 78 synteny-conserved human autosomal segments were delimited in the guinea pig genome. The high rate of genome evolution in the guinea pig may explain why the HSA7/16 and HSA16/19 associations presumed ancestral for eutherians and the three syntenic associations (HSA1/10, 3/19, and 9/11) considered ancestral for rodents were not found in C. porcellus. The comparative Chromosome Map presented here is a starting point for further development of physical and genetic Maps of the guinea pig as well as an aid for genome assembly assignment to specific Chromosomes. Furthermore, the comparative Mapping will allow a transfer of gene Map data from other species. The probes developed here provide a genomic toolkit, which will make the guinea pig a key species to unravel the evolutionary biology of the Hystricomorph rodents.

  • phylogenomics of the dog and fox family canidae carnivora revealed by Chromosome painting
    Chromosome Research, 2008
    Co-Authors: Alexander S. Graphodatsky, Polina L Perelman, Natalya V Sokolovskaya, Violetta R Beklemisheva, Natalya A Serdukova, Gauthier Dobigny, Malcolm A Fergusonsmith, Stephen J Obrien, Fengtang Yang
    Abstract:

    Canid species (dogs and foxes) have highly rearranged karyotypes and thus represent a challenge for conventional comparative cytogenetic studies. Among them, the domestic dog is one of the best-Mapped species in mammals, constituting an ideal reference genome for comparative genomic study. Here we report the results of genomewide comparative Mapping of dog Chromosome-specific probes onto Chromosomes of the dhole, fennec fox, and gray fox, as well as the Mapping of red fox Chromosome-specific probes onto Chromosomes of the corsac fox. We also present an integrated comparative Chromosome Map between the species studied here and all canids studied previously. The integrated Map demonstrates an extensive conservation of whole Chromosome arms across different canid species. In addition, we have generated a comprehensive genome phylogeny for the Canidae on the basis of the Chromosome rearrangements revealed by comparative painting. This genome phylogeny has provided new insights into the karyotypic relationships among the canids. Our results, together with published data, allow the formulation of a likely Canidae ancestral karyotype (CAK, 2n = 82), and reveal that at least 6Y24 chromosomal fission/fusion events are needed to convert the CAK karyotype to that of the modern canids.

  • chromosomal evolution of arvicolinae cricetidae rodentia ii the genome homology of two mole voles genus ellobius the field vole and golden hamster revealed by comparative Chromosome painting
    Chromosome Research, 2007
    Co-Authors: Svetlana A Romanenko, Irina Bakloushinskaya, Polina L Perelman, Natalya A Serdukova, Malcolm A Fergusonsmith, Natalia A Sitnikova, Nadezhda V Rubtsova, Elena A Lyapunova, Walter Just, Fengtang Yang
    Abstract:

    Using cross-species Chromosome painting, we have carried out a comprehensive comparison of the karyotypes of two Ellobius species with unusual sex determination systems: the Transcaucasian mole vole, Ellobius lutescens (2n = 17, X in both sexes), and the northern mole vole, Ellobius talpinus (2n = 54, XX in both sexes). Both Ellobius species have highly rearranged karyotypes. The chromosomal paints from the field vole (Microtus agrestis) detected, in total, 34 and 32 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. No difference in hybridization pattern of the X paint (as well as Y paint) probes on male and female Chromosomes was discovered. The set of golden hamster (Mesocricetus auratus) chromosomal painting probes revealed 44 and 43 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. A comparative Chromosome Map was established based on the results of cross-species Chromosome painting and a hypothetical ancestral Ellobius karyotype was reconstructed. A considerable number of rearrangements were detected; 31 and 7 fusion/fission rearrangements differentiated the karyotypes of E. lutescens and E. talpinus from the ancestral Ellobius karyotype. It seems that inversions have played a minor role in the genome evolution of these Ellobius species.

  • cross species Chromosome painting among camel cattle pig and human further insights into the putative cetartiodactyla ancestral karyotype
    Chromosome Research, 2007
    Co-Authors: Gabriel Balmus, Alexander S. Graphodatsky, Vladimir A Trifonov, Larisa S Biltueva, Patricia C M Obrien, Elena S Alkalaeva, Beiyuan Fu, Julian A Skidmore, Twink Allen, Fengtang Yang
    Abstract:

    The great karyotypic differences between camel, cattle and pig, three important domestic animals, have been a challenge for comparative cytogenetic studies based on conventional cytogenetic approaches. To construct a genome-wide comparative Chromosome Map among these artiodactyls, we made a set of Chromosome painting probes from the dromedary camel (Camelus dromedarius) by flow sorting and degenerate oligonucleotide primed-PCR. The painting probes were first used to characterize the karyotypes of the dromedary camel (C. dromedarius), the Bactrian camel (C. bactrianus), the guanaco (Lama guanicoe), the alpaca (L. pacos) and dromedary × guanaco hybrid karyotypes (all with 2n = 74). These FISH experiments enabled the establishment of a high-resolution GTG-banded karyotype, together with Chromosome nomenclature and idiogram for C. dromedarius, and revealed that these camelid species have almost identical karyotypes, with only slight variations in the amount and distribution patterns of heterochromatin. Further cross-species Chromosome painting between camel, cattle, pig and human with painting probes from the camel and human led to the establishment of genome-wide comparative Maps. Between human and camel, pig and camel, and cattle and camel 47, 53 and 53 autosomal conserved segments were detected, respectively. Integrated analysis with previously published comparative Maps of human/pig/cattle enabled us to propose a Cetartiodactyla ancestral karyotype and to discuss the early karyotype evolution of Cetartiodactyla. Furthermore, these Maps will facilitate the positional cloning of genes by aiding the cross-species transfer of Mapping information.

  • chromosomal evolution of arvicolinae cricetidae rodentia i the genome homology of tundra vole field vole mouse and golden hamster revealed by comparative Chromosome painting
    Chromosome Research, 2007
    Co-Authors: Natalia A Sitnikova, Polina L Perelman, Natalya A Serdukova, Malcolm A Fergusonsmith, Svetlana A Romanenko, Vladimir A Trifonov, Patricia C M Obrien, Nadezhda V Rubtsova, F N Golenishchev, Fengtang Yang
    Abstract:

    Cross-species Chromosome painting has become the mainstay of comparative cytogenetic and Chromosome evolution studies. Here we have made a set of chromosomal painting probes for the field vole (Microtus agrestis) by DOP-PCR amplification of flow-sorted Chromosomes. Together with painting probes of golden hamster (Mesocricetus auratus) and mouse (Mus musculus), the field vole probes have been hybridized onto the metaphases of the tundra vole (Microtus oeconomus). A comparative Chromosome Map between these two voles, golden hamster and mouse has been established based on the results of cross-species Chromosome painting and G-banding comparisons. The sets of paints from the field vole, golden hamster and mouse identified a total of 27, 40 and 47 homologous autosomal regions, respectively, in the genome of tundra vole; 16, 41 and 51 fusion/fission rearrangements differentiate the karyotype of the tundra vole from the karyotypes of the field vole, golden hamster and mouse, respectively.

A P Milone - One of the best experts on this subject based on the ideXlab platform.

  • a Chromosome Map to unveil stellar populations with different magnesium abundances the case of ω centauri
    Monthly Notices of the Royal Astronomical Society, 2020
    Co-Authors: A P Milone, A F Marino, A Renzini, Giada Cordoni, S Jang, E P Lagioia, M Tailo, Marilia Carlos, E Dondoglio
    Abstract:

    Historically, photometry has been largely used to identify stellar populations (MPs) in Globular Clusters (GCs) by using diagrams that are based on colours and magnitudes that are mostly sensitive to stars with different metallicities or different abundances of helium, carbon, nitrogen and oxygen. In particular, the pseudo two-colour diagram called Chromosome Map (ChM), allowed the identification and the characterization of MPs in about 70 GCs by using appropriate filters of the Hubble Space Telescope (HST) that are sensitive to the stellar content of He, C, N, O and Fe. We use here high-precision HST photometry from F275W, F280N, F343N, F373N, and F814W images of Omega Centauri to investigate its MPs. We introduce a new ChM whose abscissa and ordinate are mostly sensitive to stellar populations with different magnesium and nitrogen, respectively, in monometallic GCs. This ChM is effective in disentangling the MPs based on their Mg chemical abundances, allowing us to explore, for the first time, possible relations between the production of these elemental species for large samples of stars in GCs. By comparing the colours of the distinct stellar populations with the colours obtained from appropriate synthetic spectra we provide 'photometric-like' estimates of the chemical composition of each population. Our results show that, in addition to first generation (1G) stars, the metal-poor population of Omega Centauri hosts four groups of second-generation stars with different [N/Fe], namely, 2GA--D. 2GA stars share nearly the same [Mg/Fe] as the 1G, whereas 2GB, 2GC and 2GD stars are Mg depleted by ~0.15, ~0.25 and ~0.45 dex, respectively. We provide evidence that the metal-intermediate populations host stars with depleted [Mg/Fe].

  • chemical abundances along the 1g sequence of the Chromosome Maps the globular cluster ngc 3201
    arXiv: Solar and Stellar Astrophysics, 2019
    Co-Authors: A F Marino, A P Milone, A Renzini, L R Bedin, Giada Cordoni, Francesca Dantona, Helmut Jerjen, David Yong, Alison Sills, Amanda I Karakas
    Abstract:

    The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated multiple stellar populations by means of the "Chromosome Map" (ChM) diagnostic tool that maximises the separation between stars with different chemical composition. One of the most challenging features revealed by ChMs analysis is the apparent inhomogeneity among stars belonging to the first population, a phenomenon largely attributed to He variations. However, this explanation is not supported by the uniformity in p-capture elements of these stars. The HST survey has revealed that the GC NGC 3201 shows an exceptionally wide coverage in the Delta(F275W,F814W) parameter of the ChM. We present a chemical abundance analysis of 24 elements in 18 giants belonging to the first population of this GC, and having a wide range in Delta(F275W,F814W). As far as the p-capture elements are concerned, the chemical abundances are typical of 1G stars, as expected from the location of our targets in the ChM. Based on radial velocities and chemical abundances arguments, we find that the three stars with the lowest Delta(F275W,F814W) values are binary candidates. This suggests that, at least those stars could be explained with binarity. These results are consistent with evidence inferred from multi-band photometry that evolved blue stragglers populate the bluest part of the 1G sequence in the ChM. The remaining 15 spectroscopic targets show a small range in the overall metallicity by ~0.10 dex, with stars at higher Delta(F275W,F814W) values having higher absolute abundances. We suggest that a small variation in metals and binarity govern the color spread of the 1G in the ChM, and that evolved blue stragglers contribute to the bluest tail of the 1G sequence.

  • the hubble space telescope uv legacy survey of galactic globular clusters xix a chemical tagging of the multiple stellar populations over the Chromosome Maps
    Monthly Notices of the Royal Astronomical Society, 2019
    Co-Authors: A F Marino, A P Milone, A Renzini, L R Bedin, Giada Cordoni, Francesca Dantona, E P Lagioia, Jay Anderson, A Bellini, G Piotto
    Abstract:

    The HST UV Survey of Globular Clusters (GCs) has investigated GCs and their stellar populations. In previous papers of this series we have introduced a pseudo two-color diagram, "Chromosome Map" (ChM), that maximises the separation between the multiple populations. We have identified two main classes of GCs: Type I (~83% of the objects) and Type II, both hosting two main groups of stars, referred to in this series as first (1G) and second generation (2G). Type II clusters exhibit two or more parallel sequences of 1G and 2G stars in their ChMs. We exploit elemental abundances from literature to assign the chemical composition to the distinct populations as identified on the ChMs of 29 GCs. We find that stars in different regions of the ChM have different composition: 1G stars share the same light-element content as field stars, while 2G stars are enhanced in N, Na and depleted in O. Stars enhanced in Al and depleted in Mg populate the extreme regions of the ChM. We investigate the color spread among 1G stars observed in many GCs, and find no evidence for variations in light elements, whereas either a 0.1 dex Fe spread or a variation in He remain to be verified. In the attempt of analysing the global properties of the multiple populations, we have constructed a universal ChM, which highlights that, though variegate, the phenomenon has some common pattern. The universal ChM reveals a tight connection with Na, for which we have provided an empirical relation. The additional ChM sequences typical of Type II GCs are enhanced in metallicity and, often, in s elements. Omega Cen can be classified as an extreme Type II GC, with a ChM displaying three main streams, each with its own variations in chemical abundances. One of the most noticeable differences is between the lower and upper streams, with the latter (associated with higher He) having higher Fe and lower Li. We publicly release ChMs.

  • the hubble space telescope uv legacy survey of galactic globular clusters ix the atlas of multiple stellar populations
    Monthly Notices of the Royal Astronomical Society, 2017
    Co-Authors: A P Milone, A F Marino, A Renzini, L R Bedin, Francesca Dantona, G Piotto, Enrico Vesperini, D Nardiello, Jay Anderson, Ivan R King
    Abstract:

    We use high-precision photometry of red-giant-branch (RGB) stars in 57 Galactic globular clusters (GCs), mostly from the 'Hubble Space Telescope (HST ) UV Legacy Survey of Galactic GCs', to identify and characterize their multiple stellar populations. For each cluster the pseudo-two-colour diagram (or 'Chromosome Map') is presented, built with a suitable combination of stellar magnitudes in the F275W, F336W, F438W, and F814W filters that maximizes the separation between multiple populations. In the Chromosome Map of most GCs (type-I clusters), stars separate in two distinct groups that we identify with the first (1G) and the second generation (2G). This identification is further supported by noticing that 1G stars have primordial (oxygen-rich, sodium-poor) chemical composition, whereas 2G stars are enhanced in sodium and depleted in oxygen. This 1G-2G separation is not possible for a few GCs where the two sequences have apparently merged into an extended, continuous sequence. In some GCs (type-II clusters) the 1G and/or the 2G sequences appear to be split, hence displaying more complex Chromosome Maps. These clusters exhibit multiple subgiant branches (SGBs) also in purely optical colour-magnitude diagrams, with the fainter SGB joining into a red RGB which is populated by stars with enhanced heavy-element abundance. We measure the RGB width by using appropriate colours and pseudo-colours. When the metallicity dependence is removed, the RGB width correlates with the cluster mass. The fraction of 1G stars ranges from ~8 per cent to ~67 per cent and anticorrelates with the cluster mass, indicating that incidence and complexity of the multiple population phenomenon both increase with cluster mass.

A F Marino - One of the best experts on this subject based on the ideXlab platform.

  • a Chromosome Map to unveil stellar populations with different magnesium abundances the case of ω centauri
    Monthly Notices of the Royal Astronomical Society, 2020
    Co-Authors: A P Milone, A F Marino, A Renzini, Giada Cordoni, S Jang, E P Lagioia, M Tailo, Marilia Carlos, E Dondoglio
    Abstract:

    Historically, photometry has been largely used to identify stellar populations (MPs) in Globular Clusters (GCs) by using diagrams that are based on colours and magnitudes that are mostly sensitive to stars with different metallicities or different abundances of helium, carbon, nitrogen and oxygen. In particular, the pseudo two-colour diagram called Chromosome Map (ChM), allowed the identification and the characterization of MPs in about 70 GCs by using appropriate filters of the Hubble Space Telescope (HST) that are sensitive to the stellar content of He, C, N, O and Fe. We use here high-precision HST photometry from F275W, F280N, F343N, F373N, and F814W images of Omega Centauri to investigate its MPs. We introduce a new ChM whose abscissa and ordinate are mostly sensitive to stellar populations with different magnesium and nitrogen, respectively, in monometallic GCs. This ChM is effective in disentangling the MPs based on their Mg chemical abundances, allowing us to explore, for the first time, possible relations between the production of these elemental species for large samples of stars in GCs. By comparing the colours of the distinct stellar populations with the colours obtained from appropriate synthetic spectra we provide 'photometric-like' estimates of the chemical composition of each population. Our results show that, in addition to first generation (1G) stars, the metal-poor population of Omega Centauri hosts four groups of second-generation stars with different [N/Fe], namely, 2GA--D. 2GA stars share nearly the same [Mg/Fe] as the 1G, whereas 2GB, 2GC and 2GD stars are Mg depleted by ~0.15, ~0.25 and ~0.45 dex, respectively. We provide evidence that the metal-intermediate populations host stars with depleted [Mg/Fe].

  • chemical abundances along the 1g sequence of the Chromosome Maps the globular cluster ngc 3201
    arXiv: Solar and Stellar Astrophysics, 2019
    Co-Authors: A F Marino, A P Milone, A Renzini, L R Bedin, Giada Cordoni, Francesca Dantona, Helmut Jerjen, David Yong, Alison Sills, Amanda I Karakas
    Abstract:

    The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated multiple stellar populations by means of the "Chromosome Map" (ChM) diagnostic tool that maximises the separation between stars with different chemical composition. One of the most challenging features revealed by ChMs analysis is the apparent inhomogeneity among stars belonging to the first population, a phenomenon largely attributed to He variations. However, this explanation is not supported by the uniformity in p-capture elements of these stars. The HST survey has revealed that the GC NGC 3201 shows an exceptionally wide coverage in the Delta(F275W,F814W) parameter of the ChM. We present a chemical abundance analysis of 24 elements in 18 giants belonging to the first population of this GC, and having a wide range in Delta(F275W,F814W). As far as the p-capture elements are concerned, the chemical abundances are typical of 1G stars, as expected from the location of our targets in the ChM. Based on radial velocities and chemical abundances arguments, we find that the three stars with the lowest Delta(F275W,F814W) values are binary candidates. This suggests that, at least those stars could be explained with binarity. These results are consistent with evidence inferred from multi-band photometry that evolved blue stragglers populate the bluest part of the 1G sequence in the ChM. The remaining 15 spectroscopic targets show a small range in the overall metallicity by ~0.10 dex, with stars at higher Delta(F275W,F814W) values having higher absolute abundances. We suggest that a small variation in metals and binarity govern the color spread of the 1G in the ChM, and that evolved blue stragglers contribute to the bluest tail of the 1G sequence.

  • the hubble space telescope uv legacy survey of galactic globular clusters xix a chemical tagging of the multiple stellar populations over the Chromosome Maps
    Monthly Notices of the Royal Astronomical Society, 2019
    Co-Authors: A F Marino, A P Milone, A Renzini, L R Bedin, Giada Cordoni, Francesca Dantona, E P Lagioia, Jay Anderson, A Bellini, G Piotto
    Abstract:

    The HST UV Survey of Globular Clusters (GCs) has investigated GCs and their stellar populations. In previous papers of this series we have introduced a pseudo two-color diagram, "Chromosome Map" (ChM), that maximises the separation between the multiple populations. We have identified two main classes of GCs: Type I (~83% of the objects) and Type II, both hosting two main groups of stars, referred to in this series as first (1G) and second generation (2G). Type II clusters exhibit two or more parallel sequences of 1G and 2G stars in their ChMs. We exploit elemental abundances from literature to assign the chemical composition to the distinct populations as identified on the ChMs of 29 GCs. We find that stars in different regions of the ChM have different composition: 1G stars share the same light-element content as field stars, while 2G stars are enhanced in N, Na and depleted in O. Stars enhanced in Al and depleted in Mg populate the extreme regions of the ChM. We investigate the color spread among 1G stars observed in many GCs, and find no evidence for variations in light elements, whereas either a 0.1 dex Fe spread or a variation in He remain to be verified. In the attempt of analysing the global properties of the multiple populations, we have constructed a universal ChM, which highlights that, though variegate, the phenomenon has some common pattern. The universal ChM reveals a tight connection with Na, for which we have provided an empirical relation. The additional ChM sequences typical of Type II GCs are enhanced in metallicity and, often, in s elements. Omega Cen can be classified as an extreme Type II GC, with a ChM displaying three main streams, each with its own variations in chemical abundances. One of the most noticeable differences is between the lower and upper streams, with the latter (associated with higher He) having higher Fe and lower Li. We publicly release ChMs.

  • the hubble space telescope uv legacy survey of galactic globular clusters ix the atlas of multiple stellar populations
    Monthly Notices of the Royal Astronomical Society, 2017
    Co-Authors: A P Milone, A F Marino, A Renzini, L R Bedin, Francesca Dantona, G Piotto, Enrico Vesperini, D Nardiello, Jay Anderson, Ivan R King
    Abstract:

    We use high-precision photometry of red-giant-branch (RGB) stars in 57 Galactic globular clusters (GCs), mostly from the 'Hubble Space Telescope (HST ) UV Legacy Survey of Galactic GCs', to identify and characterize their multiple stellar populations. For each cluster the pseudo-two-colour diagram (or 'Chromosome Map') is presented, built with a suitable combination of stellar magnitudes in the F275W, F336W, F438W, and F814W filters that maximizes the separation between multiple populations. In the Chromosome Map of most GCs (type-I clusters), stars separate in two distinct groups that we identify with the first (1G) and the second generation (2G). This identification is further supported by noticing that 1G stars have primordial (oxygen-rich, sodium-poor) chemical composition, whereas 2G stars are enhanced in sodium and depleted in oxygen. This 1G-2G separation is not possible for a few GCs where the two sequences have apparently merged into an extended, continuous sequence. In some GCs (type-II clusters) the 1G and/or the 2G sequences appear to be split, hence displaying more complex Chromosome Maps. These clusters exhibit multiple subgiant branches (SGBs) also in purely optical colour-magnitude diagrams, with the fainter SGB joining into a red RGB which is populated by stars with enhanced heavy-element abundance. We measure the RGB width by using appropriate colours and pseudo-colours. When the metallicity dependence is removed, the RGB width correlates with the cluster mass. The fraction of 1G stars ranges from ~8 per cent to ~67 per cent and anticorrelates with the cluster mass, indicating that incidence and complexity of the multiple population phenomenon both increase with cluster mass.