Scientists set out to capture a detailed family tree of the sunflower family, a family with over 28,000 species, based on DNA sequences. The sunflower head, which is radially symmetric (can be divided into equal halves in any direction), is made of multiple smaller flowers, which are bilaterally symmetric (has one line that divides the flower into equal halves). Hong Ma, the lead, and his team used low-coverage genome sequences through genome skimming to "increase the number of species available for comparison" (Science Daily). Along with the samples the team provided, they also used publicly available and newly generated data to collect a total of 706 different species which form 16 subfamilies, 41 tribes, and 144 subtribe level groups for the sunflower family. The study found that bilateral symmetry has independently evolved and been lost multiple times, which means the sunflower family shows signs of convergent evolution. They also found a gene, CYC2, that was activated in species which bilaterally symmetric flowers, which also added substance to the convergent theory hypothesis. Ultimately, the scientists found that the convergent evolution is likely due to changes throughout time in expression patterns of the CYC2 gene.
The sunflower family is one of the two largest plant families with various agricultural and horticultural value. The family holds over 28,000 species and has evolved over thousands of years. Due to their huge role in both the agricultural and horticultural worlds, I feel that their detailed family tree was very interesting to see but also to understand trends seen in the tree, like the CYC2 expression patterns. It's interesting to see how much biodiversity there is within one species or family, and how it evolves and repeats over time. Gaining a more detailed family tree of such a dominant plant family could answer many questions about plant and genetic evolution, as well as questions about other plants with similar traits.
Hi Jacqueline,
ReplyDeleteThe thorough family tree research of the sunflower family shows the complex steps of convergent evolution in plants by showing the development of bilateral symmetry and the function of the CYC2 gene. This family's rich biodiversity highlights its importance for horticulture and agriculture, providing important insights into genetic and evolutionary processes that might guide study on related features in other plant species. Great post!