Where whole‐genome duplication is most beneficial – Adaptation of mangroves to a wide salinity range between land and sea

Abstract The duplication of preexisting genes has played a major role in evolution. To understand the evolution of genetic complexity it is important to reconstruct the phylogenetic history of the genome. A widely held view suggests that the vertebrate genome evolved via two successive rounds of whole-genome duplication. To test this model we have isolated seven new T-box genes from the primitive chordate amphioxus. We find that each amphioxus gene generally corresponds to two or three vertebrate counterparts. A phylogenetic analysis of these genes supports the idea that a single whole-genome duplication took place early in vertebrate evolution, but cannot exclude the possibility that a second duplication later took place. The origin of additional paralogs evident in this and other gene families could be the result of subsequent, smaller-scale chromosomal duplications. Our findings highlight the importance of amphioxus as a key organism for understanding evolution of the vertebrate genome.

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Comparative Mapping Between Coho Salmon (Oncorhynchus kisutch) and Three Other Salmonids Suggests a Role for Chromosomal Rearrangements in the Retention of Duplicated Regions Following a Whole Genome Duplication Event

G3 Genes|Genome|Genetics ◽

10.1534/g3.114.012294 ◽

2014 ◽

Vol 4 (9) ◽

pp. 1717-1730 ◽

Cited By ~ 37

Author(s):

M. Kodama ◽

M. S. O. Brieuc ◽

R. H. Devlin ◽

J. J. Hard ◽

K. A. Naish

Keyword(s):

Comparative Mapping ◽

Whole Genome Duplication ◽

Genome Duplication ◽

Coho Salmon ◽

Chromosomal Rearrangements ◽

Oncorhynchus Kisutch ◽

Duplication Event ◽

Whole Genome ◽

Genome Duplication Event ◽

Whole Genome Duplication Event

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Comparative regulomics supports pervasive selection on gene dosage following whole genome duplication

Genome Biology ◽

10.1186/s13059-021-02323-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Gareth B. Gillard ◽

Lars Grønvold ◽

Line L. Røsæg ◽

Matilde Mengkrog Holen ◽

Øystein Monsen ◽

...

Keyword(s):

Genome Evolution ◽

Whole Genome Duplication ◽

Genome Stability ◽

Genome Duplication ◽

Gene Dosage ◽

Whole Genome ◽

Specific Expression ◽

Tissue Specific ◽

Genome Doubling ◽

Expression Evolution

Abstract Background Whole genome duplication (WGD) events have played a major role in eukaryotic genome evolution, but the consequence of these extreme events in adaptive genome evolution is still not well understood. To address this knowledge gap, we used a comparative phylogenetic model and transcriptomic data from seven species to infer selection on gene expression in duplicated genes (ohnologs) following the salmonid WGD 80–100 million years ago. Results We find rare cases of tissue-specific expression evolution but pervasive expression evolution affecting many tissues, reflecting strong selection on maintenance of genome stability following genome doubling. Ohnolog expression levels have evolved mostly asymmetrically, by diverting one ohnolog copy down a path towards lower expression and possible pseudogenization. Loss of expression in one ohnolog is significantly associated with transposable element insertions in promoters and likely driven by selection on gene dosage including selection on stoichiometric balance. We also find symmetric expression shifts, and these are associated with genes under strong evolutionary constraints such as ribosome subunit genes. This possibly reflects selection operating to achieve a gene dose reduction while avoiding accumulation of “toxic mutations”. Mechanistically, ohnolog regulatory divergence is dictated by the number of bound transcription factors in promoters, with transposable elements being one likely source of novel binding sites driving tissue-specific gains in expression. Conclusions Our results imply pervasive adaptive expression evolution following WGD to overcome the immediate challenges posed by genome doubling and to exploit the long-term genetic opportunities for novel phenotype evolution.

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Chromosome-level genome assembly of Ophiorrhiza pumila reveals the evolution of camptothecin biosynthesis

Nature Communications ◽

10.1038/s41467-020-20508-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Amit Rai ◽

Hideki Hirakawa ◽

Ryo Nakabayashi ◽

Shinji Kikuchi ◽

Koki Hayashi ◽

...

Keyword(s):

Genome Assembly ◽

Whole Genome Duplication ◽

Experimental Validation ◽

Genome Duplication ◽

Indole Alkaloids ◽

Whole Genome ◽

Comparative Genome Analysis ◽

Plant Genomes ◽

Genome Triplication ◽

Chromosome Level

AbstractPlant genomes remain highly fragmented and are often characterized by hundreds to thousands of assembly gaps. Here, we report chromosome-level reference and phased genome assembly of Ophiorrhiza pumila, a camptothecin-producing medicinal plant, through an ordered multi-scaffolding and experimental validation approach. With 21 assembly gaps and a contig N50 of 18.49 Mb, Ophiorrhiza genome is one of the most complete plant genomes assembled to date. We also report 273 nitrogen-containing metabolites, including diverse monoterpene indole alkaloids (MIAs). A comparative genomics approach identifies strictosidine biogenesis as the origin of MIA evolution. The emergence of strictosidine biosynthesis-catalyzing enzymes precede downstream enzymes’ evolution post γ whole-genome triplication, which occurred approximately 110 Mya in O. pumila, and before the whole-genome duplication in Camptotheca acuminata identified here. Combining comparative genome analysis, multi-omics analysis, and metabolic gene-cluster analysis, we propose a working model for MIA evolution, and a pangenome for MIA biosynthesis, which will help in establishing a sustainable supply of camptothecin.

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