Sequence analysis of two alleles reveals that intra-and intergenic recombination played a role in the evolution of the radish fertility restorer (Rfo)

Background \ud Land plant genomes contain multiple members of a eukaryote-specific gene family encoding proteins with pentatricopeptide repeat (PPR) motifs. Some PPR proteins were shown to participate in post-transcriptional events involved in organellar gene expression, and this type of function is now thought to be their main biological role. Among PPR genes, restorers of fertility (Rf) of cytoplasmic male sterility systems constitute a peculiar subgroup that is thought to evolve in response to the presence of mitochondrial sterility-inducing genes. Rf genes encoding PPR proteins are associated with very close relatives on complex loci. \ud Results \ud We sequenced a non-restoring allele (L7rfo) of the Rfo radish locus whose restoring allele (D81Rfo) was previously described, and compared the two alleles and their PPR genes. We identified a ca 13 kb long fragment, likely originating from another part of the radish genome, inserted into the L7rfo sequence. The L7rfo allele carries two genes (PPR-1 and PPR-2) closely related to the three previously described PPR genes of the restorer D81Rfo allele (PPR-A, PPR-B, and PPR-C). Our results indicate that alleles of the Rfo locus have experienced complex evolutionary events, including recombination and insertion of extra-locus sequences, since they diverged. Our \ud analyses strongly suggest that present coding sequences of Rfo PPR genes result from intragenic recombination. We found that the 10 C-terminal PPR repeats in Rfo PPR gene encoded proteins result from the tandem duplication of a 5 PPR repeat block. \ud Conclusions \ud The Rfo locus appears to experience more complex evolution than its flanking \ud sequences. The Rfo locus and PPR genes therein are likely to evolve as a result of \ud intergenic and intragenic recombination. It is therefore not possible to determine which genes on the two alleles are direct orthologs. Our observations recall some \ud previously reported data on pathogen resistance complex loci. \u

Implementation of a Practice Development Model to Reduce the Wait for Autism Spectrum Diagnosis in Adults

This study examined waiting times for diagnostic assessment of Autism Spectrum Disorder in 11 adult services, prior to and following the implementation of a 12 month change program. Methods to support change are reported and a multi-level modelling approach determined the effect of the change program on overall wait times. Results were statistically significant (b = − 0.25, t(136) = − 2.88, p = 0.005). The average time individuals waited for diagnosis across all services reduced from 149.4 days prior to the change program and 119.5 days after it, with an average reduction of 29.9 days overall. This innovative intervention provides a promising framework for service improvement to reduce the wait for diagnostic assessment of ASD in adults across the range of spectrum presentations

Evolutionary dynamics of a locus of fertility restoration in plants

Abstract: In higher plants, hermaphrodites may genetically loose their male fertility through the cytoplasmic male sterility (CMS) system. In radish, a nuclear locus, denoted Rfo, has evolved that is able to counteract the effect of CMS and restore the fertility. This locus encodes three similar genes in tandem that belong to the pentatricopeptide repeat (PPR) family and each gene encloses a tandem repeat of PPR motif. Among the hundreds of members of this family, some play a role in the post-transcriptional gene regulation in organelles (mitochondria and chloroplasts). In this study, we recently sequenced a European non-restorer allelic locus and compare it to the original Rfo restorer allele to investigate its evolutionary dynamics. We conducted bioinformatic analysis to determine the putative border of tandem duplications both at protein motif level and at gene level. Our results present the picture of complex evolution with multiple gene duplications at a fast evolving locus

Evolutionary Dynamics of the Restorer and a non-restorer Allelic Rfo Locus.

National audienceThe Rfo locus, first described in Asian radish cultivars and later introduced into Brassica, is involved in the restoration of fertility in the Ogura cytoplasmic male sterility system (CMS). CMS systems are constituted of two actors: a mitochondrial protein that causes male sterility and a nuclear gene that encodes a mitochondria-targeted protein able to impair the expression of the sterility gene. The nuclear restorer gene in the Rfo-Ogura system, as all identified restorer genes (with the only exception of the Rf2 Texas maize restorer), encodes a protein belonging to the pentatricopeptide repeat (PPR) family. The PPR gene family is a very large family in plants, with about 450 members in A. thaliana, and their function is largely unknown, although some members have proven to play roles in posttranscriptional organelle gene regulation. Recent studies analyzing chromosomes regions with duplicated PPR genes (allelic variants of a restorer locus in rice and two chromosome regions in A. thaliana) suggest revealed high levels of recombination in these regions. In addition, restorer genes (because of their ability to adapt to specificity changing/fast evolving targets) are evolved in a similar way as “resistant genes”. Anyway, evolutionary dynamics of these loci is largely unknown so far. In the Rfo region, the restorer gene seems to be duplicated too: three genes encoding highly related PPR proteins are present in the Rfo locus (even if just one of the proteins is able to restorer fertility). We recently sequenced a European non-restorer allelic locus. Analysis of this sequence shows the presence of only two PPR genes in an apparently very dynamic region. In this study, we analyzed the European allelic variant sequence of the Rfo locus and the possible evolutionary events that occurred in both loci, in order to give insight into the dynamics and evolution of the Rfo locus