The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
Bernard Le Jeune - One of the best experts on this subject based on the ideXlab platform.
-
quantitative developmental analysis of homeotic changes in the inflorescence of philodendron araceae
Annals of Botany, 2008Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:† Background and Aims The inflorescence of Philodendron constitutes an interesting morphological model to analyse the phenomenon of Homeosis quantitatively at the floral level. The specific goals of this study were (1) to characterize and quantify the range of homeotic transformation in Philodendron billietiae, and (2) to test the hypothesis that the nature of flowers surrounding atypical bisexual flowers (ABFs) channel the morphological potentialities of atypical bisexual flowers. † Methods Inflorescences of P. billietiae at different stages of development were observed using SEM. The number of appendices in male, female and sterile flowers were counted on 11 young inflorescences (5 – 6 flowers per inflorescence). The number of staminodes and carpels on ABFs were counted on 19 inflorescences (n ¼ 143). These data were used for regression and ANOVA analyses. † Results There was an average of 4.1 stamens per male flower, 9.8 carpels per female flower and 6.8 staminodes per sterile male flower. There was an average of 7.3 floral appendices per atypical flower. Staminodes and carpels are inserted on the same whorl in ABFs. A negative exponential relationship was found between the average number of staminodes and the number of carpels in ABFs. If only the ABFs consisting of less than six carpels are considered, there is a linear relationship between the number of carpels and the average number of staminodes. The value of the slope of the regression equation indicates that on average, in P. billietiae ,1 .36 carpels are replaced by one staminode. † Conclusions In P. billietiae, the number of appendages in female flowers imposes a constraint on the maximum total number of appendages (carpels and staminodes) that can develop on ABFs. The quantitative analyses indicate that the average number of different types of floral appendages on an ABF and the number of organs involved in a homeotic transformation are two independent phenomena.
-
the game of numbers in homeotic flowers of philodendron araceae
Botany, 2004Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:In Philodendron, pistillate flowers are initiated on the proximal portion of the inflorescence and staminate flowers are initiated on the distal portion. Between the staminate and pistillate flowers, there is a transition zone con- sisting of sterile male flowers adjacent to the male zone and a row of atypical bisexual flowers between the sterile male zone and the female zone. The portion of the atypical bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops into an incomplete gynoecium with few carpels. The atypical bisexual flowers of Philodendron are believed to be a case of Homeosis where carpels are replaced by sterile stamens on the same whorl. In Philodendron melinonii Brongniart ex Regel, Philodendron pedatum (Hooker) Kunth, Philodendron squamiferum Poeppig., and Philodendron solimoesense A.C. Smith, there is a significant quantitative relationship be- tween the number of carpels and the number of staminodes involved in the homeotic transformation in atypical bisex- ual flowers. On the other hand, such a significant correlation does not exist in Philodendron fragrantissimum (Hooker) Kunth and Philodendron insigne Schott, and Philodendron callosum K. Krause. There is a one to one organ replace- ment in homeotic flowers in both P. pedatum and P. squamiferum whereas, in P. solimoesense, an average of 2.56 staminodes replace one carpel. The average number of organs developing on an atypical bisexual flower and the num- ber of organs involved in a homeotic transformation appear to be two independent phenomena. The number of carpels in female flowers is correlated with the maximum total number of appendages (carpels and staminodes) that can de- velop in atypical bisexual flowers. Resume : Chez les Philodendron, les fleurs pistillees sont inserees dans la partie inferieure de l'inflorescence et les fleurs staminees dans la partie superieure. Entre la zone femelle et la zone mâle, se trouve une zone intermediaire formee de fleurs steriles mâles. Une rangee de fleurs bisexuees atypiques est presente entre la zone sterile et la zone femelle. La partie des fleurs bisexuees atypiques, placee du cote de la zone sterile, est formee de staminodes, et la partie situee du cote des fleurs femelles se developpe en un gynecee incomplet. Les fleurs bisexuees atypiques des Phi- lodendron presentent un cas d'Homeosis ou les carpelles sont remplaces par des staminodes sur un meme verticille. Chez les Philodendron melinonii Brongniart ex Regel, Philodendron pedatum (Hooker) Kunth, Philodendron squamife- rum Poeppig et Philodendron solimoesense A.C. Smith, il existe une relation quantitative significative entre le nombre de carpelles et le nombre de staminodes impliques dans une transformation homeotique, chez les fleurs bisexuees atypi- ques. On ne retrouve pas cette correlation significative chez les Philodendron fragrantissimum (Hooker) Kunth, Philo- dendron insigne Schott, et Philodendron callosum K. Krause. En moyenne, chez les P. pedatum ,e tP. squamiferum ,u n staminode remplace un carpelle, alors que chez le P. solimoesence 2,56 staminodes remplacent un carpelle. Le nombre moyen d'organes se developpant dans les fleurs bisexuees atypiques et le nombre d'organes impliques dans une trans- formation homeotique semblent provenir de deux phenomenes independants. Le nombre de carpelles presents dans les fleurs femelles est correle avec le nombre maximum d'appendices (carpelles et staminodes) pouvant se former dans les fleurs bisexuees atypiques. Mots cles : developpement, inflorescence, gradient, position, information.
-
study of Homeosis in the flower of philodendron araceae a qualitative and quantitative approach
Annals of Botany, 2002Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:This study deals specifically with floral organogenesis and the development of the inflorescence of Philodendron squamiferum and P. pedatum. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. An intermediate zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is also present. This zone is located between the sterile male and female floral zones. In general, the portion of bisexual flowers facing the male zone forms staminodes, and the portion facing the female zone develops an incomplete gynoecium with few carpels. The incomplete separation of some staminodes from the gynoecial portion of the whorl shows that they belong to the same whorl as the carpels. There are two levels of aberrant floral structures in Philodendron. The first one is represented by the presence of atypical bisexual flowers, which are intermediates between typical female flowers and typical sterile male flowers. The second one is the presence of intermediate structures between typical carpels and typical staminodes on a single atypical bisexual flower. The atypical bisexual flowers of P. squamiferum and P. pedatum are believed to be a case of Homeosis where carpels have been replaced by sterile stamens on the same whorl. A quantitative analysis indicates that in both species, on average, one staminode replaces one carpel. a 2002 Annals of Botany Company
-
developmental morphology of normal and atypical flowers of philodendron insigne araceae a new case of Homeosis
Botany, 2002Co-Authors: Denis Barabe, Christian R Lacroix, Bernard Le JeuneAbstract:The early stages of development of the inflorescence of Philodendron insigne were examined using scanning electron microscopy. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. The male flowers have three to five stamens. The female flowers have a multilocular ovary consisting of three to five locules. A transition zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is located between the male and female floral zones. Generally, the portion of the bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops one or two carpels. In P. insigne, the incomplete separation of staminodes from the gynoecial portion of the whorl shows that the staminodes and carpels belong to the same whorl. The atypical bisexual flowers of P. insigne are believed to be a case of Homeosis where carpels have been replaced by sterile stamens on the same...
Denis Barabe - One of the best experts on this subject based on the ideXlab platform.
-
quantitative developmental analysis of homeotic changes in the inflorescence of philodendron araceae
Annals of Botany, 2008Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:† Background and Aims The inflorescence of Philodendron constitutes an interesting morphological model to analyse the phenomenon of Homeosis quantitatively at the floral level. The specific goals of this study were (1) to characterize and quantify the range of homeotic transformation in Philodendron billietiae, and (2) to test the hypothesis that the nature of flowers surrounding atypical bisexual flowers (ABFs) channel the morphological potentialities of atypical bisexual flowers. † Methods Inflorescences of P. billietiae at different stages of development were observed using SEM. The number of appendices in male, female and sterile flowers were counted on 11 young inflorescences (5 – 6 flowers per inflorescence). The number of staminodes and carpels on ABFs were counted on 19 inflorescences (n ¼ 143). These data were used for regression and ANOVA analyses. † Results There was an average of 4.1 stamens per male flower, 9.8 carpels per female flower and 6.8 staminodes per sterile male flower. There was an average of 7.3 floral appendices per atypical flower. Staminodes and carpels are inserted on the same whorl in ABFs. A negative exponential relationship was found between the average number of staminodes and the number of carpels in ABFs. If only the ABFs consisting of less than six carpels are considered, there is a linear relationship between the number of carpels and the average number of staminodes. The value of the slope of the regression equation indicates that on average, in P. billietiae ,1 .36 carpels are replaced by one staminode. † Conclusions In P. billietiae, the number of appendages in female flowers imposes a constraint on the maximum total number of appendages (carpels and staminodes) that can develop on ABFs. The quantitative analyses indicate that the average number of different types of floral appendages on an ABF and the number of organs involved in a homeotic transformation are two independent phenomena.
-
the game of numbers in homeotic flowers of philodendron araceae
Botany, 2004Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:In Philodendron, pistillate flowers are initiated on the proximal portion of the inflorescence and staminate flowers are initiated on the distal portion. Between the staminate and pistillate flowers, there is a transition zone con- sisting of sterile male flowers adjacent to the male zone and a row of atypical bisexual flowers between the sterile male zone and the female zone. The portion of the atypical bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops into an incomplete gynoecium with few carpels. The atypical bisexual flowers of Philodendron are believed to be a case of Homeosis where carpels are replaced by sterile stamens on the same whorl. In Philodendron melinonii Brongniart ex Regel, Philodendron pedatum (Hooker) Kunth, Philodendron squamiferum Poeppig., and Philodendron solimoesense A.C. Smith, there is a significant quantitative relationship be- tween the number of carpels and the number of staminodes involved in the homeotic transformation in atypical bisex- ual flowers. On the other hand, such a significant correlation does not exist in Philodendron fragrantissimum (Hooker) Kunth and Philodendron insigne Schott, and Philodendron callosum K. Krause. There is a one to one organ replace- ment in homeotic flowers in both P. pedatum and P. squamiferum whereas, in P. solimoesense, an average of 2.56 staminodes replace one carpel. The average number of organs developing on an atypical bisexual flower and the num- ber of organs involved in a homeotic transformation appear to be two independent phenomena. The number of carpels in female flowers is correlated with the maximum total number of appendages (carpels and staminodes) that can de- velop in atypical bisexual flowers. Resume : Chez les Philodendron, les fleurs pistillees sont inserees dans la partie inferieure de l'inflorescence et les fleurs staminees dans la partie superieure. Entre la zone femelle et la zone mâle, se trouve une zone intermediaire formee de fleurs steriles mâles. Une rangee de fleurs bisexuees atypiques est presente entre la zone sterile et la zone femelle. La partie des fleurs bisexuees atypiques, placee du cote de la zone sterile, est formee de staminodes, et la partie situee du cote des fleurs femelles se developpe en un gynecee incomplet. Les fleurs bisexuees atypiques des Phi- lodendron presentent un cas d'Homeosis ou les carpelles sont remplaces par des staminodes sur un meme verticille. Chez les Philodendron melinonii Brongniart ex Regel, Philodendron pedatum (Hooker) Kunth, Philodendron squamife- rum Poeppig et Philodendron solimoesense A.C. Smith, il existe une relation quantitative significative entre le nombre de carpelles et le nombre de staminodes impliques dans une transformation homeotique, chez les fleurs bisexuees atypi- ques. On ne retrouve pas cette correlation significative chez les Philodendron fragrantissimum (Hooker) Kunth, Philo- dendron insigne Schott, et Philodendron callosum K. Krause. En moyenne, chez les P. pedatum ,e tP. squamiferum ,u n staminode remplace un carpelle, alors que chez le P. solimoesence 2,56 staminodes remplacent un carpelle. Le nombre moyen d'organes se developpant dans les fleurs bisexuees atypiques et le nombre d'organes impliques dans une trans- formation homeotique semblent provenir de deux phenomenes independants. Le nombre de carpelles presents dans les fleurs femelles est correle avec le nombre maximum d'appendices (carpelles et staminodes) pouvant se former dans les fleurs bisexuees atypiques. Mots cles : developpement, inflorescence, gradient, position, information.
-
study of Homeosis in the flower of philodendron araceae a qualitative and quantitative approach
Annals of Botany, 2002Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:This study deals specifically with floral organogenesis and the development of the inflorescence of Philodendron squamiferum and P. pedatum. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. An intermediate zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is also present. This zone is located between the sterile male and female floral zones. In general, the portion of bisexual flowers facing the male zone forms staminodes, and the portion facing the female zone develops an incomplete gynoecium with few carpels. The incomplete separation of some staminodes from the gynoecial portion of the whorl shows that they belong to the same whorl as the carpels. There are two levels of aberrant floral structures in Philodendron. The first one is represented by the presence of atypical bisexual flowers, which are intermediates between typical female flowers and typical sterile male flowers. The second one is the presence of intermediate structures between typical carpels and typical staminodes on a single atypical bisexual flower. The atypical bisexual flowers of P. squamiferum and P. pedatum are believed to be a case of Homeosis where carpels have been replaced by sterile stamens on the same whorl. A quantitative analysis indicates that in both species, on average, one staminode replaces one carpel. a 2002 Annals of Botany Company
-
developmental morphology of normal and atypical flowers of philodendron insigne araceae a new case of Homeosis
Botany, 2002Co-Authors: Denis Barabe, Christian R Lacroix, Bernard Le JeuneAbstract:The early stages of development of the inflorescence of Philodendron insigne were examined using scanning electron microscopy. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. The male flowers have three to five stamens. The female flowers have a multilocular ovary consisting of three to five locules. A transition zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is located between the male and female floral zones. Generally, the portion of the bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops one or two carpels. In P. insigne, the incomplete separation of staminodes from the gynoecial portion of the whorl shows that the staminodes and carpels belong to the same whorl. The atypical bisexual flowers of P. insigne are believed to be a case of Homeosis where carpels have been replaced by sterile stamens on the same...
-
NOTEAspects of floral development in Caladium bicolor (Araceae)
Canadian Journal of Botany, 2002Co-Authors: Denis Barabe, Christian LacroixAbstract:In the spadix of Caladium, there is a clearly recognizable intermediate zone consisting of sterile male flowers. The transition between the female zone and the male sterile zone is more or less abrupt. During the early stages of development of the inflorescence, a few atypical bisexual flowers between the female zone and the male sterile zone are recognizable. These atypical flowers display a variety of forms. However, in all cases, the staminate portion of the flower is located near the male zone and the gynoecial portion near the female zone. The undeveloped synandroidral portion and the rudimentary gynoecium belong to the same meristematic unit and can be viewed as a single whorl. The early stages of development of atypical bisexual flowers in Caladium and Philodendron are relatively similar and therefore represent an intermediate form between female and male sterile flowers.Key words: inflorescence, Homeosis, gradient, flower.
Christian Lacroix - One of the best experts on this subject based on the ideXlab platform.
-
quantitative developmental analysis of homeotic changes in the inflorescence of philodendron araceae
Annals of Botany, 2008Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:† Background and Aims The inflorescence of Philodendron constitutes an interesting morphological model to analyse the phenomenon of Homeosis quantitatively at the floral level. The specific goals of this study were (1) to characterize and quantify the range of homeotic transformation in Philodendron billietiae, and (2) to test the hypothesis that the nature of flowers surrounding atypical bisexual flowers (ABFs) channel the morphological potentialities of atypical bisexual flowers. † Methods Inflorescences of P. billietiae at different stages of development were observed using SEM. The number of appendices in male, female and sterile flowers were counted on 11 young inflorescences (5 – 6 flowers per inflorescence). The number of staminodes and carpels on ABFs were counted on 19 inflorescences (n ¼ 143). These data were used for regression and ANOVA analyses. † Results There was an average of 4.1 stamens per male flower, 9.8 carpels per female flower and 6.8 staminodes per sterile male flower. There was an average of 7.3 floral appendices per atypical flower. Staminodes and carpels are inserted on the same whorl in ABFs. A negative exponential relationship was found between the average number of staminodes and the number of carpels in ABFs. If only the ABFs consisting of less than six carpels are considered, there is a linear relationship between the number of carpels and the average number of staminodes. The value of the slope of the regression equation indicates that on average, in P. billietiae ,1 .36 carpels are replaced by one staminode. † Conclusions In P. billietiae, the number of appendages in female flowers imposes a constraint on the maximum total number of appendages (carpels and staminodes) that can develop on ABFs. The quantitative analyses indicate that the average number of different types of floral appendages on an ABF and the number of organs involved in a homeotic transformation are two independent phenomena.
-
the game of numbers in homeotic flowers of philodendron araceae
Botany, 2004Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:In Philodendron, pistillate flowers are initiated on the proximal portion of the inflorescence and staminate flowers are initiated on the distal portion. Between the staminate and pistillate flowers, there is a transition zone con- sisting of sterile male flowers adjacent to the male zone and a row of atypical bisexual flowers between the sterile male zone and the female zone. The portion of the atypical bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops into an incomplete gynoecium with few carpels. The atypical bisexual flowers of Philodendron are believed to be a case of Homeosis where carpels are replaced by sterile stamens on the same whorl. In Philodendron melinonii Brongniart ex Regel, Philodendron pedatum (Hooker) Kunth, Philodendron squamiferum Poeppig., and Philodendron solimoesense A.C. Smith, there is a significant quantitative relationship be- tween the number of carpels and the number of staminodes involved in the homeotic transformation in atypical bisex- ual flowers. On the other hand, such a significant correlation does not exist in Philodendron fragrantissimum (Hooker) Kunth and Philodendron insigne Schott, and Philodendron callosum K. Krause. There is a one to one organ replace- ment in homeotic flowers in both P. pedatum and P. squamiferum whereas, in P. solimoesense, an average of 2.56 staminodes replace one carpel. The average number of organs developing on an atypical bisexual flower and the num- ber of organs involved in a homeotic transformation appear to be two independent phenomena. The number of carpels in female flowers is correlated with the maximum total number of appendages (carpels and staminodes) that can de- velop in atypical bisexual flowers. Resume : Chez les Philodendron, les fleurs pistillees sont inserees dans la partie inferieure de l'inflorescence et les fleurs staminees dans la partie superieure. Entre la zone femelle et la zone mâle, se trouve une zone intermediaire formee de fleurs steriles mâles. Une rangee de fleurs bisexuees atypiques est presente entre la zone sterile et la zone femelle. La partie des fleurs bisexuees atypiques, placee du cote de la zone sterile, est formee de staminodes, et la partie situee du cote des fleurs femelles se developpe en un gynecee incomplet. Les fleurs bisexuees atypiques des Phi- lodendron presentent un cas d'Homeosis ou les carpelles sont remplaces par des staminodes sur un meme verticille. Chez les Philodendron melinonii Brongniart ex Regel, Philodendron pedatum (Hooker) Kunth, Philodendron squamife- rum Poeppig et Philodendron solimoesense A.C. Smith, il existe une relation quantitative significative entre le nombre de carpelles et le nombre de staminodes impliques dans une transformation homeotique, chez les fleurs bisexuees atypi- ques. On ne retrouve pas cette correlation significative chez les Philodendron fragrantissimum (Hooker) Kunth, Philo- dendron insigne Schott, et Philodendron callosum K. Krause. En moyenne, chez les P. pedatum ,e tP. squamiferum ,u n staminode remplace un carpelle, alors que chez le P. solimoesence 2,56 staminodes remplacent un carpelle. Le nombre moyen d'organes se developpant dans les fleurs bisexuees atypiques et le nombre d'organes impliques dans une trans- formation homeotique semblent provenir de deux phenomenes independants. Le nombre de carpelles presents dans les fleurs femelles est correle avec le nombre maximum d'appendices (carpelles et staminodes) pouvant se former dans les fleurs bisexuees atypiques. Mots cles : developpement, inflorescence, gradient, position, information.
-
study of Homeosis in the flower of philodendron araceae a qualitative and quantitative approach
Annals of Botany, 2002Co-Authors: Denis Barabe, Christian Lacroix, Bernard Le JeuneAbstract:This study deals specifically with floral organogenesis and the development of the inflorescence of Philodendron squamiferum and P. pedatum. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. An intermediate zone consisting of sterile male flowers and atypical bisexual flowers with fused or free carpels and staminodes is also present. This zone is located between the sterile male and female floral zones. In general, the portion of bisexual flowers facing the male zone forms staminodes, and the portion facing the female zone develops an incomplete gynoecium with few carpels. The incomplete separation of some staminodes from the gynoecial portion of the whorl shows that they belong to the same whorl as the carpels. There are two levels of aberrant floral structures in Philodendron. The first one is represented by the presence of atypical bisexual flowers, which are intermediates between typical female flowers and typical sterile male flowers. The second one is the presence of intermediate structures between typical carpels and typical staminodes on a single atypical bisexual flower. The atypical bisexual flowers of P. squamiferum and P. pedatum are believed to be a case of Homeosis where carpels have been replaced by sterile stamens on the same whorl. A quantitative analysis indicates that in both species, on average, one staminode replaces one carpel. a 2002 Annals of Botany Company
-
NOTEAspects of floral development in Caladium bicolor (Araceae)
Canadian Journal of Botany, 2002Co-Authors: Denis Barabe, Christian LacroixAbstract:In the spadix of Caladium, there is a clearly recognizable intermediate zone consisting of sterile male flowers. The transition between the female zone and the male sterile zone is more or less abrupt. During the early stages of development of the inflorescence, a few atypical bisexual flowers between the female zone and the male sterile zone are recognizable. These atypical flowers display a variety of forms. However, in all cases, the staminate portion of the flower is located near the male zone and the gynoecial portion near the female zone. The undeveloped synandroidral portion and the rudimentary gynoecium belong to the same meristematic unit and can be viewed as a single whorl. The early stages of development of atypical bisexual flowers in Caladium and Philodendron are relatively similar and therefore represent an intermediate form between female and male sterile flowers.Key words: inflorescence, Homeosis, gradient, flower.
-
Homeosis in araceae flowers the case of philodendron melinonii
Annals of Botany, 2000Co-Authors: Denis Barabe, Christian LacroixAbstract:Abstract The early stages of development of the inflorescence of Philodendron melinonii were examined using scanning electron microscopy. Pistillate flowers are initiated on the lower portion of the inflorescence and staminate flowers are initiated on the distal portion. The male flowers have four to five stamens. The female flowers have a multilocular ovary consisting of four to six locules. A transition zone consisting of sterile male flowers and bisexual flowers with fused or free carpels and staminodes is also present on the inflorescences. This zone is located between the male and female flower zones. Generally, the portion of the bisexual flower facing the male zone forms stamens, and the portion facing the female zone develops an incomplete gynoecium with few carpels. In P. melinonii, the incomplete separation of staminodes from the gynoecial portion of the whorl shows that the staminodes and carpels belong to the same whorl. The bisexual flowers of P. melinonii are believed to be a case of Homeosis where carpels have been replaced by sterile stamens on the same whorl. At the level of the inflorescence, pistillate and staminate flowers are inserted on the same contact parastichies along the inflorescence; there is no discontinuity between the female zone, the bisexual zone, and the male zone. The presence of bisexual flowers is believed to correspond to a morphogenetic gradient at the level of the inflorescence as a whole.
Pascal Dolle - One of the best experts on this subject based on the ideXlab platform.
-
axial skeleton Homeosis and forelimb malformations in hoxd 11 mutant mice
Proceedings of the National Academy of Sciences of the United States of America, 1995Co-Authors: Bertrand Favier, Le M Meur, Pierre Chambon, Pascal DolleAbstract:The Hoxd-11 gene was disrupted by homologous recombination in embryonic stem cells. We found that Hoxd-11-/- mutant mice are viable and display homeotic transformations of their sacral vertebrae, while their forelimbs present abnormalities of some metacarpals and of the first row of carpal bones. These results are discussed in the light of current models of tetrapod axial skeleton and limb patterning.
Mario R Capecchi - One of the best experts on this subject based on the ideXlab platform.
-
axial Homeosis and appendicular skeleton defects in mice with a targeted disruption of hoxd 11
Development, 1994Co-Authors: Allan Peter Davis, Mario R CapecchiAbstract:Using gene targeting, we have created mice with a disruption in the homeobox-containing gene hoxd-11. Homozygous mutants are viable and the only outwardly apparent abnormality is male infertility. Skeletons of mutant mice show a homeotic transformation that repatterns the sacrum such that each vertebra adopts the structure of the next most anterior vertebra. Defects are also seen in the bones of the limb, including regional malformations at the distal end of the forelimb affecting the length and structure of phalanges and metacarpals, inappropriate fusions between wrist bones, and defects at the most distal end in the long bones of the radius and ulna. The phenotypes show both incomplete penetrance and variable expressivity. In contrast to the defects observed in the vertebral column, the phenotypes in the appendicular skeleton do not resemble homeotic transformations, but rather regional malformations in the shapes, length and segmentation of bones. Our results are discussed in the context of two other recent gene targeting studies involving the paralogous gene hoxa-11 and another member of the Hox D locus, hoxd-13. The position of these limb deformities reflects the temporal and structural colinearity of the Hox genes, such that inactivation of 3′ genes has a more proximal phenotypic boundary (affecting both the zeugopod and autopod of the limb) than that of the more 5′ genes (affecting only the autopod). Taken together, these observations suggest an important role for Hox genes in controlling localized growth of those cells that contribute to forming the appendicular skeleton.