Deoxyribonucleic acid (DNA) is the foundation of all evolutionary processes. Researchers knew the complex evolutionary history of how most organism evolve on opposite sides of the world. But until now, the knew little about the evolutionary origins of one peculiar fruit. Most species are diploids — having two genome from two origins; but this fruit is an octoploid — having it’s genome from eight different origins. Dear friends, here is the evolutionary tale of the strawberry fruit — having it’s genome from eight different origins.
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Hey There, I Have Eight Parents
In a 2018 study published in Nature Genetics, researchers explain the evolutionary epic of how the strawberry became an octoploid, and the genetics that determine important fruit quality traits. The four diploid species are native to Europe, Asia, and North America, but the wild octoploids are found throughout the Americas.
Their new paper suggests a series of intermediate polyploids, tetraploid, and hexaploid that probably evolved in Asia, long before the octoploid made it’s debut the Americas, which were endemic to the continent. The strawberry is one of the only three high-value fruit crops relatively unique and native to the Americas. These octoploids (in our case strawberries) were being propagated roughly 300 years ago, and ever since, researchers have enhance their variety development all over the world.
For this reason, the researchers hypothesized that, an unbalanced expression of traits each diploid parental species contributes, called sub-genome dominance, would likely also be present in the octoploid strawberry — and they were right.
Genetic Extended Family System
“For the first time, analysis of the genome enabled us to identify all four extant relatives of the diploid species that sequentially hybridized to create the octoploid strawberry,” says Patrick Edger, an assistant professor of horticulture at Michigan State University, and co-author of the new paper. “It’s a rich history that spans the globe, ultimately culminating in the fruit so many enjoy today.”
The genomic discoveries will advance the trait selection process, bringing about a more precise method of breeding for this important worldwide crop. The genome will also enable studies previously unthinkable in strawberries, and will help tackle difficult breeding and genetics questions, researchers say.
“Without the genome we were flying blind,” says co-author Steven Knapp, a plant scientist from the University of California, Davis. “I remember the first time I saw a visualization of the assembled genome, which went from a complex jumble of DNA molecules of 170 billion nucleotides to an organized and ordered string of 830 million base pairs. That was a special moment that changed everything for us in strawberry.”
Knapp says that, historically, scientists studying complex biological phenomena in strawberries have tended to focus on diploid relatives because of the complexity of the octoploid, even though genetic analyses in the octoploid are actually straightforward once one has a good road map.
The Breed Of Multi Parenthood
The cultivation of strawberries has seen a massive success in terms of yielding for most modern cultivars — that has been the main catalyst for global production. Although there are challenges in cultivating, most farmers continue to redesign cultivars and enhance it’s genetic varieties from both wild and exotic species. Genomes are vital in enhancing strawberry breeding and cultivar development.
The United States is the world’s highest producer of strawberries, yielding roughly a third of the world’s total; and in 2016, produced over 1.5 million tons. Genome improvement of the varieties could boost the already thriving business. Several research has contributed to the sequence and analysis of strawberry genome, and this has provided more information about it’s origin and traits.
Source: University of California, and Michigan State University.
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Written by: Nana Kwadwo, Wed, Aug 14, 2019.