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Beautiful dry stone wall. View in LinkedIn

SO ENDS this first of two weekends on the theme of floral symmetry. Symmetry is a pervasive theme in nature, from the quantum to the biological. It is still not clear why symmetry is such a powerful force, so seemingly keenly essential. In the case of flowers, the pollinators could as easily, it seems, have been conditioned on asymmetric flowers. But as we see, plants go to complicated generic solutions to maintain precise symmetric control. View in LinkedIn

SNAPDRAGON MORPHOLOGY. "In A. majus, both paralogues are expressed in the dorsal petals only; however, one copy is more restricted than the other. In other groups, however, the CYC2 expression pattern...has been found. CYC2 genes then activate RAD in the broadest zone of expression. This results in differential expression of DIV, with diffuse expression in dorsal regions and localized epidermal expression in ventral regions. This could result in trichomes developing only in the ventral region." http://onlinelibrary.wiley.com/doi/10.1111/nph.13198/full View in LinkedIn

GENE DUPLICATION EVENT. "A shift to a bilaterally symmetrical flower generally entails two correlated events: the duplication into two CYC2 paralogues and the dorsal restriction of both paralogues. Additionally, in many groups one paralogue is more dorsally restricted than the other paralogue." http://onlinelibrary.wiley.com/doi/10.1111/nph.13198/full View in LinkedIn

DOWNSTREAM CONTROL. "When CYC2 is ubiquitously expressed, then RAD is activated throughout the corolla, which inhibits DIV. DIV remains diffusely expressed throughout the corolla, perhaps not sufficiently to result in the up-regulation of AmMYBL1, leading to the loss of trichomes." http://onlinelibrary.wiley.com/doi/10.1111/nph.13198/full View in LinkedIn

GENE CASCADE. "In the absence of RAD, DIVARICATA (DIV) localizes to the surface epidermal cells where it may up-regulate AmMYBL1 (a MIXTA-like gene), resulting (at least in Antirrhinum majus) in trichome formation throughout the corolla tube." http://onlinelibrary.wiley.com/doi/10.1111/nph.13198/full View in LinkedIn

SYMMETRIC GENE EXPRESSION. "In radially symmetrical flowers, expression of CYCLOIDEA2 (CYC2) genes have been shown to be either not expressed or ubiquitously expressed. When CYC2 is not expressed, RADIALIS (RAD) is no longer activated." (See Figure 1). http://onlinelibrary.wiley.com/doi/10.1111/nph.13198/full View in LinkedIn

BILATERAL HYPOTHESIS. "This sets up the hypothesis that species with bilaterally symmetrical flowers are homologous in their capacity to undergo a shift to dorsal expression, even though the location of gene expression itself is independently derived across independently evolved bilaterally symmetrical groups." http://onlinelibrary.wiley.com/doi/10.1111/nph.13198/full View in LinkedIn

The action of transposons giving this variegated color, just jumping genes. View in LinkedIn

PLANT SOUNDS. "That plants produce sound waves has been known for some time. Specifically, plants emit sound waves at the lower end of the audio range within 10–240 Hz (audio acoustic emissions) as well as ultrasonic acoustic emissions (UAE) ranging from 20 to 300kHz. Over the last 45 years, these acoustic emissions (and particularly the UAE) have been measured and described several times." https://lnkd.in/dd33rp7 View in LinkedIn