Does the female seahorse still prefer her mating partner after a period of separation?

2021 ◽  
Author(s):  
Tingting Lin ◽  
Xin Liu ◽  
Dong Zhang
Keyword(s):  
Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Kathrin Schrick ◽  
Barbara Garvik ◽  
Leland H Hartwell

Abstract The mating process in yeast has two distinct aspects. One is the induction and activation of proteins required for cell fusion in response to a pheromone signal; the other is chemotropism, i.e., detection of a pheromone gradient and construction of a fusion site available to the signaling cell. To determine whether components of the signal transduction pathway necessary for transcriptional activation also play a role in chemotropism, we examined strains with null mutations in components of the signal transduction pathway for diploid formation, prezygote formation and the chemotropic process of mating partner discrimination when transcription was induced downstream of the mutation. Cells mutant for components of the mitogen-activated protein (MAP) kinase cascade (ste5, ste20, ste11, ste7 or fus3 kss1) formed diploids at a frequency 1% that of the wild-type control, but formed prezygotes as efficiently as the wild-type control and showed good mating partner discrimination, suggesting that the MAP kinase cascade is not essential for chemotropism. In contrast, cells mutant for the receptor (ste2) or the β or γ subunit (ste4 and stel8) of the G protein were extremely defective in both diploid and prezygote formation and discriminated poorly between signaling and nonsignaling mating partners, implying that these components are important for chemotropism.


Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 133-140
Author(s):  
Kazumi Inada ◽  
Yoshinori Morimoto ◽  
Toshihide Arima ◽  
Yukio Murata ◽  
Takashi Kamada

Abstract Sexual development in the mushroom Coprinus cinereus is under the control of the A and B mating-type loci, both of which must be different for a compatible, dikaryotic mycelium to form between two parents. The A genes, encoding proteins with homeodomain motifs, regulate conjugate division of the two nuclei from each mating partner and promote the formation of clamp connections. The latter are hyphal configurations required for the maintenance of the nuclear status in the dikaryotic phase of basidiomycetes. The B genes encode pheromones and pheromone receptors. They regulate the cellular fusions that complete clamp connections during growth, as well as the nuclear migration required for dikaryosis. The AmutBmut strain (326) of C. cinereus, in which both A- and B-regulated pathways are constitutively activated by mutations, produces, without mating, dikaryon-like, fertile hyphae with clamp connections. In this study we isolated and characterized clampless1-1 (clp1-1), a mutation that blocks clamp formation, an essential step in A-regulated sexual development, in the AmutBmut background. A genomic DNA fragment that rescues the clp1-1 mutation was identified by transformations. Sequencing of the genomic DNA, together with RACE experiments, identified an ORF interrupted by one intron, encoding a novel protein of 365 amino acids. The clp1-1 mutant allele carries a deletion of four nucleotides, which is predicted to cause elimination of codon 128 and frameshifts thereafter. The clp1 transcript was normally detected only in the presence of the A protein heterodimer formed when homokaryons with compatible A genes were mated. Forced expression of clp1 by promoter replacements induced clamp development without the need for a compatible A gene combination. These results indicate that expression of clp1 is necessary and sufficient for induction of the A-regulated pathway that leads to clamp development.


2021 ◽  
Vol 7 (2) ◽  
pp. 86
Author(s):  
Bilal Ökmen ◽  
Daniela Schwammbach ◽  
Guus Bakkeren ◽  
Ulla Neumann ◽  
Gunther Doehlemann

Obligate biotrophic fungal pathogens, such as Blumeria graminis and Puccinia graminis, are amongst the most devastating plant pathogens, causing dramatic yield losses in many economically important crops worldwide. However, a lack of reliable tools for the efficient genetic transformation has hampered studies into the molecular basis of their virulence or pathogenicity. In this study, we present the Ustilago hordei–barley pathosystem as a model to characterize effectors from different plant pathogenic fungi. We generate U. hordei solopathogenic strains, which form infectious filaments without the presence of a compatible mating partner. Solopathogenic strains are suitable for heterologous expression system for fungal virulence factors. A highly efficient Crispr/Cas9 gene editing system is made available for U. hordei. In addition, U. hordei infection structures during barley colonization are analyzed using transmission electron microscopy, showing that U. hordei forms intracellular infection structures sharing high similarity to haustoria formed by obligate rust and powdery mildew fungi. Thus, U. hordei has high potential as a fungal expression platform for functional studies of heterologous effector proteins in barley.


1993 ◽  
Vol 104 (2) ◽  
pp. 227-230
Author(s):  
U. Kues ◽  
L.A. Casselton

Having multiple mating types greatly improves the chances of meeting a compatible mating partner, particularly in an organism like the mushroom that has no sexual differentiation and no mechanism for signalling to a likely mate. Having several thousands of mating types, as some mushrooms do, is, however, remarkable - and even more remarkable is the fact that individuals only recognise that they have met a compatible mate after their cells have fused. How are such large numbers of mating types generated and what is the nature of the intracellular interaction that distinguishes self from non- self? Answers to these fascinating questions come from cloning some of the mating type genes of the ink cap mushroom Coprinus cinereus. A successful mating in Coprinus triggers a major switch in cell type, the conversion of a sterile mycelium with uninucleate cells (monokaryon) to a fertile mycelium with binucleate cells (dikaryon) which differentiates the characteristic fruit bodies. The mating type genes that regulate this developmental switch map to two multiallelic loci designated A and B and these must both carry different alleles for full mating compatibility. A and B independently regulate different steps in the developmental switch, making it possible to study just one component of the system and work in our laboratory has concentrated on understanding the structure and function of the A genes. It is estimated that some 160 different A mating types exist in nature, any two of which can together trigger the A-regulated part of sexual development. The first clue to how such large numbers are generated came from classical genetic analysis, which identified two functionally redundant A loci, (alpha) and beta. Functional redundancy is, indeed, the key to multiple A mating types and, as seen in Fig.1, molecular cloning has identified many more genes than was possible by recombination analysis.


2006 ◽  
Vol 274 (1607) ◽  
pp. 209-217 ◽  
Author(s):  
Leif Engqvist ◽  
Klaus Reinhold

Sperm competition theory predicts that when males are certain of sperm competition, they should decrease sperm investment in matings with an increasing number of competing ejaculates. How males should allocate sperm when competing with differently sized ejaculates, however, has not yet been examined. Here, we report the outcomes of two models assuming variation in males' sperm reserves and males being faced with different amounts of competing sperm. In the first ‘spawning model’, two males compete instantaneously and both are able to assess the sperm competitive ability of each other. In the second ‘sperm storage model’, males are sequentially confronted with situations involving different levels of sperm competition, for instance different amounts of sperm already stored by the female mating partner. In both of the models, we found that optimal sperm allocation will strongly depend on the size of the male's sperm reserve. Males should always invest maximally in competition with other males that are equally strong competitors. That is, for males with small sperm reserves, our model predicts a negative correlation between sperm allocation and sperm competition intensity, whereas for males with large sperm reserves, this correlation is predicted to be positive.


2020 ◽  
Author(s):  
Andrea Melissa Wilson ◽  
RV Lelwala ◽  
PWJ Taylor ◽  
MJ Wingfield ◽  
BD WINGFIELD

Abstract Background: Colletotrichum species are known to engage in unique sexual behaviours that differ significantly from the mating strategies of other filamentous ascomycete species. Most ascomycete fungi require the expression of both the MAT1-1-1 and MAT1-2-1 genes to regulate mating type and induce sexual reproduction. In contrast, all isolates of Colletotrichum are known to harbour only the MAT1-2-1 gene and yet, are capable of recognizing suitable mating partners and producing sexual progeny. The molecular mechanisms contributing to mating types and behaviours in Colletotrichum are thus unknown. Results: A comparative genomics approach analysing genomes from 47 Colletotrichum isolates was used to elucidate a putative molecular mechanism underlying the unique sexual behaviours observed in Colletotrichum species. The existence of only the MAT1-2 idiomorph was confirmed across all species included in this study. Comparisons at the loci harbouring the two mating pheromones and their cognate receptors revealed interesting patterns of gene presence and absence as well as gene loss. The results also showed that these genes have been lost multiple times over the evolutionary history of this genus. Conclusion: The multiple losses of the pheromone genes in these species suggest strong selection against the typical mating strategies seen in other species. This further suggests that these pheromones no longer play a role in mating type determination and that the species of this genus have undiscovered mechanisms by which to control mating type and mating partner recognition. This research thus provides a base from which further interrogation of this topic can take place.


2006 ◽  
Vol 3 (1) ◽  
pp. 36-39 ◽  
Author(s):  
Øystein Holand ◽  
Kjartan R Askim ◽  
Knut H Røed ◽  
Robert B Weladji ◽  
Hallvard Gjøstein ◽  
...  

In polygynous species, mate choice is an integrated part of sexual selection. However, whether mate choice occurs independently of the genetic relatedness among mating pairs has received little attention, although inbreeding may have fitness consequences. We studied whether genetic relatedness influenced females' choice of partner in a highly polygynous ungulate—the reindeer ( Rangifer tarandus )—in an experimental herd during two consecutive rutting seasons; the herd consisting of 75 females in 1999 and 74 females in 2000 was exposed to three 4.5-year-old adults and three 1.5-year-old young males, respectively. The females' distribution during peak rut was not influenced by their genetic relatedness with the dominant males of the mating groups. Further, genetic relatedness did not influence the actual choice of mating partner. We conclude that inbreeding avoidance through mating group choice as well as choice of mating partner, two interconnected processes of female mate choice operating at two different scales in space and time, in such a highly female-biased reindeer populations with low level of inbreeding may not occur.


2003 ◽  
Vol 1 (1) ◽  
pp. 147470490300100 ◽  
Author(s):  
Ronald S. Immerman ◽  
Wade C. Mackey

The mother-child bond is undoubtedly homologous with that of other primates (and mammals). However, the man-woman pair bond and man(to)child pair bond are not paralleled by any terrestrial primate nor many mammals. Hence, knowledge of primate behavior would not be predictive of the pan-human (i) social father and (ii) the extended pair bond between a man and woman (with the cultural overlay of marriage). It is suggested that female choice of mating partner shifted in the direction of a canid analogue in which men's motivations to share resources with the female and to exhibit paternalistic behaviors were positively selected. Accordingly, it would be predicted that, compared to other terrestrial primates, the neuro-hormonal bases for the mother-child affiliative bond would be similar, but the bases of man-woman affiliative bond and the man(to)child affiliative bond would be dissimilar.


Behaviour ◽  
1969 ◽  
Vol 34 (4) ◽  
pp. 267-285 ◽  
Author(s):  
Lynwood G. Clemens

AbstractEjaculation in the deermouse Peromyscus maniculatus gambeli was preceded by a sequence of brief penile penetrations (intromissions). In the sexually rested male the number of intromissions preceding the first ejaculation averaged 7 to 8. Each intromission was preceded by a short "bout" of running in which the male pursued the female. Following ejaculation the male failed to mount or investigate the female for the next 6 or 7 minutes. This "refractory period" was terminated when the male achieved another sequence of intromissions and ejaculated again. Males were considered sexually satiated after 30 minutes elapsed without any more ejaculations. Using this criterion it was found that from 3 to 6 ejaculations precede sexual satiation. The refractory periods became progressively longer following each successive ejaculation. If, following satiation, the female was removed and a different female was placed in the test area, all the males achieved additional intromissions and 8 out of 10 ejaculated. When the original mating partner was removed and then returned none of the males achieved ejaculation. This failure to achieve ejaculation with the original female was not due to changes in the condition of the female as a result of copulatory stimulation. Satiated males achieved additional ejaculations with females that had copulated with a different male just prior to the test just as frequently as they did with fresh females that had not copulated for 14 days. The condition of the female as affected by copulatory stimulation did influence other measures of the male's mating performance. These effects were seen most clearly in sexually rested males. The number of intromissions achieved prior to the first and the second ejaculation was greater with females that had received copulatory stimulation just prior to the test than it was with fresh females that had not copulated for 14 days. The time delay between intromissions was longer with fresh females. When males were allowed to achieve their first ejaculation with a fresh female and their second with the same female, there was no change in the number of intromissions from the first to the second ejaculation. This is in contrast to findings with the rat and hamster, in which species a decrease in intromission frequency occurs after the first ejaculation. The current study of the deermouse indicated that if the condition of the female was held constant by testing a male with a fresh female for the first ejaculation and another fresh female for the second ejaculation, a decrease in intromission frequency occurred. On the basis of these results it was concluded that: (i) sexual satiation in the male deermouse is, in part at least, specific to the particular female mating partner, and (2) changes in the condition of the female as a result of copulatory stimulation can have major effects on the "measure of male sexual performance".


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