The Experts below are selected from a list of 7050 Experts worldwide ranked by ideXlab platform
Marilyn B Renfree - One of the best experts on this subject based on the ideXlab platform.
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development of the penile urethra in the tammar Wallaby
Sexual Development, 2011Co-Authors: Michael W Leihy, Geoff Shaw, Jean D Wilson, Marilyn B RenfreeAbstract:Hypospadias is increasingly common, and requires surgery to repair, but its aetiology is poorly understood. The marsupial tammar Wallaby provides a unique opportunity to study hypospadias because peni
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transcriptomic analysis supports similar functional roles for the two thymuses of the tammar Wallaby
BMC Genomics, 2011Co-Authors: Emily S W Wong, Anthony T Papenfuss, Andreas Heger, Arthur Hsu, Chris P Ponting, Robert D Miller, Jane C Fenelon, Marilyn B Renfree, Richard A Gibbs, Katherine BelovAbstract:Background The thymus plays a critical role in the development and maturation of T-cells. Humans have a single thoracic thymus and presence of a second thymus is considered an anomaly. However, many vertebrates have multiple thymuses. The tammar Wallaby has two thymuses: a thoracic thymus (typically found in all mammals) and a dominant cervical thymus. Researchers have known about the presence of the two Wallaby thymuses since the 1800s, but no genome-wide research has been carried out into possible functional differences between the two thymic tissues. Here, we used pyrosequencing to compare the transcriptomes of a cervical and thoracic thymus from a single 178 day old tammar Wallaby.
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Reproduction in female swamp wallabies, Wallabia bicolor
Reproduction fertility and development, 2006Co-Authors: Justyna Zofia Paplinska, Richard L. C. Moyle, Peter Temple-smith, Marilyn B RenfreeAbstract:The swamp Wallaby (Wallabia bicolor) is a common, medium-sized, browsing macropodid marsupial that is unique in many ways. Relatively little is known about the reproductive biology of this species. Previous studies have proposed that the swamp Wallaby has a pre-partum oestrus because the gestation period (x = 35.5 days, n = 4) is on average longer than the oestrus period (x = 31.0 days, n = 5) and the period from the removal of pouch young (RPY) to mating (x = 26.0 days, n = 3). In the current study, the period from RPY to birth was confirmed at x = 31.25 days (n = 4) in captive animals, consistent with a pre-partum oestrus. A growth curve for swamp Wallaby pouch young was constructed from the progeny of captive animals to estimate the age and date of birth of young in a wild, culled population in South Gippsland, Victoria, and the reproduction of females in the wild throughout the year was examined. Young were born in every month of the year, with no statistically significant variation in the number of young born in each month. Females did not have a period of seasonal anoestrus and conceived throughout the year. Female swamp wallabies in South Gippsland bred continuously throughout the period of this study.
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maternal regulation of milk composition milk production and pouch young development during lactation in the tammar Wallaby macropus eugenii
Biology of Reproduction, 2003Co-Authors: Josephine F Trott, Kevin R. Nicholas, Richard L. C. Moyle, Kaylene J Simpson, Cyrma M Hearn, Geoffrey Shaw, Marilyn B RenfreeAbstract:Specific changes in milk composition during lactation in the tammar Wallaby (Macropus eugenii) were correlated with the ages of the developing pouch young (PY). The present experiment was designed to test the hypothesis that the sucking pattern of the PY determines the course of mammary development in the tammar Wallaby. To test this hypothesis, groups of 60-day-old PY were fostered repeatedly onto one group of host mothers so that a constant sucking stimulus on the mammary gland was maintained for 56 days to allow the lactational stage to progress 42 days ahead of the age of the young. Analysis of the milk in fostered and control groups showed the timing of changes in the concentration of protein and carbohydrate were essentially unaffected by altering the sucking regime. The only change in milk protein secretion was a small delay in the timing of down-regulation of the secretion of whey acidic protein and early lactation protein in the host tammars. In addition, the rates of growth and development of the foster PY were significantly increased relative to those of the control PY because of ingesting more milk with a higher energy content and different composition than normal for their age. The present study demonstrates that the lactating tammar Wallaby regulates both milk composition and the rate of milk production and that these determine the rates of PY growth and development, irrespective of the age of the PY.
Katherine Belov - One of the best experts on this subject based on the ideXlab platform.
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molecular characterisation of interleukin 2 in two australian marsupials the tammar Wallaby notamacropus eugenii and the tasmanian devil sarcophilus harrisii facilitates the development of marsupial specific immunological reagents
Australian Mammalogy, 2018Co-Authors: Lauren J. Young, Jessica Gurr, Katrina M Morris, Sabine Flenady, Katherine BelovAbstract:Interleukin-2 (IL-2) is an important regulator of cellular immunity in mammals. For many years, our inability to identify the expression of this cytokine in marsupials hindered our capacity to progress studies in metatherian immunology. Here, we report the use of molecular techniques to characterise the IL-2 gene for the tammar Wallaby (Notamacropus eugenii) and the Tasmanian devil (Sarcophilus harrisii), which allowed the prediction of the structure and probable functions of the IL-2 proteins of these species. Deduced marsupial IL-2 proteins show considerable sequence identity to each other and to common brushtail possum (Trichosurus vulpecula) IL-2 (≥65%) but shared only 35% (tammar Wallaby) and 32% (Tasmanian devil) identity with human IL-2. This difference means that reagents used to study IL-2 in human and other eutherians are unlikely to cross-react with marsupials. As a key step in furthering our ability to study cellular immune responses in marsupials and, more specifically, the susceptibility of macropodoid marsupials to intracellular pathogens, a polyclonal antibody was designed for the detection and future investigation of tammar Wallaby IL-2 protein expression. The molecular data and polyclonal antibody described herein will support our development of gene probes and immunological reagents that will aid studies of infection and disease in marsupials.
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A first-generation integrated tammar Wallaby map and its use in creating a tammar Wallaby first-generation virtual genome map
BMC Genomics, 2011Co-Authors: Chenwei Wang, Janine E. Deakin, Willem Rens, Kyall R. Zenger, Katherine Belov, Jennifer A. Marshall Graves, Frank W. NicholasAbstract:The limited (2X) coverage of the tammar Wallaby (Macropus eugenii) genome sequence dataset currently presents a challenge for assembly and anchoring onto chromosomes. To provide a framework for this assembly, it would be a great advantage to have a dense map of the tammar Wallaby genome. However, only limited mapping data are available for this non-model species, comprising a physical map and a linkage map. We combined all available tammar Wallaby mapping data to create a tammar Wallaby integrated map, using the Location DataBase (LDB) strategy. This first-generation integrated map combines all available information from the second-generation tammar Wallaby linkage map with 148 loci, and extensive FISH mapping data for 492 loci, especially for genes likely to be located at the ends of Wallaby chromosomes or at evolutionary breakpoints inferred from comparative information. For loci whose positions are only approximately known, their location in the integrated map was refined on the basis of comparative information from opossum (Monodelphis domestica) and human. Interpolation of segments from the opossum and human assemblies into the integrated map enabled the subsequent construction of a tammar Wallaby first-generation virtual genome map, which comprises 14336 markers, including 13783 genes recruited from opossum and human assemblies. Both maps are freely available at http://compldb.angis.org.au . The first-generation integrated map and the first-generation virtual genome map provide a backbone for the chromosome assembly of the tammar Wallaby genome sequence. For example, 78% of the 10257 gene-scaffolds in the Ensembl annotation of the tammar Wallaby genome sequence (including 10522 protein-coding genes) can now be given a chromosome location in the tammar Wallaby virtual genome map.
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a first generation integrated tammar Wallaby map and its use in creating a tammar Wallaby first generation virtual genome map
BMC Genomics, 2011Co-Authors: Janine E. Deakin, Chenwei Wang, Willem Rens, Kyall R. Zenger, Katherine Belov, Jennifer Marshall A GravesAbstract:Background: The limited (2X) coverage of the tammar Wallaby (Macropus eugenii) genome sequence dataset currently presents a challenge for assembly and anchoring onto chromosomes. To provide a framework for this assembly, it would be a great advantage to have a dense map of the tammar Wallaby genome. However, only limited mapping data are available for this non-model species, comprising a physical map and a linkage map. Results: We combined all available tammar Wallaby mapping data to create a tammar Wallaby integrated map, using the Location DataBase (LDB) strategy. This first-generation integrated map combines all available information from the second-generation tammar Wallaby linkage map with 148 loci, and extensive FISH mapping data for 492 loci, especially for genes likely to be located at the ends of Wallaby chromosomes or at evolutionary breakpoints inferred from comparative information. For loci whose positions are only approximately known, their location in the integrated map was refined on the basis of comparative information from opossum (Monodelphis domestica) and human. Interpolation of segments from the opossum and human assemblies into the integrated map enabled the subsequent construction of a tammar Wallaby first-generation virtual genome map, which comprises 14336 markers, including 13783 genes recruited from opossum and human assemblies. Both maps are freely available at http://compldb.angis.org.au. Conclusions: The first-generation integrated map and the first-generation virtual genome map provide a backbone for the chromosome assembly of the tammar Wallaby genome sequence. For example, 78% of the 10257 genescaffolds in the Ensembl annotation of the tammar Wallaby genome sequence (including 10522 protein-coding genes) can now be given a chromosome location in the tammar Wallaby virtual genome map.
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the tammar Wallaby major histocompatibility complex shows evidence of past genomic instability
BMC Genomics, 2011Co-Authors: Hannah V Siddle, Janine E. Deakin, Penny Coggill, Laurens G Whilming, Jennifer Harrow, James C Kaufman, Stephan Beck, Katherine BelovAbstract:Background: The major histocompatibility complex (MHC) is a group of genes with a variety of roles in the innate and adaptive immune responses. MHC genes form a genetically linked cluster in eutherian mammals, an organization that is thought to confer functional and evolutionary advantages to the immune system. The tammar Wallaby (Macropus eugenii), an Australian marsupial, provides a unique model for understanding MHC gene evolution, as many of its antigen presenting genes are not linked to the MHC, but are scattered around the genome. Results: Here we describe the ‘core’ tammar Wallaby MHC region on chromosome 2q by ordering and sequencing 33 BAC clones, covering over 4.5 MB and containing 129 genes. When compared to the MHC region of the South American opossum, eutherian mammals and non-mammals, the Wallaby MHC has a novel gene organization. The Wallaby has undergone an expansion of MHC class II genes, which are separated into two clusters by the class III genes. The antigen processing genes have undergone duplication, resulting in two copies of TAP1 and three copies of TAP2. Notably, Kangaroo Endogenous Retroviral Elements are present within the region and may have contributed to the genomic instability. Conclusions: The Wallaby MHC has been extensively remodeled since the American and Australian marsupials last shared a common ancestor. The instability is characterized by the movement of antigen presenting genes away from the core MHC, most likely via the presence and activity of retroviral elements. We propose that the movement of class II genes away from the ancestral class II region has allowed this gene family to expand and diversify in the Wallaby. The duplication of TAP genes in the Wallaby MHC makes this species a unique model organism for studying the relationship between MHC gene organization and function.
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transcriptomic analysis supports similar functional roles for the two thymuses of the tammar Wallaby
BMC Genomics, 2011Co-Authors: Emily S W Wong, Anthony T Papenfuss, Andreas Heger, Arthur Hsu, Chris P Ponting, Robert D Miller, Jane C Fenelon, Marilyn B Renfree, Richard A Gibbs, Katherine BelovAbstract:Background The thymus plays a critical role in the development and maturation of T-cells. Humans have a single thoracic thymus and presence of a second thymus is considered an anomaly. However, many vertebrates have multiple thymuses. The tammar Wallaby has two thymuses: a thoracic thymus (typically found in all mammals) and a dominant cervical thymus. Researchers have known about the presence of the two Wallaby thymuses since the 1800s, but no genome-wide research has been carried out into possible functional differences between the two thymic tissues. Here, we used pyrosequencing to compare the transcriptomes of a cervical and thoracic thymus from a single 178 day old tammar Wallaby.
Janine E. Deakin - One of the best experts on this subject based on the ideXlab platform.
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A first-generation integrated tammar Wallaby map and its use in creating a tammar Wallaby first-generation virtual genome map
BMC Genomics, 2011Co-Authors: Chenwei Wang, Janine E. Deakin, Willem Rens, Kyall R. Zenger, Katherine Belov, Jennifer A. Marshall Graves, Frank W. NicholasAbstract:The limited (2X) coverage of the tammar Wallaby (Macropus eugenii) genome sequence dataset currently presents a challenge for assembly and anchoring onto chromosomes. To provide a framework for this assembly, it would be a great advantage to have a dense map of the tammar Wallaby genome. However, only limited mapping data are available for this non-model species, comprising a physical map and a linkage map. We combined all available tammar Wallaby mapping data to create a tammar Wallaby integrated map, using the Location DataBase (LDB) strategy. This first-generation integrated map combines all available information from the second-generation tammar Wallaby linkage map with 148 loci, and extensive FISH mapping data for 492 loci, especially for genes likely to be located at the ends of Wallaby chromosomes or at evolutionary breakpoints inferred from comparative information. For loci whose positions are only approximately known, their location in the integrated map was refined on the basis of comparative information from opossum (Monodelphis domestica) and human. Interpolation of segments from the opossum and human assemblies into the integrated map enabled the subsequent construction of a tammar Wallaby first-generation virtual genome map, which comprises 14336 markers, including 13783 genes recruited from opossum and human assemblies. Both maps are freely available at http://compldb.angis.org.au . The first-generation integrated map and the first-generation virtual genome map provide a backbone for the chromosome assembly of the tammar Wallaby genome sequence. For example, 78% of the 10257 gene-scaffolds in the Ensembl annotation of the tammar Wallaby genome sequence (including 10522 protein-coding genes) can now be given a chromosome location in the tammar Wallaby virtual genome map.
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a first generation integrated tammar Wallaby map and its use in creating a tammar Wallaby first generation virtual genome map
BMC Genomics, 2011Co-Authors: Janine E. Deakin, Chenwei Wang, Willem Rens, Kyall R. Zenger, Katherine Belov, Jennifer Marshall A GravesAbstract:Background: The limited (2X) coverage of the tammar Wallaby (Macropus eugenii) genome sequence dataset currently presents a challenge for assembly and anchoring onto chromosomes. To provide a framework for this assembly, it would be a great advantage to have a dense map of the tammar Wallaby genome. However, only limited mapping data are available for this non-model species, comprising a physical map and a linkage map. Results: We combined all available tammar Wallaby mapping data to create a tammar Wallaby integrated map, using the Location DataBase (LDB) strategy. This first-generation integrated map combines all available information from the second-generation tammar Wallaby linkage map with 148 loci, and extensive FISH mapping data for 492 loci, especially for genes likely to be located at the ends of Wallaby chromosomes or at evolutionary breakpoints inferred from comparative information. For loci whose positions are only approximately known, their location in the integrated map was refined on the basis of comparative information from opossum (Monodelphis domestica) and human. Interpolation of segments from the opossum and human assemblies into the integrated map enabled the subsequent construction of a tammar Wallaby first-generation virtual genome map, which comprises 14336 markers, including 13783 genes recruited from opossum and human assemblies. Both maps are freely available at http://compldb.angis.org.au. Conclusions: The first-generation integrated map and the first-generation virtual genome map provide a backbone for the chromosome assembly of the tammar Wallaby genome sequence. For example, 78% of the 10257 genescaffolds in the Ensembl annotation of the tammar Wallaby genome sequence (including 10522 protein-coding genes) can now be given a chromosome location in the tammar Wallaby virtual genome map.
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A second-generation anchored genetic linkage map of the tammar Wallaby (Macropus eugenii)
BMC genetics, 2011Co-Authors: Chenwei Wang, Janine E. Deakin, Jennifer A. Marshall Graves, Lee Webley, Ke-jun Wei, Matthew J. Wakefield, Hardip R. Patel, Amber E. Alsop, Desmond W. Cooper, Frank W. NicholasAbstract:The tammar Wallaby, Macropus eugenii, a small kangaroo used for decades for studies of reproduction and metabolism, is the model Australian marsupial for genome sequencing and genetic investigations. The production of a more comprehensive cytogenetically-anchored genetic linkage map will significantly contribute to the deciphering of the tammar Wallaby genome. It has great value as a resource to identify novel genes and for comparative studies, and is vital for the ongoing genome sequence assembly and gene ordering in this species. A second-generation anchored tammar Wallaby genetic linkage map has been constructed based on a total of 148 loci. The linkage map contains the original 64 loci included in the first-generation map, plus an additional 84 microsatellite loci that were chosen specifically to increase coverage and assist with the anchoring and orientation of linkage groups to chromosomes. These additional loci were derived from (a) sequenced BAC clones that had been previously mapped to tammar Wallaby chromosomes by fluorescence in situ hybridization (FISH), (b) End sequence from BACs subsequently FISH-mapped to tammar Wallaby chromosomes, and (c) tammar Wallaby genes orthologous to opossum genes predicted to fill gaps in the tammar Wallaby linkage map as well as three X-linked markers from a published study. Based on these 148 loci, eight linkage groups were formed. These linkage groups were assigned (via FISH-mapped markers) to all seven autosomes and the X chromosome. The sex-pooled map size is 1402.4 cM, which is estimated to provide 82.6% total coverage of the genome, with an average interval distance of 10.9 cM between adjacent markers. The overall ratio of female/male map length is 0.84, which is comparable to the ratio of 0.78 obtained for the first-generation map. Construction of this second-generation genetic linkage map is a significant step towards complete coverage of the tammar Wallaby genome and considerably extends that of the first-generation map. It will be a valuable resource for ongoing tammar Wallaby genetic research and assembling the genome sequence. The sex-pooled map is available online at http://compldb.angis.org.au/.
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the tammar Wallaby major histocompatibility complex shows evidence of past genomic instability
BMC Genomics, 2011Co-Authors: Hannah V Siddle, Janine E. Deakin, Penny Coggill, Laurens G Whilming, Jennifer Harrow, James C Kaufman, Stephan Beck, Katherine BelovAbstract:Background: The major histocompatibility complex (MHC) is a group of genes with a variety of roles in the innate and adaptive immune responses. MHC genes form a genetically linked cluster in eutherian mammals, an organization that is thought to confer functional and evolutionary advantages to the immune system. The tammar Wallaby (Macropus eugenii), an Australian marsupial, provides a unique model for understanding MHC gene evolution, as many of its antigen presenting genes are not linked to the MHC, but are scattered around the genome. Results: Here we describe the ‘core’ tammar Wallaby MHC region on chromosome 2q by ordering and sequencing 33 BAC clones, covering over 4.5 MB and containing 129 genes. When compared to the MHC region of the South American opossum, eutherian mammals and non-mammals, the Wallaby MHC has a novel gene organization. The Wallaby has undergone an expansion of MHC class II genes, which are separated into two clusters by the class III genes. The antigen processing genes have undergone duplication, resulting in two copies of TAP1 and three copies of TAP2. Notably, Kangaroo Endogenous Retroviral Elements are present within the region and may have contributed to the genomic instability. Conclusions: The Wallaby MHC has been extensively remodeled since the American and Australian marsupials last shared a common ancestor. The instability is characterized by the movement of antigen presenting genes away from the core MHC, most likely via the presence and activity of retroviral elements. We propose that the movement of class II genes away from the ancestral class II region has allowed this gene family to expand and diversify in the Wallaby. The duplication of TAP genes in the Wallaby MHC makes this species a unique model organism for studying the relationship between MHC gene organization and function.
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Physical Mapping of Immune Genes in the Tammar Wallaby (Macropus Eugenii)
Cytogenetic and genome research, 2009Co-Authors: Claire E. Sanderson, Katherine Belov, Janine E. DeakinAbstract:The tammar Wallaby (Macropus eugenii) is a model marsupial that has recently had its genome sequenced to a depth of 2-fold coverage. Although this is a great resource for comparative genomic studies, information on gene location is essential if this resource is to be used to its full potential. In this study, tammar Wallaby bacterial artificial chromosomes (BACs) containing key immune genes were isolated from the tammar Wallaby BAC library. BACs containing T cell receptor (TCR) and immunoglobulin (Ig) genes were physically mapped using fluorescence in situ hybridisation (FISH) to tammar Wallaby chromosomes. Congruence between the locations of these immune genes in the tammar Wallaby genome, with those predicted from chromosome painting data, highlights the conservation of genomic context of these important immune genes in marsupials. The isolation and mapping of these key immune genes in the tammar Wallaby will aid in the assembly of the recently sequenced light coverage genome and assignment of sequence to chromosomes.
Chenwei Wang - One of the best experts on this subject based on the ideXlab platform.
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A first-generation integrated tammar Wallaby map and its use in creating a tammar Wallaby first-generation virtual genome map
BMC Genomics, 2011Co-Authors: Chenwei Wang, Janine E. Deakin, Willem Rens, Kyall R. Zenger, Katherine Belov, Jennifer A. Marshall Graves, Frank W. NicholasAbstract:The limited (2X) coverage of the tammar Wallaby (Macropus eugenii) genome sequence dataset currently presents a challenge for assembly and anchoring onto chromosomes. To provide a framework for this assembly, it would be a great advantage to have a dense map of the tammar Wallaby genome. However, only limited mapping data are available for this non-model species, comprising a physical map and a linkage map. We combined all available tammar Wallaby mapping data to create a tammar Wallaby integrated map, using the Location DataBase (LDB) strategy. This first-generation integrated map combines all available information from the second-generation tammar Wallaby linkage map with 148 loci, and extensive FISH mapping data for 492 loci, especially for genes likely to be located at the ends of Wallaby chromosomes or at evolutionary breakpoints inferred from comparative information. For loci whose positions are only approximately known, their location in the integrated map was refined on the basis of comparative information from opossum (Monodelphis domestica) and human. Interpolation of segments from the opossum and human assemblies into the integrated map enabled the subsequent construction of a tammar Wallaby first-generation virtual genome map, which comprises 14336 markers, including 13783 genes recruited from opossum and human assemblies. Both maps are freely available at http://compldb.angis.org.au . The first-generation integrated map and the first-generation virtual genome map provide a backbone for the chromosome assembly of the tammar Wallaby genome sequence. For example, 78% of the 10257 gene-scaffolds in the Ensembl annotation of the tammar Wallaby genome sequence (including 10522 protein-coding genes) can now be given a chromosome location in the tammar Wallaby virtual genome map.
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a first generation integrated tammar Wallaby map and its use in creating a tammar Wallaby first generation virtual genome map
BMC Genomics, 2011Co-Authors: Janine E. Deakin, Chenwei Wang, Willem Rens, Kyall R. Zenger, Katherine Belov, Jennifer Marshall A GravesAbstract:Background: The limited (2X) coverage of the tammar Wallaby (Macropus eugenii) genome sequence dataset currently presents a challenge for assembly and anchoring onto chromosomes. To provide a framework for this assembly, it would be a great advantage to have a dense map of the tammar Wallaby genome. However, only limited mapping data are available for this non-model species, comprising a physical map and a linkage map. Results: We combined all available tammar Wallaby mapping data to create a tammar Wallaby integrated map, using the Location DataBase (LDB) strategy. This first-generation integrated map combines all available information from the second-generation tammar Wallaby linkage map with 148 loci, and extensive FISH mapping data for 492 loci, especially for genes likely to be located at the ends of Wallaby chromosomes or at evolutionary breakpoints inferred from comparative information. For loci whose positions are only approximately known, their location in the integrated map was refined on the basis of comparative information from opossum (Monodelphis domestica) and human. Interpolation of segments from the opossum and human assemblies into the integrated map enabled the subsequent construction of a tammar Wallaby first-generation virtual genome map, which comprises 14336 markers, including 13783 genes recruited from opossum and human assemblies. Both maps are freely available at http://compldb.angis.org.au. Conclusions: The first-generation integrated map and the first-generation virtual genome map provide a backbone for the chromosome assembly of the tammar Wallaby genome sequence. For example, 78% of the 10257 genescaffolds in the Ensembl annotation of the tammar Wallaby genome sequence (including 10522 protein-coding genes) can now be given a chromosome location in the tammar Wallaby virtual genome map.
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A second-generation anchored genetic linkage map of the tammar Wallaby (Macropus eugenii)
BMC genetics, 2011Co-Authors: Chenwei Wang, Janine E. Deakin, Jennifer A. Marshall Graves, Lee Webley, Ke-jun Wei, Matthew J. Wakefield, Hardip R. Patel, Amber E. Alsop, Desmond W. Cooper, Frank W. NicholasAbstract:The tammar Wallaby, Macropus eugenii, a small kangaroo used for decades for studies of reproduction and metabolism, is the model Australian marsupial for genome sequencing and genetic investigations. The production of a more comprehensive cytogenetically-anchored genetic linkage map will significantly contribute to the deciphering of the tammar Wallaby genome. It has great value as a resource to identify novel genes and for comparative studies, and is vital for the ongoing genome sequence assembly and gene ordering in this species. A second-generation anchored tammar Wallaby genetic linkage map has been constructed based on a total of 148 loci. The linkage map contains the original 64 loci included in the first-generation map, plus an additional 84 microsatellite loci that were chosen specifically to increase coverage and assist with the anchoring and orientation of linkage groups to chromosomes. These additional loci were derived from (a) sequenced BAC clones that had been previously mapped to tammar Wallaby chromosomes by fluorescence in situ hybridization (FISH), (b) End sequence from BACs subsequently FISH-mapped to tammar Wallaby chromosomes, and (c) tammar Wallaby genes orthologous to opossum genes predicted to fill gaps in the tammar Wallaby linkage map as well as three X-linked markers from a published study. Based on these 148 loci, eight linkage groups were formed. These linkage groups were assigned (via FISH-mapped markers) to all seven autosomes and the X chromosome. The sex-pooled map size is 1402.4 cM, which is estimated to provide 82.6% total coverage of the genome, with an average interval distance of 10.9 cM between adjacent markers. The overall ratio of female/male map length is 0.84, which is comparable to the ratio of 0.78 obtained for the first-generation map. Construction of this second-generation genetic linkage map is a significant step towards complete coverage of the tammar Wallaby genome and considerably extends that of the first-generation map. It will be a valuable resource for ongoing tammar Wallaby genetic research and assembling the genome sequence. The sex-pooled map is available online at http://compldb.angis.org.au/.
Mark D B Eldridge - One of the best experts on this subject based on the ideXlab platform.
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genetic consequences of isolation island tammar Wallaby macropus eugenii populations and the conservation of threatened species
Conservation Genetics, 2011Co-Authors: Kyall R. Zenger, Emily J Miller, Mark D B Eldridge, Keith D Morris, Catherine A HerbertAbstract:Isolation and restricted gene flow can lead to genetic deterioration in populations. Populations of many species are increasingly becoming fragmented due to human impacts and active management is required to prevent further extinctions. Islands provide an ideal location to protect species from many mainland threatening processes such as habitat loss and fragmentation, disease and competition/predation from introduced species. However their isolation and small population size renders them prone to loss of genetic diversity and to inbreeding. This study examined two endemic and one introduced population of tammar Wallaby (Macropus eugenii) on three islands in the Houtman Abrolhos Archipelago, Western Australia: East Wallabi (EWI), West Wallabi (WWI) and North Islands (NI). Nine autosomal and four Y-linked microsatellite loci, and sequence data from the mitochondrial DNA (mtDNA) control region were used to examine the impact of long-term isolation (EWI and WWI) and small founder size (NI) on genetic diversity and inbreeding. This study found all three populations had low genetic diversity, high levels of effective inbreeding and increased frequency of morphological abnormalities. Isolation has also led to significant inter-population genetic differentiation. These results highlight the importance of incorporating genetic management strategies when utilising islands as refuges for declining mainland populations.
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isolation and characterization of 10 mhc class i associated microsatellite loci in tammar Wallaby macropus eugenii
Molecular Ecology Resources, 2009Co-Authors: Yuanyuan Cheng, Katherine Belov, Catherine A Herbert, Matthew J. Wakefield, Hannah V Siddle, Penny Coggill, Stephan Beck, Mark D B EldridgeAbstract:The major histocompatibility complex (MHC) contain genes which play a key role in immune response and mate choice, and are therefore of functional importance to molecular ecologists. Here we describe the design of 10 MHC Class I-associated microsatellite loci from the tammar Wallaby. All 10 loci are highly polymorphic, with the expected heterozygosity ranging from 0.547 to 0.919. Six loci successfully cross-amplify in other macropodid species. These microsatellites will serve as useful tools for studying the level of MHC diversity, the impact of selection on genetic variation and the unique structure of the tammar Wallaby MHC.
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fine scale spatial genetic correlation analyses reveal strong female philopatry within a brush tailed rock Wallaby colony in southeast queensland
Molecular Ecology, 2004Co-Authors: Stephanie L Hazlitt, Mark D B Eldridge, Anne W GoldizenAbstract:We combine spatial data on home ranges of individuals and microsatellite markers to examine patterns of fine-scale spatial genetic structure and dispersal within a brush-tailed rock-Wallaby (Petrogale penicillata) colony at Hurdle Creek Valley, Queensland. Brush-tailed rock-wallabies were once abundant and widespread throughout the rocky terrain of southeastern Australia; however, populations are nearly extinct in the south of their range and in decline elsewhere. We use pairwise relatedness measures and a recent multilocus spatial autocorrelation analysis to test the hypotheses that in this species, within-colony dispersal is male-biased and that female philopatry results in spatial clusters of related females within the colony. We provide clear evidence for strong female philopatry and male-biased dispersal within this rock-Wallaby colony. There was a strong, significant negative correlation between pairwise relatedness and geographical distance of individual females along only 800 m of cliff line. Spatial genetic autocorrelation analyses showed significant positive correlation for females in close proximity to each other and revealed a genetic neighbourhood size of only 600 m for females. Our study is the first to report on the fine-scale spatial genetic structure within a rock-Wallaby colony and we provide the first robust evidence for strong female philopatry and spatial clustering of related females within this taxon. We discuss the ecological and conservation implications of our findings for rock-wallabies, as well as the importance of fine-scale spatial genetic patterns in studies of dispersal behaviour.
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Taxonomy of rock-wallabies, Petrogale (Marsupialia: Macropodidae). III. Molecular data confirms the species status of the purple-necked rock-Wallaby (Petrogale purpureicollis Le Souef)
Australian Journal of Zoology, 2001Co-Authors: Mark D B Eldridge, Alex C. C. Wilson, Cushla J. Metcalfe, Anne E Dollin, Jane M Bell, P. M Johnson, P. G. Johnston, Robert CloseAbstract:Mitochondrial DNA (mtDNA) analysis was undertaken to resolve the systematic uncertainties surrounding the morphologically distinct purple-necked rock-Wallaby (P. lateralis purpureicollis) of north-west Queensland, Australia. A comparison of mtDNA sequence divergence using both whole mtDNA restriction site and control-region sequence analyses revealed that P. l. purpureicollis was as well differentiated from other P. lateralis (black-footed rock-Wallaby) taxa as P. lateralis was from P. penicillata (brush-tailed rock-Wallaby) or P. assimilis (allied rock-Wallaby). Phylogenetic analysis of the sequence data suggests thatP. lateralis (sensu lato) is paraphyletic, with P. l. purpureicollis being more closely aligned to P. penicillataand P. assimilis than to P. lateralis (sensu stricto). Data are also presented that demonstrate significant differences in the distribution of the telomeric repeat sequence (TTAGGG)n between the chromosomes of P. l. purpureicollis and the karyotypically similar MacDonnell Ranges race of P. lateralis. In addition, meiosis appears to be severely disrupted in the majority (73%) of oocytes examined from two P. l. purpureicollis MacDonnell Ranges race hybrids. In light of these findings we recommend that the purple-necked rock-Wallaby be reinstated as a full species, P. purpureicollis Le Souef 1924.
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Chromosome evolution in kangaroos (Marsupialia: Macropodidae): Cross species chromosome painting between the tammar Wallaby and rock Wallaby spp. with the 2n = 22 ancestral macropodid karyotype
Genome, 1999Co-Authors: R. J. Waugh O'neill, Mark D B Eldridge, Roland Toder, Malcolm A. Ferguson-smith, Patricia Caroline Mary O’brien, Jennifer A. Marshall GravesAbstract:Marsupial mammals show extraordinary karyotype stability, with 2n = 14 considered ancestral. However, macropodid marsupials (kangaroos and wallabies) exhibit a considerable variety of karyotypes, with a hypothesised ancestral karyotype of 2n = 22. Speciation and karyotypic diversity in rock wallabies (Petrogale) is exceptional. We used cross species chromosome painting to examine the chromosome evolution between the tammar Wallaby (2n = 16) and three 2n = 22 rock Wallaby species groups with the putative ancestral karyotype. Hybridization of chromosome paints prepared from flow sorted chromosomes of the tammar Wallaby to Petrogale spp., showed that this ancestral karyotype is largely conserved among 2n = 22 rock Wallaby species, and confirmed the identity of ancestral chromosomes which fused to produce the bi-armed chromosomes of the 2n = 16 tammar Wallaby. These results illustrate the fission-fusion process of karyotype evolution characteristic of the kangaroo group.
