scholarly journals Sex-determining genes in the homosporous fern Ceratopteris

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1949-1958 ◽  
Author(s):  
J.A. Banks
Keyword(s):  
Sex Determination ◽  
Double Mutant ◽  
Single Gene ◽  
Regulatory Pathway ◽  
Male Development ◽  
Gene Mutant ◽  
Sex Type ◽  
Homosporous Fern ◽  
Mutant Phenotypes ◽  
Sporophyte Development

Haploid Ceratopteris gametophytes are either hermaphroditic or male. The determinate of sex type is the pheromone antheridiogen (ACE) which is secreted by the meristic hermaphrodite and promotes ameristic male development of sexually undetermined gametophytes. Several mutations effecting the sex of the haploid gametophyte have been isolated and are described. The hermaphroditic (her) mutants are insensitive to ACE and develop as meristic hermaphrodites. These mutations effect ameristic male development in the presence of ACE but have no effect on hermaphroditic development. While most her mutations also have no effect on diploid sporophyte development, some partially ACE-insensitive her mutations have profound effects on sporophyte development. The transformer (tra) mutation effects both meristem and archegonia formation and causes the gametophyte to be an ameristic male under conditions that promote hermaphroditic development. The feminization (fem) mutation effects antheridia development in both male and hermaphroditic gametophytes and causes the gametophyte to develop as a meristic female in the absence or presence of the pheromone. The her1 tra1 double mutant is male in the absence or presence of ACE, indicating that tra1 is epistatic to her1. The phenotypes of her1, tra1 and fem1 single gene mutant phenotypes and the her1 tra1 double mutant phenotype are used to deduce a model suggesting how the products of these genes might interact in a regulatory pathway to control sex determination.

Antheridiogen concentration and spore size predict gametophyte size in Ceratopteris richardii

Botany ◽  
2012 ◽  
Vol 90 (3) ◽  
pp. 175-179 ◽  
Author(s):  
Mike Ganger ◽  
Tiffany Sturey
Keyword(s):  
Sex Determination ◽  
Environmental Sex Determination ◽  
Wild Type ◽  
Ceratopteris Richardii ◽  
Spore Size ◽  
Male Development ◽  
Homosporous Fern ◽  
Type C ◽  
Slow Growing ◽  
Genetic Mutants

In many plants females invest more in reproduction than males. In organisms that exhibit environmental sex determination, individuals in low-quality environments or who are slow growing are expected to develop into males. The gametophytes of Ceratopteris richardii Brongn., a homosporous fern, may develop as males or hermaphrodites. Hermaphrodites secrete a pheromone called antheridiogen that induces undifferentiated spores to develop as males. Given that induction is not 100% in the presence of antheridiogen, it is hypothesized that resources may alter C. richardii gender decisions. An experiment was undertaken to determine (i) whether spore size predicts gender, (ii) whether spore size predicts gametophyte size, (iii) whether antheridiogen negatively affects the growth of C. richardii, and (iv) whether wild-type C. richardii and him1 mutants (genetic mutants disposed to male development regardless of antheridiogen presence) behave similarly in their response to antheridiogen. Spore size was not predictive of gender but was positively related to both male and hermaphrodite gametophyte size. Antheridiogen was found to slow the growth of male and hermaphrodite gametophytes of the wild type and male gametophytes of the him1 mutant. These results are supportive of the idea that gender may be determined indirectly through antheridiogen’s effect on gametophyte growth.

scholarly journals The TRANSFORMER Genes of the Fern Ceratopteris Simultaneously Promote Meristem and Archegonia Development and Repress Antheridia Development in the Developing Gametophyte

Genetics ◽  
1997 ◽  
Vol 147 (4) ◽  
pp. 1885-1897 ◽  
Author(s):  
Jo Ann Banks
Keyword(s):  
Sex Determination ◽  
Sex Expression ◽  
The Other ◽  
Female Development ◽  
Epistatic Interactions ◽  
Male Development ◽  
Sporophyte Development

Abstract The sex of the haploid gametophyte of the fern Ceratopteris is determined by the presence or absence of the pheromone antheridiogen, which, when present, promotes male development and represses female development of the gametophyte. Several genes involved in sex determination in Ceratopteris have been identified by mutation. In this study, the epistatic interactions among new and previously described sex-determining mutants have been characterized. These results show that sex expression is regulated by two sets of genes defined by the FEM1 and TRA loci. Each promotes the expression of either male or female traits and simultaneously represses the expression of the other. A model describing how antheridiogen regulates the expression of these genes and the sex of the gametophyte is described. The observation that some gametophytic sexdetermining mutants have phenotypic effects on the spore phyte plant indicates that sex determination in the Ceratopteris gametophyte is regulated by a mechanism that also regulates sporophyte development.

scholarly journals Genetic Interactions Among Sex-Determining Genes in the Fern Ceratopteris richardii

Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 973-985
Author(s):  
James R Eberle ◽  
Jo Ann Banks
Keyword(s):  
Linkage Analysis ◽  
Sex Determination ◽  
Genetic Interactions ◽  
Ceratopteris Richardii ◽  
Male Development ◽  
Sex Type

Abstract Haploid gametophytes of the fern Ceratopteris are either male or hermaphroditic. The determinant of sex type is the pheromone antheridiogen, which is secreted by the hermaphrodite and directs male development of young, sexually undetermined gametophytes. Three phenotypic classes of mutations that affect sex-determination were previously isolated and include the hermaphroditic (her), the transformer (tra) and feminization (fem) mutations. In the present study, linkage analysis and tests of epistasis among the different mutants have been performed to assess the possible interactions among these genes. The results indicate that sex determination in Ceratopteris involves at least seven interacting genes in addition to antheridiogen, the primary sex-determining signal. Two models describing how antheridiogen may influence the activity states of these genes and the sex of the gametophyte are discussed.

Two homologous regulatory genes, lin-12 and glp-1, have overlapping functions

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 231-240 ◽  
Author(s):  
E.J. Lambie ◽  
J. Kimble
Keyword(s):  
Gene Expression ◽  
Double Mutant ◽  
Transmembrane Proteins ◽  
Cell Interactions ◽  
Loss Of Function ◽  
Cell Fates ◽  
Single Mutant ◽  
C Elegans ◽  
Homologous Genes ◽  
Mutant Phenotypes

Two homologous genes, lin-12 and glp-1, encode transmembrane proteins required for regulatory cell interactions during C. elegans development. Based on their single mutant phenotypes, each gene has been thought to govern a distinct set of cell fates. We show here that lin-12 and glp-1 are functionally redundant during embryogenesis: Unlike either single mutant, the lin-12 glp-1 double mutant dies soon after hatching. Numerous cellular defects can be observed in these Lag (for lin-12 and glp-1) double mutants. Furthermore, we have identified two genes, lag-1 and lag-2, that appear to be required for both lin-12 and glp-1-mediated cell interactions. Strong loss-of-function lag mutants are phenotypically indistinguishable from the lin-12 glp-1 double; weak lag mutants have phenotypes typical of lin-12 and glp-1 single mutants. We speculate that the lin-12 and glp-1 proteins are biochemically interchangeable and that their divergent roles in development may rely largely on differences in gene expression.

Ontogenetic study of the fusion of floral organs in the normal and "solanifolia" mutant of tomato (Lycopersicon esculentum)

1987 ◽  
Vol 65 (2) ◽  
pp. 215-221 ◽  
Author(s):  
K. N. Chandra Sekhar ◽  
V. K. Sawhney
Keyword(s):  
Lycopersicon Esculentum ◽  
Single Gene ◽  
Corolla Tube ◽  
Lateral Growth ◽  
Floral Organs ◽  
Lack Of Fusion ◽  
Organ Type ◽  
Gene Mutant ◽  
Ontogenetic Study ◽  
Single Ovary

A comparative study on the ontogeny of the fusion of floral organs of the normal (cv. Pearson) and a single-gene mutant, "solanifolia" (sf/sf), of tomato (Lycopersicon esculentum Mill.) was conducted. In the normal, floral organs were laterally fused, although the degree and the region of fusion varied in each organ type. In the mutant, the various organs either did not fuse or, if they did, were individually recognizable. The sepals and petals of mutant flowers, unlike those of the normal, did not form a calyx cup and a corolla tube, respectively, and this was related to the limited lateral growth of mutant primordia and the absence of growth in the interprimordial region. Also, petal primordia of the mutant were narrower in width at inception. The stamens of normal flowers were fused by interweaving rows of lateral and adaxial hairs on the anthers. The mutant stamens produced lateral and adaxial hairs, yet they were free. The nonfusion of mutant stamens was related to the smaller primordium widths, greater distance between the primordia, and the larger apex diameter at the time of stamen initiation. The gynoecium of normal flowers consisted of a single ovary, style, and stigma formed by the fusion of carpel primordia. In the mutant, the gynoecium consisted of several carpels, laterally adhered to each other, and each had a recognizable style and stigma. The lack of fusion of mutant carpels was attributed to the larger apex diameter of the mutant during carpel initiation.

Genetic and morphological analysis of floral homeotic mutants tepal-like bract and fagopyrum apetala of Fagopyrum esculentum

Botany ◽  
2008 ◽  
Vol 86 (4) ◽  
pp. 367-375 ◽  
Author(s):  
Maria D. Logacheva ◽  
Ivan N. Fesenko ◽  
Aleksey N. Fesenko ◽  
Aleksey A. Penin
Keyword(s):  
Plant Species ◽  
Morphological Analysis ◽  
Morphological Evolution ◽  
Single Gene ◽  
Gene Mutations ◽  
Fagopyrum Esculentum ◽  
Wide Range ◽  
Fagopyrum Esculentum Moench ◽  
Mutant Phenotypes ◽  
Floral Homeotic

The studies on floral homeotic mutants of the model plant species Arabidopsis thaliana (L.) Heynh. and Antirrhinum majus L. have clarified many important aspects of the genetic control of flower development. However, the details of this process can vary in species representing different lineages of flowering plants. The studies on floral homeotic mutants of nonmodel plant species may significantly improve the understanding of the mechanisms of morphological evolution of flowers. We report here the results of the genetic and morphological analysis of two floral homeotic mutants of common buckwheat ( Fagopyrum esculentum Moench.). The mutant, tepal-like bract (tlb), is characterized by the transformation of bracts into petaloid organs, whereas fagopyrum apetala (fap), has a carpelloid perianth. Both mutant phenotypes are caused by a single recessive nuclear mutation. The double mutant fap tlb combines the features of tlb and fap. Our results show that single gene mutations are sufficient to convert the buckwheat bract into a tepal and to confer carpel identity on first whorl organs. These results are consistent with the premise that variations on the ABC model can be used to explain a wide range of floral architectures.

Implications of Double Mutant Phenotypes

1990 ◽  
Vol 605 (1 Myelination a) ◽  
pp. 215-229 ◽  
Author(s):  
SUSAN BILLINGS-GAGLIARDI ◽  
MERRILL K. WOLF
Keyword(s):  
Double Mutant ◽  
Mutant Phenotypes

scholarly journals rosR, a Determinant of Nodulation Competitiveness in Rhizobium etli

1997 ◽  
Vol 10 (2) ◽  
pp. 180-186 ◽  
Author(s):  
Mark A. Bittinger ◽  
Jocelyn L. Milner ◽  
Barry J. Saville ◽  
Jo Handelsman
Keyword(s):  
Cell Surface ◽  
Rhizobium Meliloti ◽  
Single Gene ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Competitive Growth ◽  
Rhizobium Etli ◽  
Reading Frame ◽  
Nodulation Competitiveness ◽  
Mutant Phenotypes

We previously described a Tn5 mutant of Rhizobium etli strain CE3, designated CE3003, that is decreased in nodulation competitiveness, reduced in competitive growth in the rhizosphere, and has a hydrophobic cell surface (R. S. Araujo, E. A. Robleto, and J. Handelsman, Appl. Environ. Microbiol., 60:1430–1436, 1994). To determine the molecular basis for the mutant phenotypes, we identified a 1.2-kb fragment of DNA derived from the parent that restored the wild-type phenotypes to the mutant. DNA sequence analysis indicated that this 1.2-kb fragment contained a single open reading frame that we designated rosR. The Tn5 insertion in CE3003 was within rosR. We constructed a derivative of CE3 that contained a deletion in rosR, and this mutant was phenotypically indistinguishable from CE3003 in cell surface and competitive characteristics. Based on the nucleotide sequence, the deduced RosR amino acid sequence is 80% identical to that of the Ros protein from Agrobacterium tumefaciens and the MucR protein from Rhizobium meliloti. Both Ros and MucR are transcriptional repressors that contain a putative zinc-finger DNA-binding domain. This study defines a gene, rosR, that is homologous to a family of transcriptional regulators and contributes to nodulation competitiveness of R. etli. Moreover, we established that a single gene affects nodulation competitiveness, competitive growth in the rhizosphere, and cell surface hydrophobicity.

scholarly journals Phenotypic analysis of catastrophic childhood epilepsy genes: The Epilepsy Zebrafish Project

2021 ◽  
Author(s):  
Aliesha Griffin ◽  
Colleen Carpenter ◽  
Jing Liu ◽  
Rosalia Paterno ◽  
Brian Grone ◽  
...  
Keyword(s):  
Neurological Disorders ◽  
Classification Scheme ◽  
Single Gene ◽  
Field Potential ◽  
Phenotypic Analysis ◽  
Electrographic Seizure ◽  
Starting Point ◽  
Gene Mutant ◽  
Epilepsy Classification ◽  
Neuroscience Community

AbstractGenetic engineering techniques have contributed to the now widespread use of zebrafish to investigate gene function, but zebrafish-based human disease studies, and particularly for neurological disorders, are limited. Here we used CRISPR-Cas9 to generate 40 single-gene mutant zebrafish lines representing catastrophic childhood epilepsies. We evaluated larval phenotypes using electrophysiological, behavioral, neuro-anatomical, survival and pharmacological assays. Phenotypes with unprovoked electrographic seizure activity (i.e., epilepsy) were identified in zebrafish lines for 8 genes; ARX, EEF1A, GABRB3, GRIN1, PNPO, SCN1A, STRADA and STXBP1. A unifying epilepsy classification scheme was developed based on local field potential recordings and blinded scoring from ~3300 larvae. We also created an open-source database containing sequencing information, survival curves, behavioral profiles and representative electrophysiology data. We offer all zebrafish lines as a resource to the neuroscience community and envision them as a starting point for further functional analysis and/or identification of new therapies.

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