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BILATERAL COLLABORATION. "New data reveal a two-way relationship between early reproductive cells and their helpers involving complex epigenetic and signaling networks determining cell number and fate. Later, the egg cell plays a central role in specifying accessory cells, whereas in both gametophytes, companion cells contribute non-cell-autonomously to the epigenetic landscape of the gamete genomes." http://www.sciencedirect.com/science/article/pii/S1534580713000427 View in LinkedIn

LAND PLANT CHARACTERISTICS. #3. "Third, they retain the fertilized egg (i.e. the zygote) within the archegonium, wherein the sporophyte embryo is nurtured and protected. The retention of the diploid embryo within the archegonium is the reason why the land plants are called ‘embryophytes’ and why the older literature referred to them as the Archegoniatae." http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2009.03054.x/full View in LinkedIn

SOMA AND GERM COLLABORATION. "Importantly, development of male and female gametes does not occur in isolation. The formation of meiocytes, gametophytes, and gametes requires the active presence of neighboring helper cells. Recent data on the interaction between reproductive cell lines and these largely somatic helper populations highlight not only the complexity of this relationship and the significance of the events it regulates but also its two-way nature." http://www.sciencedirect.com/science/article/pii/S1534580713000427 View in LinkedIn

LAND PLANT CHARACTERISTICS. #2. "Second, they develop multicellular, parenchymatous structures that produce eggs and sperm (called archegonia and antheridia, respectively)." http://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2009.03054.x/full View in LinkedIn

"THE CUES that mediate the transition of the different stages of the life cycle are likely to involve epigenetic mechanisms." http://rstb.royalsocietypublishing.org/content/367/1588/508.short View in LinkedIn

LAND PLANT CHARACTERISTICS. #1. "The embryophytes are unique among all extant lineages in possessing three important and interrelated reproductive attributes. First, they possess a sexual life cycle that requires an alternation between a multicellular haploid generation, which produces sperm and egg cells (the gametophyte), and a multicellular diploid generation, which produces meiospores with sporopollenin-rich walls (the sporophyte)." https://lnkd.in/dcZcdNY View in LinkedIn

CONTROL SYSTEMS. "Evidence is accumulating that major gene-switching events in plants, such as flowering, are regulated by complex control systems which ensures that development occurs only in the correct groups of cells at the appropriate time. A similar, or more sophisticated system might thus be expected to regulate alternation of generation." http://onlinelibrary.wiley.com/doi/10.1111/j.1469-185X.1994.tb01277.x/abstract View in LinkedIn

DIFFERENT EVOLUTIONARY PATHS. "The developmental changes involved in the alternation of generation represent the major gene-switching events in the life history of plants. While a large number of genes are common to both sporophyte and gametophyte, many thousand sequences are specifically expressed in each generation; indeed, certain key constituents (e.g. tubulin) are encoded by different genes in each generation, indicating that sporophyte and gametophyte are responding to different evolutionary pressures." https://lnkd.in/d7TmtBz View in LinkedIn

GENERATION-SPECIFIC GENES. "Some genes also have ancient functions that are restricted to the diploid phase of the life cycle (zygote and/or sporophyte). Some genes have ancient functions that are exclusive to either the sporophyte or the gametophyte generation." http://rstb.royalsocietypublishing.org/content/367/1588/508.short View in LinkedIn

RADIATION BY EXAPTATION. "The elaboration of the sporophyte generation, and particularly the large radiation of morphological forms during the Devonian period, was partially achieved through the recruitment of genes and genetic mechanisms that had previously evolved and functioned in the gametophyte generation of charophytes and early land plants." http://rstb.royalsocietypublishing.org/content/367/1588/508.short View in LinkedIn