Major plant science break-through at the UEA - with seeds from Ipswich

Thompson & Morgan seed catalogue 1995

Thompson & Morgan seed catalogue 1995 - Credit: Archant

Scientists have identified the cluster of genes responsible for reproductive traits in the Primula flower, first noted as important by Charles Darwin more than 150 years ago.

And they have done it using Primrose seeds purchased from Ipswich seed and plant merchant Thompson & Morgan

Darwin hypothesised that some plant species with two distinct forms of flower, where male and female reproductive organs were of differing lengths, had evolved that way to promote out-crossing by insect pollinators.

His ground-breaking insight into the significance of the two forms of flower known as ‘pins’ and ‘thrums’ coined the term ‘heterostyly’, and subsequent studies contributed to the foundation of modern genetic theory.

And now scientists at the University of East Anglia, working at the John Innes Centre, have identified exactly which part of these species’ genetic code made them that way, through an event that occurred more than 51 million years ago.

Prof Philip Gilmartin from UEA’s School of Biological Sciences said: “To identify the genes which control the biology noted by Darwin is an exciting moment. Many studies have been done over the past decades to explore the genetic basis of this phenomenon but now we have pinpointed the supergene directly responsible, the S locus.”

Supergenes are clusters of closely-associated genes which are always inherited together as a unit and allow complex biology to be controlled. Researchers worked with the Earlham Institute to map the plant’s genes and sequence the Primula genome to find the specific gene cluster responsible for creating the differing flower morphs.

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Prof Gilmartin said: “Not only did we identify the supergene but we found it is specific to just one of the flower forms, the thrum. This insight has profound implications for our understanding of a key evolutionary innovation of flowering plants.

“Understanding of the genetics which underpin flower development and reproduction of a species broadens our knowledge about the entire system of pollination, which underpins biodiversity and food security.”

Prof Gilmartin has been researching the origins of heterostyly for a large part of his career.

He said: “This study answers some of the crucial questions that have been asked since Darwin’s time, and for me since I bought my first packet of Primula seeds twenty years ago.”

The study ‘Genetic architecture and evolution of the S locus supergene in Primula vulgaris’ was published in the journal Nature Plants, in December 2016.

Professor Gilmartin revealed the seeds came from the Ipswich firm.

Prof. Gilmartin tweeted Thompson and Morgan to say that his discovery had all started with a packet of Primula seeds that he had bought from the seed merchants’ 1995 catalogue – and he added a photo of the catalogue’s now worn front cover. In a conversation with Prof. Gilmartin, it was established that the variety in question was Primula ‘Blue Jeans’.

He said that the choice of this particular F1 Hybrid Primula variety was pivotal as it gave a very homogenous parent line on which to base his research on.