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GENE NETWORKS BEAT CANDIDATE GENES. "Studies in both model systems and in diverse plant lineages have demonstrated that floral morphology is not controlled by a single candidate symmetry gene or even a single set of genes, but rather by a complex network of genes that regulate symmetry patterns and lead to the diversity in shape within lineages." https://lnkd.in/dD4GcAS View in LinkedIn

DOWNSTREAM OF THE CANDIDATE GENES. "While the expression of TCP genes is spatially restricted in similar ways in groups in which bilateral symmetry has evolved independently, the expression patterns are not identical for each evolutionary event. Additionally, TCP gene expression is acting to regulate a cascade of genes that vary in their copy number and expression patterns." https://lnkd.in/dD4GcAS View in LinkedIn

CANDIDATE GENE QUESTIONS. "What is not clear from these studies, however, is the diversity of mechanisms by which the TCP genes may underlie changes in floral symmetry across these diverse lineages, or the selection process by which the genetic modifications underlying shifts in patterns of symmetry occurred." https://lnkd.in/dD4GcAS View in LinkedIn

WIDESPREAD CANDIDATE GENE. "A relationship was drawn between the differential expression of the TCP developmental gene(s) and phenotypic variation associated with fixed morphological diversification across angiosperm flowers. This fixed diversity is demonstrated across large evolutionary distances and across floral organ types, demonstrating the conserved nature of the TCP gene lineage and its role in floral symmetry patterns." https://lnkd.in/dD4GcAS View in LinkedIn

FLOWER SYMMETRY. "Subsequent studies demonstrated that this same class of genes was responsible for the evolution of symmetry across many lineages of flowering plants, with similar yet independently evolved genetic mechanisms underlying differential gene expression patterns." https://lnkd.in/dD4GcAS View in LinkedIn

SNAPDRAGON CANDIDATE GENE EXAMPLE. "For example, changes in the expression of the TCP gene lineage during floral development of Antirrhinum were shown to cause alterations in petal morphology in this model species, resulting in a shift from bilaterally symmetrical to radially symmetrical flowers." https://lnkd.in/dD4GcAS View in LinkedIn

TCP GENES. These are developmental transcription factor genes found only in vascular plants, involved in the evolution of key morphological features. https://en.m.wikipedia.org/wiki/TCP_protein_domain View in LinkedIn

ANCIENT PLAYERS. "These speculations on the origin of DNA fit well with hypotheses on viral origin that consider no longer viruses as fragments of genetic materials recently escaped from their hosts, but as ancient players in life evolution, possibly predating the divergence between the three domains of life." https://lnkd.in/dNTbYMw View in LinkedIn

ASSUMPTIONS WITH CANDIDATE GENES. "This approach requires two assumptions: one is that genes and gene regulatory networks (GRNs) responsible for developmental processes are conserved over large evolutionary distances. The second is that changes in the regulation of these genes, resulting in altered temporal and spatial expression patterns, affect the phenotype and thus are responsible for fixed differences in organismal morphology. For many studied developmental processes, these two assumptions appear to hold true." https://lnkd.in/dD4GcAS View in LinkedIn

CRITICAL ROLE. "The idea that viruses have played a critical role in the origin of DNA is in line with previous conception that retroviruses were relics of the RNA/DNA world transition." https://lnkd.in/dNTbYMw View in LinkedIn