HYBRIDIZATION EXPERIMENTS IN RHODEINE FISHES (CYPRINIDAE, TELEOSTEI): THE INTERGENERIC HYBRIDS OF ACHEILOGNATHUS LANCEOLATA ♂ × ACANTHORHODEUS ATREMIUS ♀ AND TANAKIA TANAGO ♂ × ACHEILOGNATHUS RHOMBEA ♀

1960 ◽  
Vol 38 (6) ◽  
pp. 1171-1173 ◽  
Author(s):  
J. J. Duyvené de Wit
Keyword(s):  
Embryonic Development ◽  
Genetic Factor ◽  
Parental Species ◽  
Intergeneric Hybrids ◽  
Free Swimming ◽  
Phylogenetic Relations ◽  
Male Phenotype

In order to study the phylogenetic relations between rhodeine species a number of interspecific and intergeneric crossings have been performed. This communication deals with the intergeneric hybrids obtained from the combinations Acheilognathus lanceolata ♂ × Acanthorhodeus atremius ♀ and Tanakia tanago ♂ × Acheilognathus rhombea ♀.From the first combination adult hybrids have been obtained which were intermediate between both parental species and showed a male phenotype. The second combination produced larvae, but a deficient yolk supply prevented them from reaching the free-swimming stage.Experimental evidence is presented for the occurrence of a dominant genetic factor in A. rhombea males, which controls the duration of embryonic development in this and other bitterling species.

Intergeneric hybrids between Thinopyrum and Psathyrostachys (Triticeae)

Genome ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 845-849 ◽  
Author(s):  
Richard R.-C. Wang
Keyword(s):  
Genome Analysis ◽  
Parental Species ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Green Leaves ◽  
Psathyrostachys Juncea ◽  
Basic Genome ◽  
Chromosome Associations ◽  
Thinopyrum Elongatum ◽  
First Time

Intergeneric hybrids were synthesized for the first time from the diploid crosses Thinopyrum elongatum (JeJe) × Psathyrostachys juncea (NjNj), T. elongatum × P. fragilis (NfNf), T. bessarabicum (JbJb) × P. huashanica (NhNh), and T. bessarabicum × P. juncea, as well as from a cross between the amphidiploid of T. bessarabicum × T. elongatum (JbJbJeJe) and P. juncea. Spikes of these hybrids are morphologically intermediate between those of the parental species. Double spikelets occurred occasionally at central nodes of the spikes. Glaucous blue leaves appeared in the F1 only in the cross T. bessarabicum × P. huashanica, suggesting that the gene(s) for glaucous blue leaves in T. bessarabicum is (are) recessive to a gene(s) for green leaves in P. juncea but is (are) dominant to that for yellowish green leaves in P. huashanica. Meiotic pairing at metaphase I in these diploid (JN) and triploid (JJN) hybrids revealed a very low level of homology between the basic J and N genome. Therefore, the J and N genomes are nonhomologous and justifiably represented by different genome symbols. The triploid hybrids exhibited a pattern of chromosome associations that substantiated the earlier conclusion that the genomes in T. bessarabicum and T. elongatum are two versions of a basic genome (J). These hybrids will be useful in genome analysis, forming new Leymus species with the J and N genomes and broadening the diversity in the genus Pascopyrum with the SHJN genomes.Key words: hybrid, Thinopyrum, Psathyrostachys, genome.

Embryonic and larval development and segment formation in Ibla quadrivalivis Cuv. (Cirripedia).

1965 ◽  
Vol 13 (1) ◽  
pp. 1 ◽  
Author(s):  
DT Anderson
Keyword(s):  
Embryonic Development ◽  
Larval Development ◽  
Larval Growth ◽  
Growth Zone ◽  
Larval Survival ◽  
Direct Development ◽  
Gut Development ◽  
Free Swimming ◽  
Phylogenetic Affinity ◽  
Embryonic And Larval Development

Embryonic development in I. quadrivalvis follows the typical cirripede pattern except for modifications of cleavage and of development of the gut, associated with a large yolky egg. The nauplius is free-swimming but lecithotrophic. It does not grow, and moults irregularly. The development of cypris features begins precociously and the second half of naupliar life is demersal. The cypris stage is unmodified. Settling was not observed. The maxillary segments develop as a delayed continuation of the naupliar segmental sequence, the thoracic segments from a growth zone of seven ectoteloblasts and eight mesoteloblasts. Each row of eight cells budded from the mesoteloblasts develops into the paired somites of a segment. The midgut develops independently of the yolk cells. In cirripedes, increased yolk results in modification of cleavage and gut development but otherwise has little influence on embryonic development. Larval modifications associated with lecithotrophy promote direct development of the cypris but do not include modification of the cypris. Irregularity of moulting is associated with lack of larval growth. Relative brood sizes suggest that increased yolk in cirripedes offers advantages in larval survival. Post-naupliar segment formation in cirripedes resembles in detail that of Malacostraca, indicating a possible phylogenetic affinity between Malacostraca and Maxillopoda which can be tested by further studies on segment formation in non- Malacostraca.

First intergeneric hybrids (Psilanthus ebracteolatus Hiern x Coffea arabica L.) in coffee trees

1998 ◽  
Vol 76 (3) ◽  
pp. 542-546 ◽  
Author(s):  
E Couturon ◽  
P Lashermes ◽  
A Charrier
Keyword(s):  
Coffea Arabica ◽  
Parental Species ◽  
Morphological Characteristics ◽  
Intergeneric Hybrids ◽  
Molecular Methods ◽  
Wide Cross ◽  
Coffea Species ◽  
The Mean ◽  
Tetraploid Level ◽  
Coffea Arabica L

Intergeneric hybrids between Psilanthus ebracteolatus (2n = 22) and Coffea arabica (2n = 44) were successfully produced by crossing at the tetraploid level. Although a total of 41 plants was obtained, only nine plants survived after 5 months growth in the nursery. Hybrid status was confirmed by means of cytological and molecular methods. For most of the morphological characteristics analyzed, hybrids appeared intermediate between the two parental species. The mean production of two surviving hybrids per 100 pollinated flowers as well as their fertility are comparable with those reported for intrageneric crosses between subgenera Coffea species, and do not support the present division of coffee trees into two genera. Both the capacity of C. arabica to hybridize with P. ebracteolatus and the fertility of hybrids produced appear high enough to envisage intergeneric gene transfers from P. ebracteolatus into C. arabica.Key words: coffee, fertility, hybridization, intergeneric, polyploid, wide cross.

scholarly journals Analysis of the Meiotic Segregation in Intergeneric Hybrids of Tilapias

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Etienne Bezault ◽  
Xavier Rognon ◽  
Frederic Clota ◽  
Karim Gharbi ◽  
Jean-Francois Baroiller ◽  
...  
Keyword(s):  
Parental Species ◽  
Genome Structure ◽  
Intergeneric Hybrids ◽  
Interspecific Hybridisation ◽  
Meiotic Segregation ◽  
Apparent Lack ◽  
Cichlid Species ◽  
In The Wild ◽  
Sarotherodon Melanotheron ◽  
Generation Hybrid

Tilapia species exhibit a large ecological diversity and an important propensity to interspecific hybridisation. This has been shown in the wild and used in aquaculture. However, despite its important evolutionary implications, few studies have focused on the analysis of hybrid genomes and their meiotic segregation. Intergeneric hybrids between Oreochromis niloticus and Sarotherodon melanotheron, two species highly differentiated genetically, ecologically, and behaviourally, were produced experimentally. The meiotic segregation of these hybrids was analysed in reciprocal second generation hybrid (F2) and backcross families and compared to the meiosis of both parental species, using a panel of 30 microsatellite markers. Hybrid meioses showed segregation in accordance to Mendelian expectations, independent from sex and the direction of crosses. In addition, we observed a conservation of linkage associations between markers, which suggests a relatively similar genome structure between the two parental species and the apparent lack of postzygotic incompatibility, despite their important divergence. These results provide genomics insights into the relative ease of hybridisation within cichlid species when prezygotic barriers are disrupted. Overall our results support the hypothesis that hybridisation may have played an important role in the evolution and diversification of cichlids.

scholarly journals A new t-complex embryonic lethal (tcl0) has arisen in the Thp chromosome of the mouse and is allelic to t0

1984 ◽  
Vol 43 (1) ◽  
pp. 27-33
Author(s):  
Edwin R. Sanchez ◽  
Craig Hammerberg
Keyword(s):  
Embryonic Development ◽  
Point Mutation ◽  
Genetic Factor ◽  
Single Gene ◽  
Lethal Factor ◽  
T Complex ◽  
Embryonic Lethal

SUMMARYComplement testing of a Thp line revealed a failure of survival of Thp/t0 embryos. The genetic factor responsible for this lethality maps between Brachyury (T) and tufted (tf) on the murine seventeenth chromosome. This lethal factor permits recombination between T and tf and does not affect the transmission of its seventeenth chromosome. Its effect upon embryonic development is similar to that of the t0 haplotype. It would appear to represent a point mutation of a single gene, t-complex lethal zero (tcl0).

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

Live Confocal Analysis of Fertilization and Early Development

2001 ◽  
Vol 7 (S2) ◽  
pp. 1012-1013
Author(s):  
Uyen Tram ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Real Time ◽  
Early Development ◽  
Fluorescent Probes ◽  
Primary Defect ◽  
Fluorescent Analysis ◽  
Dynamic Event ◽  
Enormous Amount ◽  
Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

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