scholarly journals Homology-Based Interactions between Small RNAs and Their Targets Control Dominance Hierarchy of Male Determinant Alleles of Self-Incompatibility in Arabidopsis lyrata

2021 ◽  
Vol 22 (13) ◽  
pp. 6990
Author(s):  
Shinsuke Yasuda ◽  
Risa Kobayashi ◽  
Toshiro Ito ◽  
Yuko Wada ◽  
Seiji Takayama

Self-incompatibility (SI) is conserved among members of the Brassicaceae plant family. This trait is controlled epigenetically by the dominance hierarchy of the male determinant alleles. We previously demonstrated that a single small RNA (sRNA) gene is sufficient to control the linear dominance hierarchy in Brassica rapa and proposed a model in which a homology-based interaction between sRNAs and target sites controls the complicated dominance hierarchy of male SI determinants. In Arabidopsis halleri, male dominance hierarchy is reported to have arisen from multiple networks of sRNA target gains and losses. Despite these findings, it remains unknown whether the molecular mechanism underlying the dominance hierarchy is conserved among Brassicaceae. Here, we identified sRNAs and their target sites that can explain the linear dominance hierarchy of Arabidopsis lyrata, a species closely related to A. halleri. We tested the model that we established in Brassica to explain the linear dominance hierarchy in A. lyrata. Our results suggest that the dominance hierarchy of A. lyrata is also controlled by a homology-based interaction between sRNAs and their targets.

Science ◽  
2014 ◽  
Vol 346 (6214) ◽  
pp. 1200-1205 ◽  
Author(s):  
Eléonore Durand ◽  
Raphaël Méheust ◽  
Marion Soucaze ◽  
Pauline M. Goubet ◽  
Sophie Gallina ◽  
...  

The prevention of fertilization through self-pollination (or pollination by a close relative) in the Brassicaceae plant family is determined by the genotype of the plant at the self-incompatibility locus (S locus). The many alleles at this locus exhibit a dominance hierarchy that determines which of the two allelic specificities of a heterozygous genotype is expressed at the phenotypic level. Here, we uncover the evolution of how at least 17 small RNA (sRNA)–producing loci and their multiple target sites collectively control the dominance hierarchy among alleles within the gene controlling the pollen S-locus phenotype in a self-incompatible Arabidopsis species. Selection has created a dynamic repertoire of sRNA-target interactions by jointly acting on sRNA genes and their target sites, which has resulted in a complex system of regulation among alleles.


Genetics ◽  
2020 ◽  
Vol 215 (3) ◽  
pp. 653-664
Author(s):  
Nicolas Burghgraeve ◽  
Samson Simon ◽  
Simon Barral ◽  
Isabelle Fobis-Loisy ◽  
Anne-Catherine Holl ◽  
...  

Small noncoding RNAs are central regulators of genome activity and stability. Their regulatory function typically involves sequence similarity with their target sites, but understanding the criteria by which they specifically recognize and regulate their targets across the genome remains a major challenge in the field, especially in the face of the diversity of silencing pathways involved. The dominance hierarchy among self-incompatibility alleles in Brassicaceae is controlled by interactions between a highly diversified set of small noncoding RNAs produced by dominant S-alleles and their corresponding target sites on recessive S-alleles. By controlled crosses, we created numerous heterozygous combinations of S-alleles in Arabidopsis halleri and developed an real-time quantitative PCR assay to compare allele-specific transcript levels for the pollen determinant of self-incompatibility (SCR). This provides the unique opportunity to evaluate the precise base-pairing requirements for effective transcriptional regulation of this target gene. We found strong transcriptional silencing of recessive SCR alleles in all heterozygote combinations examined. A simple threshold model of base pairing for the small RNA–target interaction captures most of the variation in SCR transcript levels. For a subset of S-alleles, we also measured allele-specific transcript levels of the determinant of pistil specificity (SRK), and found sharply distinct expression dynamics throughout flower development between SCR and SRK. In contrast to SCR, both SRK alleles were expressed at similar levels in the heterozygote genotypes examined, suggesting no transcriptional control of dominance for this gene. We discuss the implications for the evolutionary processes associated with the origin and maintenance of the dominance hierarchy among self-incompatibility alleles.


2018 ◽  
Author(s):  
N. Burghgraeve ◽  
S. Simon ◽  
S. Barral ◽  
I. Fobis-Loisy ◽  
A-C Holl ◽  
...  

AbstractSmall non-coding RNAs are central regulators of genome activity and stability. Their regulatory function typically involves sequence similarity with their target sites, but understanding the criteria by which they specifically recognize and regulate their targets across the genome remains a major challenge in the field, especially in the face of the diversity of silencing pathways involved. The dominance hierarchy among self-incompatibility alleles in Brassicaceae is controlled by interactions between a highly diversified set of small non-coding RNAs produced by dominant S-alleles and their corresponding target sites on recessive S-alleles. By controlled crosses, we created numerous heterozygous combinations of S-alleles in Arabidopsis halleri and developed an RT-qPCR assay to compare allele-specific transcript levels for the pollen determinant of self-incompatibility (SCR). This provides the unique opportunity to evaluate the precise base-pairing requirements for effective transcriptional regulation of this target gene. We found strong transcriptional silencing of recessive SCR alleles in all heterozygote combinations examined. A simple threshold model of base-pairing for the sRNA-target interaction captures most of the variation in SCR transcript levels. For a subset of S-alleles, we also measured allele-specific transcript levels of the determinant of pistil specificity (SRK) and found sharply distinct expression dynamics throughout flower development between SCR and SRK. In contrast to SCR, both SRK alleles were expressed at similar levels in the heterozygote genotypes examined, suggesting no transcriptional control of dominance for this gene. We discuss the implications for the evolutionary processes associated with the origin and maintenance of the dominance hierarchy among self-incompatibility alleles.


Genetics ◽  
1998 ◽  
Vol 150 (3) ◽  
pp. 1187-1198 ◽  
Author(s):  
Mikkel H Schierup ◽  
Xavier Vekemans ◽  
Freddy B Christiansen

Abstract Expectations for the time scale and structure of allelic genealogies in finite populations are formed under three models of sporophytic self-incompatibility. The models differ in the dominance interactions among the alleles that determine the self-incompatibility phenotype: In the SSIcod model, alleles act codominantly in both pollen and style, in the SSIdom model, alleles form a dominance hierarchy, and in SSIdomcod, alleles are codominant in the style and show a dominance hierarchy in the pollen. Coalescence times of alleles rarely differ more than threefold from those under gametophytic self-incompatibility, and transspecific polymorphism is therefore expected to be equally common. The previously reported directional turnover process of alleles in the SSIdomcod model results in coalescence times lower and substitution rates higher than those in the other models. The SSIdom model assumes strong asymmetries in allelic action, and the most recessive extant allele is likely to be the most recent common ancestor. Despite these asymmetries, the expected shape of the allele genealogies does not deviate markedly from the shape of a neutral gene genealogy. The application of the results to sequence surveys of alleles, including interspecific comparisons, is discussed.


2020 ◽  
Vol 16 (8) ◽  
pp. 20200468
Author(s):  
Steven J. Portugal ◽  
James R. Usherwood ◽  
Craig R. White ◽  
Daniel W. E. Sankey ◽  
Alan M. Wilson

Dominance hierarchies confer benefits to group members by decreasing the incidences of physical conflict, but may result in certain lower ranked individuals consistently missing out on access to resources. Here, we report a linear dominance hierarchy remaining stable over time in a closed population of birds. We show that this stability can be disrupted, however, by the artificial mass loading of birds that typically comprise the bottom 50% of the hierarchy. Mass loading causes these low-ranked birds to immediately become more aggressive and rise-up the dominance hierarchy; however, this effect was only evident in males and was absent in females. Removal of the artificial mass causes the hierarchy to return to its previous structure. This interruption of a stable hierarchy implies a strong direct link between body mass and social behaviour and suggests that an individual's personality can be altered by the artificial manipulation of body mass.


Evolution ◽  
2005 ◽  
Vol 59 (7) ◽  
pp. 1437 ◽  
Author(s):  
Barbara K. Mable ◽  
Alexander V. Robertson ◽  
Sara Dart ◽  
Christina Di Berardo ◽  
Laura Witham

Behaviour ◽  
1994 ◽  
Vol 129 (3-4) ◽  
pp. 225-242 ◽  
Author(s):  
David Glenn Smith

AbstractPaternity exclusion analysis was employed to estimate the reproductive success (RS) of 32 males who experienced at least one breeding season over the age of four years between 1977 and 1991 in a captive group of rhesus macaques (Macaca mulatta). Although three different males held alpha rank during the period, the male dominance hierarchy remained relatively stable even when the number of males was high. Average dominance rank and overall RS of males while in the group were strongly correlated. However, during most years the correlation between male dominance rank and RS was not statistically significant because males who achieved high rank 1)were those who experienced relatively high RS as lower ranking subadults and 2) maintained high dominance rank after experiencing a sustained decline in RS. Correlations between male dominance rank and RS were highest when the number of subadult males entering the dominance hierarchy was increasing and one or a very few males were least effective in monopolizing females. These results are not consistent with expectations based solely on the priority of access model of intrasexual selection. Female choice, as exemplified by the preference of females for mating with young males that are rising in rank, might also influence the evolution of social dominance in rhesus macaques.


Evolution ◽  
2005 ◽  
Vol 59 (7) ◽  
pp. 1437-1448 ◽  
Author(s):  
Barbara K. Mable ◽  
Alexander V. RobertsonSara Dart ◽  
Christina Di Berardo ◽  
Laura Witham

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