A team of researchers from the University of East Anglia, Earlham Institute and the UK’s National Institute for Agricultural Botany has successfully sequenced the genome of the common primrose (Primula vulgaris), a species of flowering plant native to western and southern Europe, northwest Africa, and parts of southwest Asia.
The common primrose (Primula vulgaris). Image credit: GT 1976 / CC BY-SA 4.0.
Primrose plants flower in one of two ways: they either have a long style and low anthers, or a short style and elevated anthers — known as pins or thrums.
Victorian naturalist Charles Darwin was intrigued as to why some species, such as the primrose, develop two different forms of flowers, and devoted a whole book to the subject. He concluded from his studies that they provided a mechanism to promote outcrossing between individuals.
More recently, a cluster of genes known as the S (Style length) locus has been shown to be the control center for the development of the flowers.
This S locus is absent from half the individuals of the primrose, this cluster switches some genes on and others off, giving different patterns of gene expression in pin and thrum flowers.
In an earlier study, University of East Anglia’s Dr. Philip Gilmartin and co-authors sequenced the S-locus and described aspects of its evolution.
In the new study, they sequenced and assembled 87% of the predicted 474-million-base-pair primrose genome.
The researchers found that the S locus controls hundreds of genes across the genome.
They also identified genes that are activated in its absence, in the pin form of the flower.
“We started many years ago with a packet of seeds and a vision to understand the molecular genetics and developmental biology of the reproductive system Darwin described in 1862,” Dr. Gilmartin said.
“Completion of the genome sequence paves the way to identify the genes that are regulated by the S locus, and adds more pieces to the puzzle.”
The results were published in the journal Scientific Reports.
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Jonathan M. Cocker et al. 2018. Primula vulgaris (primrose) genome assembly, annotation and gene expression, with comparative genomics on the heterostyly supergene. Scientific Reports 8, article number: 17942; doi: 10.1038/s41598-018-36304-4
