The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Alexandre Hassanin - One of the best experts on this subject based on the ideXlab platform.
-
molecular phylogeny of the tribe bovini Bovidae bovinae and the taxonomic status of the kouprey bos sauveli urbain 1937
Molecular Phylogenetics and Evolution, 2004Co-Authors: Alexandre Hassanin, Anne RopiquetAbstract:The kouprey is a very rare bovid species of the Indochinese peninsula, and no living specimen has been described for a long time, suggesting that it is possibly extinct. Its systematic position within the tribe Bovini remains confused since the analyses of morphological characters have led to several conflicting hypotheses. Some authors have also suggested that it could be a hybrid species produced by the crossing of the banteng with gaur, zebu, or water buffalo. Here we performed a molecular phylogeny of the tribe Bovini to determine the taxonomic status of the kouprey. DNA was extracted from the holotype specimen preserved in the MNHN collections. Phylogenetic analyses were carried out on a matrix including all the taxonomic diversity described in the tribe Bovini, and 2065 nucleotide characters, representing three different markers, i.e., the promotor of the lactoferrin and two mitochondrial genes (cytochrome b and subunit II of the cytochrome c oxidase). The results show that the kouprey belongs to the subtribe Bovina, and that three different clades can be evidenced into this group: the first includes the domestic ox, zebu, and European bison; the second incorporates the yak and American bison; and the third contains the kouprey, banteng and gaur. All hypotheses involving hybridization for the origin of the kouprey can be rejected, confirming that it is a real wild species. Molecular datings and biogeographic inferences suggest that the kouprey diverged from banteng and gaur during the Plio-Pleistocene of Asia. In addition, several molecular signatures were detected in the cytochrome b gene, permitting a molecular identification of the kouprey. We propose a conservation project based on a molecular taxonomy approach for tracking the kouprey in Indochina in order to determine whether some populations still survive in the wild.
-
Molecular and Morphological Phylogenies of Ruminantia and the Alternative Position of the Moschidae
Systematic Biology, 2003Co-Authors: Alexandre Hassanin, Emmanuel J P DouzeryAbstract:The ruminants constitute the largest group of ungulates, with >190 species, and its distribution is widespread throughout all continents except Australia and Antarctica. Six families are traditionally recognized within the suborder Ruminantia: Antilocapridae (pronghorns), Bovidae (cattle, sheep, and antelopes), Cervidae (deer), Giraffidae (giraffes and okapis), Moschidae (musk deer), and Tragulidae (chevrotains). The interrelationships of the families have been an area of controversy among morphology, palaeontology, and molecular studies, and almost all possible evolutionary scenarios have been proposed in the literature. We analyzed a large DNA data set (5,322 nucleotides) for 23 species including both mito- chondrial (cytochrome b, 12S ribosomal RNA (rRNA), and 16S rRNA) and nuclear (•-casein, cytochrome P-450, lactoferrin, andfi-lactalbumin) markers. Our results show that the family Tragulidae occupies a basal position with respect to all other ruminant families, confirming the traditional view that separates Tragulina and Pecora. Within the pecorans, Antilocapridae and Giraffidae emerge first, and the families Bovidae, Moschidae, and Cervidae are allied, with the unexpected placement of Moschus close to bovids rather than to cervids. We used these molecular results to assess the homoplastic evolution of morphological characters within the Ruminantia. A Bayesian relaxed molecular clock approach based on the continuous autocorrelation of evolutionary rates along branches was applied to estimate the divergence ages between the major clades of ruminants. The evolutionary radiation of Pecora occurred at the Early/Late Oligocene transition, and Pecoran families diversified and dispersed rapidly during the Early and Middle Miocene. We propose a biogeographic scenario to explain the extraordinary expansion of this group during the Cenozoic era. (Bayesian relaxed clock; Bovidae; molecules; morphology; Moschidae; phylogeny; Ruminantia.)
-
the tribal radiation of the family Bovidae artiodactyla and the evolution of the mitochondrial cytochrome b gene
Molecular Phylogenetics and Evolution, 1999Co-Authors: Alexandre Hassanin, Emmanuel J P DouzeryAbstract:Abstract The nucleotide sequence of the complete mitochondrial cytochrome b gene has been determined and compared for 51 species of the family Bovidae and 10 potential pecoran and tragulid outgroups. A detailed saturation analysis at each codon position relative to the maximum parsimony procedure indicates that all transitions on third codon positions do not accumulate in a similar fashion: C-T are more saturated than A-G substitutions. The same trend is observed for second positions but not for first positions where A-G and C-T transitions exhibit roughly the same levels of saturation. Maximum parsimony reconstructions were weighted according to these observations. Maximum parsimony, maximum likelihood, and distance phylogenetic reconstructions all depict a major split within Bovidae. The subfamily Bovinae includes four multifurcating tribes and subtribes: Boselaphini, Tragelaphini, cattle-Bovini (Bos and Bison), and buffalo-Bovini (Bubalus and Syncerus). Its sister group is the subfamily Antilopinae, i.e., all non-Bovinae taxa, represented by seven lineages: Antilopini (including Saiga), Caprini sensu lato (i.e., Caprinae including Pantholops), Hippotragini, Alcelaphini, Reduncini (including Pelea), Aepyceros possibly linked to Neotragus, and Cephalophini possibly linked to Oreotragus (the suni and the klipspringer being members of a polyphyletic Neotragini). These various tribes and major lineages were produced by two noteworthy explosive radiations, which occurred simultaneously between 12.0 and 15.3 MY (Middle Miocene) in the subfamilies Bovinae and Antilopinae.
-
Evolutionary affinities of the enigmatic saola (Pseudoryx nghetinhensis) in the context of the molecular phylogeny of Bovidae
Proceedings of The Royal Society B: Biological Sciences, 1999Co-Authors: Alexandre Hassanin, Emmanuel J P DouzeryAbstract:To elucidate the systematic status of the enigmatic saola (Pseudoryx nghetinhensis), a new bovid genus recently discovered in Vietnam, and to investigate phylogenetic relationships within the family Bovidae, four distinct DNA markers were sequenced. Complete mitochondrial cytochrome b (1143 bp) and 12S rRNA (956 bp) genes and non-coding regions from the nuclear genes for aromatase cytochrome P-450 (199 bp) and lactoferrin (338 bp) have been compared for 25 bovid species and three Cervidae and Antilocapridae outgroups. Independent and/or combined analyses of the four nucleotide matrices through maximum parsimony and maximum-likelihood methods indicated that Bovidae consists of two major lineages, i.e. Bovinac which contains the tribes Bovini, Boselaphini and Tragelaphini, and Antilopinae which encompasses all other bovids. Within Bovinae, the tribe Bovini is divided into buffalo Bovini (Bubalus and Syncerus) and cattle Bovini (Bos and Bison) and Tragelaphini are possibly related to Boselaphini. Pseudoryx is shown to be (i) robustly nested within Bovinae; (ii) strongly associated with Bovini; and (iii) tentatively sharing a sister-group relationship with cattle Bovini. Within Antilopinae, three robust clades are in evidence: (i) Hippotragus and Damaliscus are linked to Ovis; (ii) Aepyceros joins Neotragus; and (iii) Cephalophus clusters with Oreotragus.
A. T. Kumamoto - One of the best experts on this subject based on the ideXlab platform.
-
A Molecular Cytogenetic Analysis of the Tribe Bovini (Artiodactyla: Bovidae: Bovinae) with an Emphasis on Sex Shromosome Morphology and NOR Distribution
Chromosome Research, 1999Co-Authors: D. S. Gallagher, S. K. Davis, M. De Donato, J. D. Burzlaff, J. E. Womack, J. F. Taylor, A. T. KumamotoAbstract:Q-band comparisons were made among representative species of the four genera of the tribe Bovini (Bos, Bison, Bubalus, Syncerus) as well as to selected outgroup taxa representing the remaining two tribes of the subfamily Bovinae (nilgai, Boselaphini; eland, Tragelphini), the Bovidae subfamily Caprinae (domestic sheep) and the family Cervidae (sika deer and white- tailed deer). Extensive autosomal arm homologies were noted, but relatively few derivative character states were shared. Focus was then made on variation of the sex chromosomes and the chromosomal distribution of nucleolar organizer regions (NORs). Bovine BAC clones were used in molecular cytogenetic analyses to decipher rearrangements of the sex chromosomes, and a pocket gopher 28s ribosomal probe was used to map the chromosomal locations of nucleolar organizing regions (NORs). Some of the more noteworthy conclusions drawn from the comparative analysis were that: 1. The Bovidae ancestral X chromosome was probably acrocentric and similar to acrocentric X chromosomes of the Bovinae; 2. The domestic sheep acrocentric X is probably a deriative character state that unites non-Bovinae subfamilies; 3. Bos and Bison are united within the tribe Bovini by the presence of shared derivative submetacentric X chromosomes; 4. Sika and white- tailed deer X chromosomes differ by inversion from X chromosomes of the Bovinae; 5. The Bovini ancestral Y chromosome was probably a small acrocentric; 6. Bos taurus, B. gaurus and B. banteng share derivative metacentric Y chromosomes; 7. Syncerus and Bubalus are united by the acquisition of X-specific repetitive DNA sequence on their Y chromosomes; 8. Bovinae and Cervidae X chromosome centromere position varies without concomitant change in locus order. Preliminary data indicate that a knowledge of the chromosomal distribution of NORs among the Bovidae will prove to be phylogenetically informative.
-
a molecular cytogenetic analysis of the tribe bovini artiodactyla Bovidae bovinae with an emphasis on sex chromosome morphology and nor distribution
Chromosome Research, 1999Co-Authors: D. S. Gallagher, Scott K. Davis, M. De Donato, J. D. Burzlaff, J. E. Womack, J. F. Taylor, A. T. KumamotoAbstract:Q-band comparisons were made among representative species of the four genera of the tribe Bovini (Bos, Bison, Bubalus, Syncerus) as well as to selected outgroup taxa representing the remaining two tribes of the subfamily Bovinae (nilgai, Boselaphini; eland, Tragelphini), the Bovidae subfamily Caprinae (domestic sheep) and the family Cervidae (sika deer and white- tailed deer). Extensive autosomal arm homologies were noted, but relatively few derivative character states were shared. Focus was then made on variation of the sex chromosomes and the chromosomal distribution of nucleolar organizer regions (NORs). Bovine BAC clones were used in molecular cytogenetic analyses to decipher rearrangements of the sex chromosomes, and a pocket gopher 28s ribosomal probe was used to map the chromosomal locations of nucleolar organizing regions (NORs). Some of the more noteworthy conclusions drawn from the comparative analysis were that: 1. The Bovidae ancestral X chromosome was probably acrocentric and similar to acrocentric X chromosomes of the Bovinae; 2. The domestic sheep acrocentric X is probably a deriative character state that unites non-Bovinae subfamilies; 3. Bos and Bison are united within the tribe Bovini by the presence of shared derivative submetacentric X chromosomes; 4. Sika and white- tailed deer X chromosomes differ by inversion from X chromosomes of the Bovinae; 5. The Bovini ancestral Y chromosome was probably a small acrocentric; 6. Bos taurus, B. gaurus and B. banteng share derivative metacentric Y chromosomes; 7. Syncerus and Bubalus are united by the acquisition of X-specific repetitive DNA sequence on their Y chromosomes; 8. Bovinae and Cervidae X chromosome centromere position varies without concomitant change in locus order. Preliminary data indicate that a knowledge of the chromosomal distribution of NORs among the Bovidae will prove to be phylogenetically informative.
Gerald A. H. Wells - One of the best experts on this subject based on the ideXlab platform.
-
Bovine spongiform encephalopathy infectivity in greater kudu (Tragelaphus strepsiceros).
Emerging Infectious Diseases, 2004Co-Authors: Andrew A. Cunningham, James K. Kirkwood, Y. I. Spencer, Robert B. Green, M Dawson, Gerald A. H. WellsAbstract:To date, 13 species of zoo animal have been confirmed as having died with a novel scrapie-like spongiform encephalopathy (SE) concurrent with the bovine spongiform encephalopathy (BSE) epidemic (Table 1). The disease is thought, in some, if not all, of these species, to be caused by infection with the BSE agent. In addition, natural infection with BSE has been reported in five species of primate in French zoos (11), but these results are considered equivocal for the confirmation of a spongiform encephalopathy (12, G.A.H. Wells, unpub. data). BSE was diagnosed in six of eight greater kudu (Tragelaphus strepsiceros), a member of the family Bovidae, subfamily Bovinae, that died at the London Zoo from 1989 through 1992 (2,13,14). The epidemiology of this disease in greater kudu is consistent with either a particularly high susceptibility to infection, the occurrence of direct animal-to-animal transmission of the disease, or with a combination of these factors (2,14,15). To investigate further the biology of BSE in greater kudu, the distribution of the infectious agent in greater kudu with BSE was determined by using the mouse bioassay method. Table 1 Species of zoo animal with confirmed novel spongiform encephalopathy required contemporaneously with epidemic of bovine spongiform encephalopathy in domestic cattlea
-
Bovine spongiform encephalopathy infectivity in greater kudu (Tragelaphus strepsiceros).
Emerging Infectious Diseases, 2004Co-Authors: Andrew A. Cunningham, James K. Kirkwood, Y. I. Spencer, Robert B. Green, M Dawson, Gerald A. H. WellsAbstract:To date, 13 species of zoo animal have been confirmed as having died with a novel scrapie-like spongiform encephalopathy (SE) concurrent with the bovine spongiform encephalopathy (BSE) epidemic (Table 1). The disease is thought, in some, if not all, of these species, to be caused by infection with the BSE agent. In addition, natural infection with BSE has been reported in five species of primate in French zoos (11), but these results are considered equivocal for the confirmation of a spongiform encephalopathy (12, G.A.H. Wells, unpub. data). BSE was diagnosed in six of eight greater kudu (Tragelaphus strepsiceros), a member of the family Bovidae, subfamily Bovinae, that died at the London Zoo from 1989 through 1992 (2,13,14). The epidemiology of this disease in greater kudu is consistent with either a particularly high susceptibility to infection, the occurrence of direct animal-to-animal transmission of the disease, or with a combination of these factors (2,14,15). To investigate further the biology of BSE in greater kudu, the distribution of the infectious agent in greater kudu with BSE was determined by using the mouse bioassay method. Table 1 Species of zoo animal with confirmed novel spongiform encephalopathy required contemporaneously with epidemic of bovine spongiform encephalopathy in domestic cattlea
Emmanuel J P Douzery - One of the best experts on this subject based on the ideXlab platform.
-
Molecular and Morphological Phylogenies of Ruminantia and the Alternative Position of the Moschidae
Systematic Biology, 2003Co-Authors: Alexandre Hassanin, Emmanuel J P DouzeryAbstract:The ruminants constitute the largest group of ungulates, with >190 species, and its distribution is widespread throughout all continents except Australia and Antarctica. Six families are traditionally recognized within the suborder Ruminantia: Antilocapridae (pronghorns), Bovidae (cattle, sheep, and antelopes), Cervidae (deer), Giraffidae (giraffes and okapis), Moschidae (musk deer), and Tragulidae (chevrotains). The interrelationships of the families have been an area of controversy among morphology, palaeontology, and molecular studies, and almost all possible evolutionary scenarios have been proposed in the literature. We analyzed a large DNA data set (5,322 nucleotides) for 23 species including both mito- chondrial (cytochrome b, 12S ribosomal RNA (rRNA), and 16S rRNA) and nuclear (•-casein, cytochrome P-450, lactoferrin, andfi-lactalbumin) markers. Our results show that the family Tragulidae occupies a basal position with respect to all other ruminant families, confirming the traditional view that separates Tragulina and Pecora. Within the pecorans, Antilocapridae and Giraffidae emerge first, and the families Bovidae, Moschidae, and Cervidae are allied, with the unexpected placement of Moschus close to bovids rather than to cervids. We used these molecular results to assess the homoplastic evolution of morphological characters within the Ruminantia. A Bayesian relaxed molecular clock approach based on the continuous autocorrelation of evolutionary rates along branches was applied to estimate the divergence ages between the major clades of ruminants. The evolutionary radiation of Pecora occurred at the Early/Late Oligocene transition, and Pecoran families diversified and dispersed rapidly during the Early and Middle Miocene. We propose a biogeographic scenario to explain the extraordinary expansion of this group during the Cenozoic era. (Bayesian relaxed clock; Bovidae; molecules; morphology; Moschidae; phylogeny; Ruminantia.)
-
the tribal radiation of the family Bovidae artiodactyla and the evolution of the mitochondrial cytochrome b gene
Molecular Phylogenetics and Evolution, 1999Co-Authors: Alexandre Hassanin, Emmanuel J P DouzeryAbstract:Abstract The nucleotide sequence of the complete mitochondrial cytochrome b gene has been determined and compared for 51 species of the family Bovidae and 10 potential pecoran and tragulid outgroups. A detailed saturation analysis at each codon position relative to the maximum parsimony procedure indicates that all transitions on third codon positions do not accumulate in a similar fashion: C-T are more saturated than A-G substitutions. The same trend is observed for second positions but not for first positions where A-G and C-T transitions exhibit roughly the same levels of saturation. Maximum parsimony reconstructions were weighted according to these observations. Maximum parsimony, maximum likelihood, and distance phylogenetic reconstructions all depict a major split within Bovidae. The subfamily Bovinae includes four multifurcating tribes and subtribes: Boselaphini, Tragelaphini, cattle-Bovini (Bos and Bison), and buffalo-Bovini (Bubalus and Syncerus). Its sister group is the subfamily Antilopinae, i.e., all non-Bovinae taxa, represented by seven lineages: Antilopini (including Saiga), Caprini sensu lato (i.e., Caprinae including Pantholops), Hippotragini, Alcelaphini, Reduncini (including Pelea), Aepyceros possibly linked to Neotragus, and Cephalophini possibly linked to Oreotragus (the suni and the klipspringer being members of a polyphyletic Neotragini). These various tribes and major lineages were produced by two noteworthy explosive radiations, which occurred simultaneously between 12.0 and 15.3 MY (Middle Miocene) in the subfamilies Bovinae and Antilopinae.
-
Evolutionary affinities of the enigmatic saola (Pseudoryx nghetinhensis) in the context of the molecular phylogeny of Bovidae
Proceedings of The Royal Society B: Biological Sciences, 1999Co-Authors: Alexandre Hassanin, Emmanuel J P DouzeryAbstract:To elucidate the systematic status of the enigmatic saola (Pseudoryx nghetinhensis), a new bovid genus recently discovered in Vietnam, and to investigate phylogenetic relationships within the family Bovidae, four distinct DNA markers were sequenced. Complete mitochondrial cytochrome b (1143 bp) and 12S rRNA (956 bp) genes and non-coding regions from the nuclear genes for aromatase cytochrome P-450 (199 bp) and lactoferrin (338 bp) have been compared for 25 bovid species and three Cervidae and Antilocapridae outgroups. Independent and/or combined analyses of the four nucleotide matrices through maximum parsimony and maximum-likelihood methods indicated that Bovidae consists of two major lineages, i.e. Bovinac which contains the tribes Bovini, Boselaphini and Tragelaphini, and Antilopinae which encompasses all other bovids. Within Bovinae, the tribe Bovini is divided into buffalo Bovini (Bubalus and Syncerus) and cattle Bovini (Bos and Bison) and Tragelaphini are possibly related to Boselaphini. Pseudoryx is shown to be (i) robustly nested within Bovinae; (ii) strongly associated with Bovini; and (iii) tentatively sharing a sister-group relationship with cattle Bovini. Within Antilopinae, three robust clades are in evidence: (i) Hippotragus and Damaliscus are linked to Ovis; (ii) Aepyceros joins Neotragus; and (iii) Cephalophus clusters with Oreotragus.
D. S. Gallagher - One of the best experts on this subject based on the ideXlab platform.
-
A Molecular Cytogenetic Analysis of the Tribe Bovini (Artiodactyla: Bovidae: Bovinae) with an Emphasis on Sex Shromosome Morphology and NOR Distribution
Chromosome Research, 1999Co-Authors: D. S. Gallagher, S. K. Davis, M. De Donato, J. D. Burzlaff, J. E. Womack, J. F. Taylor, A. T. KumamotoAbstract:Q-band comparisons were made among representative species of the four genera of the tribe Bovini (Bos, Bison, Bubalus, Syncerus) as well as to selected outgroup taxa representing the remaining two tribes of the subfamily Bovinae (nilgai, Boselaphini; eland, Tragelphini), the Bovidae subfamily Caprinae (domestic sheep) and the family Cervidae (sika deer and white- tailed deer). Extensive autosomal arm homologies were noted, but relatively few derivative character states were shared. Focus was then made on variation of the sex chromosomes and the chromosomal distribution of nucleolar organizer regions (NORs). Bovine BAC clones were used in molecular cytogenetic analyses to decipher rearrangements of the sex chromosomes, and a pocket gopher 28s ribosomal probe was used to map the chromosomal locations of nucleolar organizing regions (NORs). Some of the more noteworthy conclusions drawn from the comparative analysis were that: 1. The Bovidae ancestral X chromosome was probably acrocentric and similar to acrocentric X chromosomes of the Bovinae; 2. The domestic sheep acrocentric X is probably a deriative character state that unites non-Bovinae subfamilies; 3. Bos and Bison are united within the tribe Bovini by the presence of shared derivative submetacentric X chromosomes; 4. Sika and white- tailed deer X chromosomes differ by inversion from X chromosomes of the Bovinae; 5. The Bovini ancestral Y chromosome was probably a small acrocentric; 6. Bos taurus, B. gaurus and B. banteng share derivative metacentric Y chromosomes; 7. Syncerus and Bubalus are united by the acquisition of X-specific repetitive DNA sequence on their Y chromosomes; 8. Bovinae and Cervidae X chromosome centromere position varies without concomitant change in locus order. Preliminary data indicate that a knowledge of the chromosomal distribution of NORs among the Bovidae will prove to be phylogenetically informative.
-
a molecular cytogenetic analysis of the tribe bovini artiodactyla Bovidae bovinae with an emphasis on sex chromosome morphology and nor distribution
Chromosome Research, 1999Co-Authors: D. S. Gallagher, Scott K. Davis, M. De Donato, J. D. Burzlaff, J. E. Womack, J. F. Taylor, A. T. KumamotoAbstract:Q-band comparisons were made among representative species of the four genera of the tribe Bovini (Bos, Bison, Bubalus, Syncerus) as well as to selected outgroup taxa representing the remaining two tribes of the subfamily Bovinae (nilgai, Boselaphini; eland, Tragelphini), the Bovidae subfamily Caprinae (domestic sheep) and the family Cervidae (sika deer and white- tailed deer). Extensive autosomal arm homologies were noted, but relatively few derivative character states were shared. Focus was then made on variation of the sex chromosomes and the chromosomal distribution of nucleolar organizer regions (NORs). Bovine BAC clones were used in molecular cytogenetic analyses to decipher rearrangements of the sex chromosomes, and a pocket gopher 28s ribosomal probe was used to map the chromosomal locations of nucleolar organizing regions (NORs). Some of the more noteworthy conclusions drawn from the comparative analysis were that: 1. The Bovidae ancestral X chromosome was probably acrocentric and similar to acrocentric X chromosomes of the Bovinae; 2. The domestic sheep acrocentric X is probably a deriative character state that unites non-Bovinae subfamilies; 3. Bos and Bison are united within the tribe Bovini by the presence of shared derivative submetacentric X chromosomes; 4. Sika and white- tailed deer X chromosomes differ by inversion from X chromosomes of the Bovinae; 5. The Bovini ancestral Y chromosome was probably a small acrocentric; 6. Bos taurus, B. gaurus and B. banteng share derivative metacentric Y chromosomes; 7. Syncerus and Bubalus are united by the acquisition of X-specific repetitive DNA sequence on their Y chromosomes; 8. Bovinae and Cervidae X chromosome centromere position varies without concomitant change in locus order. Preliminary data indicate that a knowledge of the chromosomal distribution of NORs among the Bovidae will prove to be phylogenetically informative.