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ACROSS KINGDOMS. “In normal mammalian somatic tissues, the stem or progenitor cells with high proliferation capacity have telomerase competence or the ability to express telomerase. In addition, increasing evidence has linked telomerase expression to cell proliferation rates. This model was extended by findings in the plant kingdom. Cells with high proliferation capacity and high mitotic activity reside in meristematic tissue. Telomerase activities were detected in these tissues as well as in cultured cells, whereas non-dividing cells from leaves and axillary buds were telomerase negative.” http://onlinelibrary.wiley.com/doi/10.1016/S0014-5793(98)01020-5/full View in LinkedIn

TELOMERASE LEVELS. “While normal human cells have little or no telomerase, stem cells were found to have high levels. Cancer cells, which have very high telomerase activity, are thought to achieve immortality in this way. It has since been established that telomerase defects are behind some inherited diseases, such as congenital aplastic anaemia, where stem cells in the bone marrow do not replicate sufficiently." http://www.bionews.org.uk/page_367898.asp View in LinkedIn

TETRAHYMENA THERMOPHILA “contains telomerase, that could replenish telomeres. Dr Blackburn established this unequivocally by mutating the telomerase gene in the tetrahymena and showing that this caused cell malfunction.” https://lnkd.in/d-EtCGX View in LinkedIn

VERY VARIED SYSTEM. "Some plants have only one type of sporophyte, but two types of gametophytes (essentially male and female gametophytes; the male only produces sperm, the female only produces eggs). Other plants have male and female sporophytes as well (male sporophyte only produces spores that create male gametophytes, and so on). Some plants can have just one type of sporophyte and just one type of gametophyte (in this case the single gametophyte produces both eggs and sperm)." https://lnkd.in/dDq6NXv View in LinkedIn

“TELOMERASE ACTIVATION may be possible, to help reverse natural senescence in cells. Humans lack sufficient telomerase enzyme to stop telomeres from shortening and causing aging. Telomerase activation is an area of research aimed to try and slow cellular aging.” https://lnkd.in/deXSTEu 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

ANCIENT GENE RECRUITMENT. "One prediction that can be made from the antithetic theory is that the evolution of the sporophyte involved the recruitment of ancient genes and regulatory networks from the pre-existing gametophyte generation; these networks would then diversify and promote morphological diversification in the sporophyte generation." Supported by transcriptomic studies. http://rstb.royalsocietypublishing.org/content/367/1588/508.short View in LinkedIn

ANTITHETICAL THEORY. "The sporophyte originated through the intercalation of mitotic divisions in the zygote before meiosis, resulting in a diploid embryo being retained on a gametophytic thallus; the sporophyte would then gradually evolve from a parasitic dependence on the gametophyte into a dominant, physiologically independent organism. The antithetic theory is supported by the dominance of gametophytes over sporophytes in bryophytes and by the absence of sporophytes in charophyte algae." http://rstb.royalsocietypublishing.org/content/367/1588/508.short View in LinkedIn