Flowering Plants’ Tiny Genome Equals Evolutionary Success

Flowering Plants’ Tiny Genome Equals Evolutionary Success

It’s been so long since I’ve seen a flower out in the wild; I’m having a hard time believing they’ll ever return! But, of course, they will, fulfilling a genetic legacy that has made flowering plants (or angiosperms) the dominant plant type on Earth.
Flowering plants edged out former first-place gymnosperms (which include conifers and ferns) around 150 million years ago, but until a recent co-study from teams out of San Francisco State University and Yale, scientists were stumped (pun intended!) as to how the small, colourful plants did it. It turns out, it likely had to do with their very smallness — of their genome
The team analyzed data held by the Royal Botanic Gardens, Kew (in London, UK), and compared genome sizes to physical properties like the number of leaf pores, and rates of leaf water loss and photosynthesis. The researchers found that the rise and continued success of flowering plants on Earth is a result of what they termed “genome downsizing.” From the BBC:
“By shrinking the size of the genome, which is contained within the nucleus of the cell, plants can build smaller cells.

In turn, this allows greater carbon dioxide uptake and carbon gain from photosynthesis, the process by which plants use light energy to turn carbon dioxide and water into glucose and oxygen.

Angiosperms can pack more veins and pores into their leaves, maximizing their productivity.

The researchers say genome-downsizing happened only in the angiosperms, and this was ‘a necessary prerequisite for rapid growth rates among land plants.’”
Plants with smaller genomes were therefore far more efficient at, well, being plants, which has lead to their dominance. Their aesthetic appeal to humans is a lucky side effect!
This landmark discovery has resulted in further, refined questions that scientists should have fun answering: like, why have ferns, ginkgo, and conifers still survived, if, by the metric set by this research, they are no longer the “fittest” plants? While I’m sure the answer will be fascinating, I confess I’m happy with all plants… Though at this moment deep in February, I’m not going to blame myself for treasuring crocuses or daffodils just a tiny bit more!