Dataset Information

Partitioned expression of duplicated genes during development and evolution of a single cell in a polyploid plant.

ABSTRACT: Polyploidy is an important driver of eukaryotic evolution, evident in many animals, fungi, and plants. One consequence of polyploidy is subfunctionalization, in which the ancestral expression profile becomes partitioned among duplicated genes (termed homoeologs). Subfunctionalization appears to be a common phenomenon insofar as it has been studied, at the scale of organs. Here, we use a high-resolution methodology to investigate the expression of thousands of pairs of homoeologs during the development of a single plant cell, using as a model the seed trichomes ("cotton fiber") of allopolyploid (containing "A" and "D" genomes) cotton (Gossypium). We demonstrate that approximately 30% of the homoeologs are significantly A- or D-biased at each of three time points studied during fiber development. Genes differentially biased toward the A or D genome belong to different biological processes, illustrating the functional partitioning of genomic contributions during cellular development. Interestingly, expression of the biased genes was shifted strongly toward the agronomically inferior D genome. Analyses of homoeologous gene expression during development of this cell showed that one-fifth of the genes exhibit changes in A/D ratios, indicating that significant alteration in duplicated gene expression is fairly frequent even at the level of development and maturation of a single cell. Comparing changes in homoeolog expression in cultivated versus wild cotton showed that most homoeolog expression bias reflects polyploidy rather than domestication. Evidence suggests, however, that domestication may increase expression bias in fibers toward the D genome, potentially implicating D-genome recruitment under human selection during domestication.

SUBMITTER: Hovav R

PROVIDER: S-EPMC2329682 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Partitioned expression of duplicated genes during development and evolution of a single cell in a polyploid plant.

Hovav Ran R Udall Joshua A JA Chaudhary Bhupendra B Rapp Ryan R Flagel Lex L Wendel Jonathan F JF

Proceedings of the National Academy of Sciences of the United States of America 20080417 16

Polyploidy is an important driver of eukaryotic evolution, evident in many animals, fungi, and plants. One consequence of polyploidy is subfunctionalization, in which the ancestral expression profile becomes partitioned among duplicated genes (termed homoeologs). Subfunctionalization appears to be a common phenomenon insofar as it has been studied, at the scale of organs. Here, we use a high-resolution methodology to investigate the expression of thousands of pairs of homoeologs during the devel ...[more]

PMID: 18420816

Similar Datasets

Project description:BackgroundGene duplication provides resources for developing novel genes and new functions while retaining the original functions. In addition, alternative splicing could increase the complexity of expression at the transcriptome and proteome level without increasing the number of gene copy in the genome. Duplication and alternative splicing are thought to work together to provide the diverse functions or expression patterns for eukaryotes. Previously, it was believed that duplication and alternative splicing were negatively correlated and probably interchangeable.ResultsWe look into the relationship between occurrence of alternative splicing and duplication at different time after duplication events. We found duplication and alternative splicing were indeed inversely correlated if only recently duplicated genes were considered, but they became positively correlated when we took those ancient duplications into account. Specifically, for slightly or moderately duplicated genes with gene families containing 2 - 7 paralogs, genes were more likely to evolve alternative splicing and had on average a greater number of alternative splicing isoforms after long-term evolution compared to singleton genes. On the other hand, those large gene families (contain at least 8 paralogs) had a lower proportion of alternative splicing, and fewer alternative splicing isoforms on average even when ancient duplicated genes were taken into consideration. We also found these duplicated genes having alternative splicing were under tighter evolutionary constraints compared to those having no alternative splicing, and had an enrichment of genes that participate in molecular transducer activities.ConclusionsWe studied the association between occurrences of alternative splicing and gene duplication. Our results implicate that there are key differences in functions and evolutionary constraints among singleton genes or duplicated genes with or without alternative splicing incidences. It implies that the gene duplication and alternative splicing may have different functional significance in the evolution of speciation diversity.

Project description:BACKGROUND: Starch is the main source of carbon storage in the Archaeplastida. The starch biosynthesis pathway (sbp) emerged from cytosolic glycogen metabolism shortly after plastid endosymbiosis and was redirected to the plastid stroma during the green lineage divergence. The SBP is a complex network of genes, most of which are members of large multigene families. While some gene duplications occurred in the Archaeplastida ancestor, most were generated during the sbp redirection process, and the remaining few paralogs were generated through compartmentalization or tissue specialization during the evolution of the land plants. In the present study, we tested models of duplicated gene evolution in order to understand the evolutionary forces that have led to the development of SBP in angiosperms. We combined phylogenetic analyses and tests on the rates of evolution along branches emerging from major duplication events in six gene families encoding sbp enzymes. RESULTS: We found evidence of positive selection along branches following cytosolic or plastidial specialization in two starch phosphorylases and identified numerous residues that exhibited changes in volume, polarity or charge. Starch synthases, branching and debranching enzymes functional specializations were also accompanied by accelerated evolution. However, none of the sites targeted by selection corresponded to known functional domains, catalytic or regulatory. Interestingly, among the 13 duplications tested, 7 exhibited evidence of positive selection in both branches emerging from the duplication, 2 in only one branch, and 4 in none of the branches. CONCLUSIONS: The majority of duplications were followed by accelerated evolution targeting specific residues along both branches. This pattern was consistent with the optimization of the two sub-functions originally fulfilled by the ancestral gene before duplication. Our results thereby provide strong support to the so-called "Escape from Adaptive Conflict" (EAC) model. Because none of the residues targeted by selection occurred in characterized functional domains, we propose that enzyme specialization has occurred through subtle changes in affinity, activity or interaction with other enzymes in complex formation, while the basic function defined by the catalytic domain has been maintained.

Dataset Information

Partitioned expression of duplicated genes during development and evolution of a single cell in a polyploid plant.

Publications

Partitioned expression of duplicated genes during development and evolution of a single cell in a polyploid plant.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets